The Atari Compendium

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066010303050000132002006006010000 11 2- # -1 F0110000001 R [.◆....◆....◆....◆....◆....◆....◆....◆....◆....◆....◆....◆...]0010 9[....◆....◆....◆....◆....◆....◆....◆....◆....◆....◆....◆....◆....◆....◆..]1010 ü 9[....◆....◆....◆....◆....◆....◆....◆..]3010 YourSecond GFA-BASIC3.0 Manual 9[....◆....◆....◆....◆....◆....◆....◆....◆....◆....◆....◆....◆....◆....◆..]1010 SecondEdition (c)HanKempen Coevorden,1990Ç üEverythingyoualwayswantedtoknowabout GFA-Basic3.0,butwereafraidtoask 9[:::::::::::::::::::::::::::::::::::::::◆::::◆::::◆::::◆::::◆::::◆::::◆::::◆:]1010 üëCONTENTS ü êINTRODUCTIONÇ..........................7ê Ç ê1.GENERALÇê ÇStart-up..............................9 Application...........................9 Monitor...............................10 Break.................................10 OperatingSystem......................10 ê 2.THEEDITORÇê ÇAbbreviatedCommands..................12 Syntax................................12 FoldedProcedures.....................13 Tab...................................13 CutandPaste.........................13 Load..................................13 Save..................................14 Llist.................................14 Insert-mode...........................15 Directmode...........................15 DEFLIST...............................15 SpecialCharacters....................16 ê3.VARIABLESÇê ÇVariableType.........................17 DEFWRD................................17 Boolean...............................17 Integer...............................18 FloatingPoint........................18 VAR...................................18 FUNCTION..............................19 CLEAR.................................19 ERASE.................................19 DUMP..................................19 TYPE..................................20 READ..................................20 SWAP..................................20 TIME$.................................21 TIMER.................................21 DATE$.................................22 ê4.MEMORYÇ RAM...................................23 INT{}.................................23 RESERVE...............................23 INLINE................................24 MALLOC................................25 ê ê5.SORTÇê ÇQSORTv.SSORT........................26 QSORTofnumber-arrays................26 QSORTofstring-arrays................26 ê 6.OPERATORSandNUMERICALFUNCTIONSÇê Ç\.....................................29 PREDandSUCC.........................29 MOD...................................29 BCLR..................................29 BSET..................................30 BCHG..................................30 LOG...................................30 SINQandCOSQ.........................30 EQV...................................31 CARDandSWAP.........................31 MAX...................................31 Correlation...........................31 ê 7.STRINGSÇ INSTR.................................32 LSETandRSET.........................32 Parser................................32 ê 8.KEYBOARDINPUTÇ INKEY$................................33 INPUT.................................34 INPUT$................................35 LINEINPUT............................35 KEYTEST...............................35 KEYGET................................35 KEYLOOK...............................36 KEYPRESS..............................37 KEYDEF................................37 Keyboard..............................37 Keyclick,KeyrepeatandCapsLock......38 ê 9.SCREENOUTPUTÇ PRINT.................................40 LOCATE................................41 PRINTTAB.............................42 Setscreen(XBIOS5)...................42 Font..................................43 ê 10.PRINTERÇê ÇPrinterready.........................45 HARDCOPY..............................45 Printer-commands......................47 ê ê11.FILESÇ FloppyWriteTest.....................50 StepRate.............................50 RAM-disk..............................50 DIR$()................................50 DIRandFILES.........................51 FSFIRSTandFSNEXT....................52 EXIST.................................54 LOF...................................54 TOUCH.................................54 NAME..................................54 KILL..................................54 FileCopy.............................55 DiskFormat...........................55 FileAllocationTable(FAT)...........58 Sectors...............................59 Bootsector............................61 BLOAD.................................61 INPandOUT...........................62 INPUTandLINEINPUT..................62 STOREandRECALL......................62 FILESELECT............................63 ê12.MIDIÇê ÇINPMID$...............................67 INP...................................67 Midi-commands.........................67 ê 13.MODEMÇ INPAUX$...............................70 INP...................................70 Rsconf(XBIOS15)......................70 ê 14.MOUSEÇ Editor................................71 Fileselector..........................71 MOUSE.................................71 SETMOUSE..............................71 DEFMOUSE..............................72 ê 15.JOYSTICKÇ STRIGandSTICK.......................74 ê 16.SOUND ÇSOUNDandWAVE........................75 Dosound(XBIOS32)....................75 Samples...............................76 Speech................................77 Soundmachine..........................77 ê ê17.PROGRAMDECISIONSÇê ÇIF...ENDIF..........................78 SELECT................................78 ê 18.PROGRAMLOOPS ÇCalculations..........................79 FOR...NEXT..........................79 Loops.................................80ê 19.PROGRAMCONTROLÇ GOSUB.................................82 ONBREAKGOSUB........................82 ERROR.................................82 EVERYandAFTER.......................82 GOTO..................................82 DELAY.................................83 CHAIN.................................83 EXEC..................................83 ê 20.GRAPHICS ÇSETCOLORandVSETCOLOR................84 Palette...............................84 DEFMARK...............................87 DEFFILL...............................87 DEFLINE...............................89 DEFTEXT...............................89 GRAPHMODE.............................90 PLOTandDRAW.........................91 PCIRCLE...............................92 CURVE.................................92 TEXT..................................92 SPRITE................................93 VQT_EXTENT............................95 Line-A................................95 HLINE.................................96 ACHARandATEXT.......................96 GETandPUT...........................96 Degas-Pictures........................97 Neochrome-Pictures....................98 VSYNC.................................98 Scroll................................98 ACLIP.................................99 Blitter...............................99 ê21.EVENTSÇê ÇMENU()................................101 ONMENUBUTTON........................101 ONMENUIBOX..........................102 ê ê22.PULLDOWNMENU ÇOPENW0...............................103 Desk-submenu..........................103 File-submenu..........................103 ê 23.WINDOWSÇ GFA-windows...........................104 CLOSEW................................104 TITLEW................................105 CLEARW................................105 ê24.AES-LIBRARYÇ ALERT.................................106 SHEL_GETandSHEL_PUT.................106 ê25.GFAXPERT-FILESÇê ÇGFAXPERT.DOC..........................108 GFAXPERT.LIB..........................108ê ÇINLINE................................108ê ÇSTANxxxx.LST..........................108 START.................................112 ásmallprintóÇ...........................113 êEPILOGUEÇ..............................114 êINDEXÇ.................................115ê 9[....◆....◆....◆....◆....◆....◆....◆....◆....◆....◆....◆....◆....◆....◆..]1010 üëINTRODUCTION Ç ü ÇRightnowyouarereadingthesecondeditionofthetextGFAXPERT.DOC. ThistextisnotmeanttobeareplacementofyourGFA-manual.Onthe contrary,IassumeyouarealreadyfamiliarwiththeGFA-manualandnow wanttoknoweverythingaboutGFA-Basic3.0thatisnotdescribedproperly inthemanual. Thistextisaboutthe(hidden)powerofGFA-Basic3.0.Youwillfind nothingaboutversion3.5,apartfromthissentence.Andthissentence, becauseIwouldliketomentionthatIdon'tunderstandwhyGFAlaunched version3.5.GFA-Basicisbecomingfartooexpensive. Allremarksinthistext,especiallyaboutbugs,arebasedonGFA-Basic 3.07.Istillhopeversion3.08willbecomeavailable(hownaive...), otherwiseI'llhavetowaitforversion4.Notversion4.00ofcourse, becauseIknowtherewillbeatleast200bugsinthefirstrelease. IwrotethistextbecauseIwasdisappointedbythecontentsofmostbooks aboutGFA-Basic3.0.Someauthorsusepageafterpagetodescribeaboring program.Othersdelvedeeplyintomenu's,windowsandRSC,butignorethe "regular"Basic-commands.Insteadofcomplaining,Idecidedtowritethe bookthatIwouldreallyliketoseemyself.Hereitis.Forgetallother booksaboutGFA-Basic,youneedonlytwothings:yourGFA-manualandthis text.Andtobehonest,perhapsagoodbookabouttheAES-library,because youwon'tfindmuchaboutthatsubjectinthistext. InthistextyouwillfindquiteafewProcedures.MostProceduresthat arelisted(ormentioned)inthistextcanbefoundinoneoftheLST- filesinthefolderGFAXPERT.LIB.Downloadersshouldlookforthefile GFAXPRT2.ARC. Istronglyadviseyoutoreadthechapter'GFAXPERT-FILES'thoroughly, beforeyoutrytousetheProcedure-libraryGFAXPERT.LIB.Especiallynote thefollowing: (1)êwordÇ-variablesarethedefault (2)acoupleofvariablesaredeclaredasêStandardGlobalsÇ (3)someêStandardFunctionsÇaredefined (4)afewêStandardProceduresÇarepresent (5)theêStandardArrayÇcolor.index()isdeclared AProcedurecoulduseanyoftheStandardGlobals,Functions,Procedures ortheStandardArray.Iusuallymentionthisincomment-linesinthe Procedure.IfyouMergesuchaProcedureintoanexistingprogram,you willhavetoadaptyourprogramortheProcedure. IstillbelieveinGFA-Basic3.0.AndIalsobelieveinsharingideas, Proceduresandprogramswithotherusers,startingwithyou.Ifyoufeel guiltyaboutreceivingallthesegoodiesfor(almost)nothing,youwill findafreeconsultinthechapter'EPILOGUE'. ÇIcouldonlywritethistextbecausemanyGFA-userssharedtheir experiencewithothers.Idedicatethistexttothem.Specialthanksto everyonewhopointedoutbugs,mistakesandomissionsinthefirstedition ofGFAXPERT.DOC.Allmistakesinthesecondeditionaremadeby HanKempen üë1.GENERAL ü Start-upÇ ProgramsinanAUTO-folderareexecutedautomaticallyafterareset.The interpreterGFABASIC.PRGisaGEM-program,andcannotbestartedinthis way.WithTOS1.4youcaninstallaGEM-programasauto-booting.With olderTOS-versionsyoucoulduseaprogramlikeHEADSTRT.PRGinyourAUTO- foldertostartGFABASIC.PRGautomatically.Youcan'tstartaGFA-program thisway(Ithink). Ifyouhavewrittena(compiled)programthatcanberuneitherfromthe AUTO-folderorfromthedesktop,youcandeterminewhichisthecase: IFPEEK(&H2C+4)=0 !4thbyteofLine-Fvector (...) !AUTO ELSE (...) !desktop ENDIF Thereareseveralwaysto(re)startyourcomputer.Theobviousoneisto switchtheSToff,waitafewseconds(15secondswitha1040ST!),and switchonagain.Thisiscalleda"cold"or"hard"reset.Yourcomputer suffersalittle,andittakessometime.Ifyouusethereset-buttonon yourST,youperforma"warm"or"soft"reset.Theoperatingsystem automaticallyperformsawarmresetifyouswitchbetweenLowandMedium resolutiononthedesktop.Ifyoususpectaprogramofchangingsystem variables,youshouldalwaysuseacoldreset.Afterawarmresetthe systemvariablesinlowmemoryareênotÇinitialisedagain.Garbagewill staythereandwillundoubtedlyleadtointerestingeffects.Youcan performbothawarmandacoldresetfromGFA-Basicwiththefollowing Procedures: PROCEDURE coldstart SLPOKE &H420,0 SLPOKE&H426,0 !probablynotnecessary SLPOKE &H43A,0 ~XBIOS(38,L:LPEEK(4)) RETURN ' PROCEDURE warmstart ~XBIOS(38,L:LPEEK(4)) RETURN Ifyouwouldliketobootfromyoursecond(external)driveB,try: SLPOKE&H446,1 !bootfromdriveBafternextreset @warmstart üApplicationÇ ItisconvenienttoinstalltheextensionGFAasanapplicationfor GFABASIC.PRG.ClickonceonGFABASIC.PRGandchooseInstallApplication fromtheOptions-menu.TypeGFAasDocumentType,clickonOKandsavethe desktop.Ifyoudouble-clickaGFA-program(extension.GFA)fromthe Çdesktop,GFABASIC.PRGisautomaticallyloadedfirst.ChoosingInstall Applicationyouwillonlyseethemostrecentlyinstalledapplication.Use adisk-editortoexaminethefileDESKTOP.INFandyouwillfindall installedapplications(lookfor#G).Youcouldalsousethemethod describedintheparagraph'SHEL_GETandSHEL_PUT',ortheRECALL-method fromtheparagraph'STOREandRECALL'. üMonitorÇ TheAtaricolourmonitorSC1224workswithaverticalfrequencyofeither 50Hzor60Hz: SPOKE&HFF820A,254 !50Hz SPOKE&HFF820A,252 !60Hz For60Hz,bit1oftheSyncModeRegisteriscleared.Don'tchangebit0, orthevideocontrollerchipwillnotusetheso-calledsyncpulses.After areset,theoperatingsystemdefaultsto50Hz.Thescreenisalittle largerthanat60Hz,butthescreenflickersslightly.Ifyouconnect yourSTtoaTVthroughamodulator,youshoulduse50Hz.Otherwiseyou areadvisedtouse60Hz. üBreakÇ It'snoteasytofindintheGFA-manual:youcanstoparunningprogramby pressing<Control><LeftShift><Alternate>simultaneously.Butifyou're readingthistext,youknowthisalready.It'simpossibletointerrupta programduringDELAY!StudytheStandardProcedureBreakinoneofthe STANxxxx.LST-filestoseehowIreactaftera'Break'. üOperatingSystemÇ IfyouprograminalanguagelikeGFA-Basic,youwon'tnoticemuchofthe actualworkhorseinsideyourST-computer:TheOperatingSystem(TOS).But evenGFA-BasicdoesnothaveaBasicequivalentforallTOS-functions, althoughyoucanusealmostallfunctionsfromGFA-Basic. TOScanbedividedintwomainparts:(GEM)DOSandGEM.Thefirstisa collectionof"lowerlevel"routinesforcommunicationwithkeyboard, screen,printer,etc.InGFA-Basicyoucancalltheseroutineswiththe commandsBIOS,XBIOSandGEMDOS.TheGraphicsEnvironmentManager(GEM) consistsoftwocollectionsofroutines:theVDI(VirtualDevice Interface)andtheAES(ApplicationEnvironmentServices).TheVDItakes careofregulargraphicsandshouldhaveincludedGDOS.Atarididn't includeGDOSintheVDI,soyouhavetoloaditifyouneedit.MostVDI- functionshaveaBasicequivalentinGFA.TheAEStakescareofthe communicationwiththeuserthroughmenu,Alert-box,window,etc.Most AES-functionscanbeaccessedthroughtheAES-libraryinGFA-Basic3.0. WithGEMDOS-function48(Sversion)youcanfindtheversionofyour GEMDOS.ForboththeoldTOSandtheBlitter-TOS&H1300(version0.19)is returned.TheFrenchTurbo-DOShasversion0.20andthenewRainbowTOSof 1988hasversion0.21. ÇAnotherwaytofindouttheversionofTOSusesthesystemheaderofTOS (notnecessarilylocatedinROM!): adr%=LPEEK(&H4F2) version$=HEX$(DPEEK(adr%+2)) ThegoodoldROM-TOS(1986,actuallynotsogood)hasversion&H0100 (1.0),theMega-STBlitter-TOS(1987)version&H0102(1.2).Andofcourse thenewTOS('RainbowTOS')hasversion1.4.Youcouldalsoexaminethe dateofyourTOS-version: date$=HEX$(LPEEK(adr%+24)) MyancientTOS1.0has'11201985'asthedate. üë2.THEEDITOR ü AbbreviatedCommands Ç Theeditorrecognizesthefollowingabbreviations(notacompletelist): ALINE -ALI FILESELECT-FILE POLYMARK -POLYM ARECT -AR FILL -FI PRINT -Por? ARRAYFILL -ARR FUNCTION -FU PROCEDURE-PRO ATEXT -AT GOSUB -Gor@ PSET -PS BMOVE -B GRAPHMODE -GRA QUIT -Q BOUNDARY -BOU HIDEM -HI REPEAT -REP CASE -CA HLINE -HL RESTORE -RES CIRCLE -CI IF -I RETURN -RET CLOSE -CL INPUT -INP RSET -RS COLOR -C LINE -LI SELECT -S DATA -D LINEINPUT-LI SETCOLOR -SET DEFFILL -DEFF LOCAL -LOC SETMOUSE -SETM DEFLINE -DE LOOP -L SGET -SG DEFMARK -DEFMA LPRINT -LPR SHOWM -SH DEFMOUSE -DEFM LSET -LS SWAP -SW DEFTEXT -DEFT MID$(..)= -MI ..)= TEXT -T DELETE -DEL MOUSE -MOU UNTIL - U DRAW -DR NEXT -N VOID -V EDIT -ED OPEN -O VSYNC -VS ELLIPSE -ELL PAUSE -PA WAVE -WA ELSE -E PBOX -PB WEND -WE ENDFUNC -ENDF PCIRCLE -PC WHILE -W ENDIF -EN PELLIPSE -PE ENDSELECT -ENDS PLOT -PL ERASE -ERA POLYFILL -POLYF EXITIF -EX POLYLINE -POL Iftheabbreviatedcommandisfollowedbyanythingelse,youhaveto insertaspace(e.g.'C1'),exceptwith'@'and'?': @proc1 Gproc1 ' ?"hello" P"hello" üSyntax Ç Theparserchecksforcorrectsyntaxafteryoupress<Return>.Manytypo- bugsarepreventedthisway.Theonlydisadvantageisthattheparser recognizessomevariablesascommands.It'simpossibletousethefollo⑨ wingnamesastheêfirstÇwordonaline:data_byte|,dirty$,double, printer$,file%,quit!.Thelastoneisnasty,becausetheparserchanges theline'quit!=FALSE'into'QUIT!=FALSE'withoutwarningforasyntax- error.IfyounowruntheprogramyouwillreturntothedesktopwhenQUIT isencountered.Ofcourseyouhavenotlostyourvaluableprogram,because youalwaysSavebeforeyouRun.Doyoureally?Iftheparserrefusesthe Çnameofavariable,youcanuseLET(e.g.'LETquit!=FALSE').Butyouwill havetochangethenameifitisalabel(e.g.thelabel'data1:'couldbe changedinto'1data:'or'd.ata1:'). üFoldedProcedures ÇIfyoupress<Control><Help>onaProcedure-line,allProceduresfollo⑨ wingandincludingthecurrentonearefolded/unfolded.Youcanunfoldall ProceduresatoncebyputtingthecursoronthefirstProcedure-lineand pressing<Control><Help>.IsuggestyouleaveallProceduresinthe Procedure-LibraryGFAXPERT.LIBfolded,unlessyouwanttoexaminea Procedure.Theeditor-commands'Find'and'Replace'willskipfolded Procedures.NeverchangetheProcedure-lineofafoldedProcedure,always unfolditfirst. üTab Ç Ifyoupress<Tab>,thecursorjumpstothenexttab-position,without alteringthecurrentline.Ifyouuse<LeftShift><Tab>,thelineis filledwithspacesfromthecurrentcursor-positiontothenexttab- position.Pressing<RightShift><Tab>erasesallconsecutivespacesto theleftofthecurrentcursor-postition.Ifthecurrentcursor-position happenstobeaspace,thisspaceandallspacestotherightareerased aswell. üCutandPasteÇ Ifyoupress<Control><P>,thecurrentlinefromthecursortotheendof thelineiscut,andsavedinaninternalbuffer.<Control><O>inserts thesavedlineatthecurrentcursor-position.Youcanusethismethodto "cutandpaste"apartofaline.Press<Control><P>,then<Control><O> torestoretheoriginalline.Movethecursortothedesiredpositionand press<Control><O>.Block-operationsareonlypossiblewithcomplete lines. üLoad Ç YoucanuseLoadonlywith*.GFA-files,notwithASCII-files(suchasthe *.LST-files).ST-BasicfilesareASCII-files,soyoucanMergethem. MorerecentprogramsinGFA-Basic(from3.04)cannotbeloadedbyearlier interpreters(upto3.02).Ofcourseyoushouldhavethemostcurrent version(atleastversion3.07),butthefollowingmethodshouldalways work.Lengthentheprogramuntilyoucanloaditsuccessfully: OPEN"A",#1,file$ PRINT#1,STRING$(1000,0) CLOSE#1 üSaveÇ After'Save'(*.GFA-file)or'Save,A'(*.LST-file)withanexistingfile, theoldfileisrenamedwithaBAK-extension.Niceprecaution,butyou shoulddeletethose*.BAK-fileseverynowandthen. Ifyoukillandsavefilesregularly,newfileswillbestoredina fragmentedway.Loadingafragmentedfiletakesmoretimethanloadinga filethatoccupiesconsecutivesectorsonthedisk.Youcancorrectthis asfollows.Firstmakeabackup-disk(yes,youshouldalreadyhaveone). CopyallfilestoaRAM-diskbyclickingonthedrive-iconanddraggingit tothewindowofthedestinationdrive.Youcan'tusedisk-copy(dragging drive-icontodrive-icon)becausethedestination-driveisaRAM-disk. Formatthesource-diskandcopyallfilesback(thisêmustÇbeafile-copy, notadisk-copy).Now,allfilesaresavedonconsecutivesectors.You couldspeedupthingsalittlebitmorebycopyingthemost-usedfiles first.Thedrive-headnowneedslesstimetoreachthesefiles. Don'ttryto'Save,A'anexistingfiletoafulldisk.Ihavetriedit onceandlostboththeoriginalfile(shouldhavebecomea*.BAK-file)and ofcoursethesavedfile.Also,theeditor(orTOS)haderasedtheprogram frommemory...Thankyou. üLlistÇ Therehasbeensomeconfusionaboutthefollowingpoint-commandsforthe printer: .p- -point-commandsarenotprinted .p+ -point-commandsareprintedagain .llxx -line-width .plxx -page-length .pa -formfeed Sometimesthecommands'.cp'and'.nu'arementioned,butIdon'tknowhow tousethese. Youcanonlyuseonepoint-commandinoneline.Iusethefollowinglines formyprinter(96characters/lineinElite-mode): .p- .n4 .lr3 .ll88 SavethisasLLIST.LSTandMergeitafterthelastlineofaprogram beforechoosing'Llist'.Theactuallistingisthenprintedwith80 characters/line,precededbytheline-numbers(4characters+space).If yourprogramislongerthan10000lines,youshoulduse'.n5',butinthat caseyouprobablydon'thavetimetoreadthis.Anicetouchisthe automaticexecutionofaformfeedafterprintingthelisting. Ifthelistingcontainsspecialcharacters(ASCII-code<32or>126), someofthosecharactersmightbeinterpretedasprinter-commands.My printerswitchestocondensedprintingafterreceivingtheAtari-symbol. Installingtheproperprinter-driver(e.g.PTEPSON.PRG)willpreventthat. ÇButIneverinstallaprinter-driverbecausetherearesomeserious disadvantages.Readmoreaboutitintheparagraph'HARDCOPY'. Youcanstoptheprintingprocessbypressingthe'Break'-combination <Control><LeftShift><Alternate>,unlessBreakhasbeendisabledwith 'ONBREAKCONT'.Yourprinterwillcontinueprintingthough,untilits input-bufferisempty,oruntilyouturntheprinteroff. ü Insert-mode Ç Ifyoureturntotheeditor,you'llalwaysbeinInsert-mode,evenifyou lefttheeditorinOverwrite-mode.Bytheway,theeditorrestoresthe originalcolour-palette,soyouarenotbotheredbypalette-changesina program.IntheolddaysIwassometimescaughtbythedreadedphenomenon ofblackcharactersonablackbackground,butnowyoucanalwaysreadthe listingonyourscreen. Bythesecondway,thereisonlyonethingIdon'tlikeabouttheGFA- editor.It'snoteasytomergeaProcedurefromaLST-filewiththe programyou'reworkingon.Savetheprogram,clearmemorywith'New', 'Merge'theLST-file,marktheProcedureasablock,savetheblock, 'Load'theoriginalprogram,findthecorrectlineand'Merge'thesaved block.AnewcommandNMerge(New+Merge)wouldmakethelifeofaGFA- programmeralittleeasier.AbetterideawouldbethecommandBMerge (Block-Merge).ThenIcouldchoosethiscommand,clipaProcedure-block, andtheblockwouldbeinsertedinthelistingautomatically.Areyou readingthis,Frank?Ifyouare,howaboutafunctionforchangingupper caseintolowercase.IntheGFA-EDITORISOMETIMES(oops)forgetI pressedCapsLock.Andhowaboutafunctiontoclearalinefromthecursor tothenextspace-character.And... üDirectModeÇ EntertheDirectModebypressing<Esc>or<Shift><F9>intheeditor. InDirectModeyoucanrestorethepreviouslyusedlinewith<Undo>.With <Uparrow>and<Downarrow>youcanevenrecallupto8ofthelastused lines.Press<Insert>toswitchbetweenInsert-modeandOverwrite-mode.As usual<Esc>clearstheline,butifyoupress<Esc>onanemptyline,you willreturntotheeditorimmediately.Youcanalsoreturntotheeditor with<Control><Shift><Alternate>,evenwithoutfirstclearingthe command-line.YoucancallProceduresinyourprogramfromtheDirectMode (e.g.'@show').Ifyou(temporarily)mergesomespecialProcedureswith theprogramyouaredeveloping,youcouldusetheDirectModeasaCommand LineInterpreter. üDEFLISTÇ Thecommand'DEFLISTn'onlyworksinDirectMode,notinaprogram.You canalsochoose'Deflist'fromthedrop-downmenu,afterclickingonthe Atari-symbol. üSpecialCharacters ÇYoucanentercharacterswithASCII-codeüÇ32-126üÇdirectlyfromthekey⑨ board.ThesecharactersareusuallycalledASCII-characters.Thecodes 0-31and127areusedascontrol-codes,butadditionallyspecialcharac⑨ tershavebeenassignedtothesecodes.Thecharacterswithcode128-255 aresometimescalled"extendedASCII-characters"andarepartlyidentical totheIBM-characterswiththesamecodes.Ilooselyusetheexpression "ASCII-code"forallcodes0-255.  Youcanentercharacterswithcode0-31or127-255bypressing<Alternate> andthenenteringthecharactercode.Releasethe<Alternate>-keyandthe characterappearsonyourscreen.E.g.,youcouldentertheEscape- characterbyholding<Alternate>downandpressing<2>and<7>.Thisis muchfasterthanenteringCHR$(27),butLlistingafilewithEscape- charactersisprobablynotagoodidea(lessimportant,1stWordPlus couldgetconfusedtoo).LlistingCHR$(27)doesn'tbotheryourprinterat all.It'snotpossibletoenterCHR$(10)orCHR$(13)withthe'Alternate'- way.Youcanenterthefirstbypressing<Control><A>andthen<1><0> <Return>.Forcode13youhavetouseCHR$(13). Neverusecode4(EOT,visibleasleftarrow)inaLST-file.IfyouMerge aLST-file,theGFA-editorthinkstheendofthefileisreachedatthat point(&H04)andrefusestoloadanythingfollowingthiscode! üë3.VARIABLES Ç üVariable-typeÇ InGFA-Basicweusetheexpressions'Byte','Word'and'Integer'forthe threeinteger-variables.Becauseallthreeareintegers,theexpression 'Integer'forthe4-byteinteger-variableissligthlyconfusing.Inother languagesthisvariableiscalled'Longword'orsimply'Long'.Anaddress inRAMshouldalwaysbea4-byteinteger. ü DEFWRDÇ Iprefertodeclareword-variablesasthedefault(forvariableswithout postfix)with:DEFWRD"a-z" Irecommendtheuseofword-variables(2bytes)fortworeasons.In calculations,theuseofthespecialinteger-operators(ADD,SUB,INC, etc.)speedstheprogramupconsiderably.Ifyouinsistonusingthe regularoperators(+,-,etc.)youshouldusefloatingpointvariables instead.Usingtheregularoperators,theinterpreterhastoconvert integer-variablestofloatingpoint,doesthecalculationandconvertsthe resultbacktointegeragain.That'swhya#*b#iscalculatedfasterthan a&*b&.ButMUL(a&,b&)ismuchfasterthana#*b#.Ittakessometimeto recognizewhatanexpressionlikeDIV(a,MUL(ADD(a,b),SUB(b,c)))means.I suggestyouusetheregularoperatorsifthecalculation-timeisnot critical.Inloops,thegainincalculationtimereallycounts,soyou shouldusetheinteger-operators.ThatwayyouwilllearnPolishtoo.The secondreasonforusingword-variablesis,thatinacompiledprogram calculationswithword-integersareusuallythefastest. IMPORTANT:ifanumber-variablehasnopostfixinthistext,youshould assumeit'saêwordÇ-variable.I'llusethepostfix|,%or#where appropriate.Pleasenotethattheinterpreterassumesanumber-variable withoutpostfixisafloatingpointvariable,unlessyouuseDEFWRD"a-z". üBooleanÇ Thefollowingfivelines: IFnumber>0 test!=TRUE ELSE test!=FALSE ENDIF canbeshortenedtojustoneline: test!=(number>0) Thisworks,becausethe'>'-operatorreturnsTRUEorFALSE(actually-1 or0). ÇAnotherlittletrick: IFi=1 n=n*2 ELSEIFi=2 n=n*5 ELSE n=0 ENDIF Thiscouldbeshortenedto: n=n*-2*(i=1)üÇ+n*-5*(i=2) Theexampleisridiculous,buttheprincipleinvolvedcouldbeuseful.The expressions'i=1'and'i=2'areeither0(FALSE)or-1(TRUE). Itisnotnecessarytousesomethinglike: IFflag!=TRUE (...) ENDIF Youcansimplyuse: IFflag! (...) ENDIF üIntegerÇ Youcan'tassign2^31toa4-byteinteger-variable.Althoughaninteger contains32bits,youcan'tusebit31.Thisbitisaflagforanegative integer.Thelargestpositivenumberyoucanassigntoaninteger-variable istherefore2^31-1(2147483647).Icouldhavewrittenananalogue paragraphaboutthe2-byteword-variables,butIdidn't. ü FloatingPoint Ç Therangeoffloatingpointvariables(postfix#)is: -1.0E1000<x#<1.0E1000 LargerorsmallernumbersêcanÇbeusedincalculations,butnotprinted, becausetheexponentmaycontainnotmorethan3digits(1.0E1000is displayedas1.0E;00). üVAR Ç IfyoucallaProcedureanduseVAR(callbyreference),êallÇvariables and/orarraysafterVARarecalledbyreference.Anexampletoclarify this: @test(10,5,number%,array%()) (...) PROCEDUREtest(a,b,VARx%,y%()) 'nowa=10andb=5(callbyvalue) 'number%andarray%()cannowbeusedasx%andy%() x%=a+b !globalvariablenumber%isnow15 ARRAYFILLy%(),1 !allelementsofarray%()arenow1 RETURN ÇInprehistoricdaysyoucouldhaveusedSWAP,butVARmakeslifeeasier: @test(*a%()) (...) PROCEDUREtest(ptr%) SWAP*ptr%,x%() !arraya%()temporarilyrenamedasx%() (...) !dosomethingwiththearray SWAP*ptr%,x%() !restorepointerbeforeleavingProcedure RETURN üFUNCTIONÇ YoucanonlyleaveaFUNCTIONbyRETURNingavalueorastring.This value/stringisusuallyassignedtoavariable.IftheFUNCTIONreturnsa string,thefunction-namehastoendwith'$': FUNCTIONtest RETURN126 ENDFUNC ' FUNCTIONtest$ RETURN"thisisastring" ENDFUNC ü CLEARÇ BecauseCLEARisautomaticallyexecutedwhenyourunaprogram,it'snot necessarytostartyouprogramwiththiscommand. ü ERASEÇ It'simpossibletoreDIMensionanexistingarray.YoufirsthavetoERASE theexistingarrayandthenyoucanDIMensionanewarray.Itisnot necessarytotestfortheexistenceofanarraywithDIM?()beforeyouuse ERASE.Inotherwords,youcanuseERASEevenifthearraydoesn'texist: ERASEarray$() !justincasethisarrayalreadyexists DIMarray$(200) AfterERASEinganarray,GFArearrangestheremainingarrays.Allarrays thathavebeenDIMensionedafterthedeletedarrayaremovedinorderto fillthegapofthedeletedarray.ThisisimportantifyouuseV:array(0) inyourprogram(readtheparagraph'RESERVE'). üDUMPÇ Examineallvariablesinyourprogrambytyping'DUMP'inDirectMode. Press<CapsLock>toslowdownthescrolling-speed,orpresstheright <Shift>-keytotemporarilystopthescrolling.TheProcedureDebugenables youtouseDUMPduringdebugging.Thisisthebestwaytodiscoverthose nastytypo-bugsinavariable-name.You'llprobablybesurprisedtosee thenamesofdeletedvariablesaswell.Also,anyvariable-nameyouused inDirectModeappears.êAllÇthesenamesareSAVEdwiththeprogram!Delete Çallunwantednamesasfollows(aRAM-diskwouldbeconvenient): -Loadthefile -Save,A(press<Return>inFileselector) -New -Merge(press<Return>again) -Save(press<Return>oncemore) Thefilecouldbemuchshorterafterthisoperation. üTYPE ÇThecommandTYPEdoesnotseemtoworkproperlyifyouuselocal variables.Idon'tknowwhat'swrong. üREADÇ Asarule,IalwaysRESTOREtheappropriatelabelbeforeREADingDATA- lines.ThatwayIcanuseDATA-linesinProcedures: PROCEDUREread.data  RESTOREthese.data (...) !READtheDATAhere these.data: DATA1,2,3,4 RETURN üSWAPÇ The52cardsinbridge(oranothercard-game)canberepresentedbya byte-array.Filltheelements1-52ofthearraywiththevalue1-52.The values1-13wouldrepresenttheClub-cards(2,3,4,...,Q,K,A),values 14-26theDiamonds,values27-39theHeartsandvalues40-52theSpades. ShufflingthecardscannowbesimulatedwiththeProcedureShuffle: DIMdeck|(52) FORi=1TO52 !ignoreindex0 deck|(i)=i NEXTi @shuffle(deck|()) (...) PROCEDUREshuffle(VARproc|()) LOCALi,j FORi=DIM?(proc|())-1DOWNTO2 j=RAND(i)+1 SWAPproc|(j),proc|(i) NEXTi RETURN üTIME$Ç YoucanuseTIME$toprintthecurrenttimeonthescreen.Inthe ProcedureTimeyou'llfindawaytoprintthetimeeverysecond,although TIME$isupdatedeveryêtwoÇseconds: PROCEDURE time ' *** activate with : EVERY 200 GOSUB time ' *** global : TIMER$ LOCAL t$ t$=TIME$ IF t$=timer$ MID$(timer$,8)=SUCC(RIGHT$(timer$)) ELSE timer$=t$ ENDIF PRINT AT(1,1);timer$ RETURN üTIMERÇ Ifyouneedastopwatch,youcanusethefollowingProcedures: PROCEDURE stopwatch ' *** global : STOP.SECONDS# STOP.H STOP.M STOP.S WATCH.ON! LOCAL s# IF watch.on! stop.watch#=TIMER stop.seconds#=(stop.watch#-start.watch#)/200 stop.h=stop.seconds#/3600 s#=stop.seconds#-stop.h*3600 stop.m=s#/60 stop.s=s#-stop.m*60 watch.on!=FALSE ELSE watch.on!=TRUE start.watch#=TIMER ENDIF RETURN ' PROCEDURE print.stopwatch IF stop.h>0 PRINT stop.h;" h ";stop.m;" m"; ELSE IF stop.m>0 PRINT stop.m;" m ";stop.s;" s"; ELSE IF stop.seconds#>=10 PRINT USING "##.# s",stop.seconds#; ELSE PRINT USING "#.## s",stop.seconds#; ENDIF ENDIF ENDIF RETURN ÇYoustartthestopwatchbycallingtheProcedureStopwatch.Callingthis Procedureagainwillstopthestopwatch.ThenyoucanPRINTtheelapsed timeatthecurrentcursor-positionwiththeProcedurePrint.stopwatch,or youcoulduseoneoftheGlobalVariablesfromtheProcedureStopwatchto dosomethingelse. üDATE$ Ç FindthedayoftheweekwiththeProcedureDay.of.week: PROCEDURE day.of.week(day.date$,VAR day$) LOCAL day,mp,month,year,m,h,w,week$,n day=VAL(LEFT$(day.date$,2)) mp=INSTR(day.date$,".") month=VAL(MID$(day.date$,mp+1,2)) year=VAL(RIGHT$(day.date$,4)) IF month<=2 m=10+month year=year-1 ELSE m=month-2 ENDIF h=year/100 y=year-100*h w=(TRUNC(2.6*m-0.2)+day+y+TRUNC(y/4)+TRUNC(h/4)-2*h) MOD 7 RESTORE weekdays FOR n=0 TO w READ day$ NEXT n ' weekdays: DATA Sunday,Monday,Tuesday,Wednesday,Thursday,Friday,Saturday RETURN ThisProcedureusesZeller'sCongruencetodeterminethedayoftheweek. üë4.MEMORY Ç üRAMÇ Anoverviewofthememoryofmy1040ST(startatthebottom): êaddressÇ &HFFFFFtopofmemoryof1040ST(1024K) &HFFD00 767unused(?)bytes XBIOS(2)=&HF8000screenmemory(32000bytes) HIMEM=&HF400016384unusedbytes(MALLOC(-1)) &H.....freememory(lengthFRE(0)bytes) &H388EAprogram+variables(lengthvaries) &H10C2EGFA-Basic3.07interpreter  BASEPAGE=&H10B2EBasepageGFA-Basic(256bytes) &HA100startofavailableRAM &H6100globalAES-variables &H29B4globalBIOS-andGEMDOS-variables L~A=&H293ALineAvariables &H93AlocalBIOS-variables+BIOS-stack &H400BIOSsystem-variables &H0exceptionvectors TheBIOSsystem-variables(&H400-&H4FF)are"castinconcrete"byAtari. Other(undocumented)variablesinRAMshouldbeavoided. üINT{}Ç YoucanuseeitherINT{adr%}orWORD{adr%}.Asyouknow,w=WORD{adr%}is fasterthanw=DPEEK(adr%),butyoucan'tuseWORD{}andtheotherrelated commandsinsupervisormode.Thismeansyoucan'taccessmemorybelow address&H800.OfcourseyoucanPEEK/DPEEK/LPEEKeverywhere(DPEEKand LPEEKonevenaddressesonly),andyoucanuseSPOKE/SDPOKE/SLPOKEto writeinsupervisormode. üRESERVEÇ ThecommandRESERVEcanbeusedinthreedifferentways: RESERVEn%:reserven%bytesforGFA-Basic,releaseRAMuptoHIMEM RESERVE-n%:reservelastn%bytesofRAMuptoHIMEM RESERVE:restoretooriginal Thesecondcommandismyfavourite.YouêmustÇuseamultipleof256with RESERVE.After'RESERVE-400',only256bytesarereleasedtoGEMDOS.In thiscaseyouwouldhavetouse'RESERVE-512',althoughyouneedonly400 bytes!UsetheFunctionMultipleifarithmeticisnotyourstrongest point : RESERVE-@multiple(n%,256) Use'RESERVE-n%'onlyonceinyourprogram.IfyouRESERVEmemorya secondtimewith'RESERVE-m%',GFAreleasesm%bytes,ênotÇn%+m%. ÇThecommandRESERVE(restore)doesnotalwaysfunctionproperly.Especial⑨ lyafterEXEC3it'softenimpossibletorestorethememory.Isuspect thishassomethingtodowiththeuseofthemalloc-functionbythe operatingsystem.Youcouldtrythefollowing: RESERVE-n% !reserveasmuchasneeded(multipleof256) base%=EXEC(3,...) !load,butdon'tstart (...) ~MFREE(HIMEM) !memoryaboveGFA-Basic ~MFREE(base%) !memoryfromBasepageofloadedprogram RESERVE !hopeitworksnow Don'tbesurprisedbyhang-upsorbombsafterthisoperation... Thereareseveralwaystoreserveapartofmemoryforspecialpurposes suchasmusic,picturesorotherprograms.E.g.,youcoulduseastring- variabletostoreacompletescreenoraGET-picture.Don'tusestringsif garbagecollectionisaseriousrisk.Ifalargearrayisdeclared,the interpretersometimesmovesthestringsinmemorytocreatespaceforthe newarray.Ifyouassignanewstringtoanexistingstring-variable,the oldstringisnoterased.Duringgarbagecollectionallunusedstringsare deletedandtheactivestringsarerearranged.Thismeanstheaddressofa string(accessedthroughVARPTRorV:)isnotfixed.That'snotimportant foraGET-picture,because'PUTx,y,pic$'stillworksallright.Butif youswapscreenswith~XBIOS(5,L:adr%,-1,-1),orcallaroutinewith ~C:adr%(...),garbagecollectionwillbefatal.Onesolutionisnottouse avariablefortheaddress,buttouseVARPTRorV:.Adifferentapproach wouldbetheuseofabyte-array: OPEN"I",#1,file$ LETbytes%=LOF(#1) !howmuchspaceisneeded? CLOSE#1 DIMassembler|(bytes%-1)!createspaceforassembler-routine adr%=V:assembler|(0) BLOADfile$,adr% !loadtheroutine Youcanusethevariableadr%safely,becauseagarbagecollectionhasno influenceonarrays.However,afterERASEinganarray,allarraysthat havebeenDIMensionedafterthedeletedarrayaremovedinmemory.Sothe array-methodisnotreliableeither,unlessyouarecertainthatERASE willnotbeusedafteryouhavedeterminedtheaddressofthebyte-array. Anothersolutionwouldbetodeclarethebyte-arrayearlyinyourprogram, soitwillnotbemovedafterERASE.Theonlycompletesafewayistheuse ofINLINEorMALLOC. üINLINEÇ UseD(=DUMP)todumpanInline-fileinHex-codetotheprinter. Don'tuse'Save,A',becauseyouwilllosetheInline-code.Youcan'tuse INLINEinLST-files.IfyouwouldliketouseINLINEincombinationwitha LST-fileyoucouldproceedasfollows.First,createanINLINE-folderin themaindirectoryandSAVEtheInline-codeasafile(extensionINL)in thisfolder.MergetheLST-fileinyourprogramandloadtheInline-code intheINLINE-line.Theprogramshouldbesavedwith'Save'. ÇTheonlylimitationwithINLINEisthemaximumlengthof32746bytes.If youneedmorespace,youhavetouseMALLOC. IfyouchangethelengthofanexistingINLINE-line,theeditorsometimes erasesafewlinesfromyourprogram.It'ssafertocompletelydeletethe oldINLINE-lineandthenenterthenewINLINE-line. üMALLOCÇ ThisishowyoucoulduseMALLOC: unused%=MALLOC(-1) !"unused"memoryaboveHIMEM(usedbyGEM) RESERVE-n% !releaselastn%bytestoGEMDOS max%=MALLOC(-1) IFmax%<>0 adr%=MALLOC(max%-unused%) !n%bytesnowavailabletoGFA-Basic ELSE 'error ENDIF (...) !dosomethinginteresting ~MFREE(adr%) !givebacktoGEMDOS... RESERVE !andbacktoGFA-Basic Atarirecommendsyouleaveatleast8KtoGEM,soyoucan'tgowrongif youleave16384bytestoGEM(seeparagraph'RAM'). DoênotÇuseMALLOCtoallocatealotofsmallmemory-blocks,asGEMDOSwill getconfused.Thisproblemisrelatedtothe"40-folderlimit",because MALLOCusesthesamebufferthatisusedtostoreinformationabouta folder(seeparagraph'FILESELECT').Allocateonelargeareaandsplitit upinasmanypartsasyouneed.AlsoconsidertheuseofINLINE,strings orbyte-arraysinsteadofusingMALLOC(readtheparagraph'RESERVE').Do notuseMALLOCinanaccessory,ortheallocatedmemorymaybelostifthe userchangestheresolution. MALLOC(-1)returnsthesizeoftheêlargestÇavailablememory-block.Expect problemsifanotherprogramhasallocatedacoupleofseparatememory- blockstoGEMDOS.InthatcaseyouwouldhavetouseMALLOC(-1)again, untilareturnedvalueof'0'indicatestherearenomorememory-blocks available. üë5.SORT Ç üQSORTÇüv.SSORTÇ QSORTisfasterthanSSORT,unlessthearrayisalmostsortedalready.I understandQSORTusestherecursiveQuick-sortmethod,soyouneedmore memorythanwithSSORT(iterativeShell-sort).Sort-freakscanstudythe ProceduresQuick.sort.intandShell.sort.inttoseehowtheQuick-sortand Shell-sortcanbeimplementedwithordinaryGFA-Basiccommands(likethat dance:Quick,Shell,slow). üQSORTofnumber-arrays ÇNumber-arrayscanbeQSORTedinthreedifferentways: QSORTx%() -sortsarray;alsowithx|(),x&()orx#() QSORTx%(),n -sortselements0throughn-1 QSORTx%(),n,y%() -elementsofy%()areswappedtoo Inallcasesx%(-1)resultsinsortingindecreasingorder. Thethirdmethodisinterestingifyouneedasortedoutput,butdon't wanttochangetheoriginalarray.Youcanaccomplishthisasfollows: -copyx%()totemporaryarraytemp%() -determineindexoflastelement:last=DIM?(temp%())-1 -createindexarray:DIMindex%(last) -fillindex-arraywithindex0throughlast -sortarray:QSORTtemp%(),last+1,index%() -ERASEtemp%() Theindex-arrayêmustÇbeaninteger-array(postfix%).Also,thenumberof elementsisênotÇoptionalifyousortwithanindex-array.Youcannow printthenumbersinarrayx%()inincreasingorder: FORi=0TOlast PRINTx%(index%(i)) NEXTi IhaveneverseenthecorrectsyntaxforQSORTinprint,sohereitis: QSORTx([s])[,n[,y%()]] üQSORTofstring-arraysÇ Astring-arraycanbesortedinthesamethreewaysasdescribedfor number-arrays.Ifyouhavecreatedanindex-arraywithlast_name$(),you couldprintanalphabeticallist: FORi=0TOlast PRINTfirst_name$(index%(i))'last_name$(index%(i)) NEXTi Therearetwoextrapossibilitieswithstring-arrays. ÇForthefirstpossibility,createabyte-arrayandfillwithappropriate ASCII-values: DIMascii|(255) ARRAYFILLascii|(),32!CHR$(32)isthespace-character FORi=48TO57 ascii|(i)=i !0-9 NEXTi FORi=65TO90 ascii|(i)=i !A-Z NEXTi FORi=97TO122 ascii|(i)=SUB(i,32) !a-zconvertedtoA-Z NEXTi Allcharactersthatarenotnumbersorletterswillbetreatedasaspace (ASCII-value32).Usethearrayascii|()forsortingastring-array: QSORTx$()WITHascii|() Now'Atari'and'ATARI'aretreatedexactlythesame,becausethe interpreterusesthearrayascii|()toconvertlowercaseletterstempora⑨ rilytouppercaseêbeforeÇsorting.Youcaneventreattheinternational characters(ASCII-values>127)correctly,e.g.ascii|(129)=85.Useafew DATA-linestoaddthecorrectASCII-value,likethis: DATA128,67,129,85,130,69 Youcancombinethismethodwithanindex-arrayaswell.Thecorrect syntaxis: QSORTx$([s])WITHb|()[,n[y%()]] Ifyouhavedoneyourhomework,youshouldnowbeabletowriteaclever alphabeticalsorting-programyourself.Youwantedtobecomeanexpert, didn'tyou?CompareyourprogramwiththeProceduresAscii.qsortand String.index.qsort: PROCEDURE ascii.qsort(VAR txt$()) IF DIM?(ascii|())=0 @initio.ascii.array ENDIF QSORT txt$() WITH ascii|() RETURN ' PROCEDURE initio.ascii.array LOCAL i,code1,code2 DIM ascii|(255) ARRAYFILL ascii(),32 ! fill with space-character FOR i=48 TO 57 ascii|(i)=i ! 0 - 9 NEXT i FOR i=65 TO 90 ascii|(i)=i ! A - Z NEXT i FOR i=97 TO 122 ascii|(i)=SUB(i,32) ! a - z, converted to A - Z NEXT i RESTORE ascii.data REPEAT READ code1,code2 ascii|(code1)=code2 UNTIL code1=0 Ç ' ascii.data: ' *** format : ASCII-code,replacement DATA 128,67,129,85,130,69,131,65,132,65,133,65,134,65,135,67 DATA 136,69,137,69,138,69,139,73,140,73,141,73,142,65,143,65 DATA 144,69,145,65,146,65,147,79,148,79,149,79,150,85,151,85 DATA 152,121,153,79,154,85,155,67,158,83,160,65,161,73,162,79 DATA 163,85,164,78,165,78,166,65,167,79,176,65,177,79,178,79 DATA179,79,180,79,181,79,182,65,183,65,184,79,192,121,193,121 DATA225,83,0,0 RETURN ' PROCEDURE string.index.qsort(switch!,VAR txt$(),index%()) ' *** the index-array has to exist already ' *** if switch!=TRUE, array ascii|() is used LOCAL last,i last=DIM?(txt$())-1 ! index of last element DIM temp$(last) FOR i=0 TO last temp$(i)=txt$(i) NEXT i FOR i=0 TO last index%(i)=i NEXT i IF switch! IF DIM?(ascii|())=0 @initio.ascii.array ENDIF QSORT temp$() WITH ascii|(),last+1,index%() ELSE QSORT temp$(),last+1,index%() ENDIF ERASE temp$() RETURN Thesecondextrapossibilitywithstring-arraysistheuseof'OFFSETo' toignorethefirst'o'charactersduringsorting.Supposeyouhave createdanarrayfiles$()withFILESandwouldliketosortthefilesby length: QSORTfiles$()OFFSET13,n Thefirstcharacter(eitheraspaceor'*')andthefilename(thenext12 characters)arenowignoredduringsorting. üë6.OPERATORSandNUMERICALFUNCTIONS Ç ü\Ç Theoperator'\'(backslash)isidenticaltoDIV: a=b\c Integer-divisionisnotasusefulastheotherinteger-operations,because theresultisaninteger.Ofcourseitis,butthiscaneasilyresultin largeroundingerrors. üPREDandSUCCÇ PRED(i)isfasterthani-1andSUCC(i)isfasterthani+1.Bothfunctions canalsobeusedwithstrings.Notethecleveruse(ahem)ofSUCCinthe followinglinefromtheProcedureTime: MID$(timer$,8)=SUCC(RIGHT$(timer$)) Therightmostdigitoftimer$(alwayseven)isincreasedwithone. üMODÇ Ifyouuseacounterinaloopinordertodosomethingeverytimethe counterreachesamultipleof10,youcoulddothisasfollows: IFcounterMOD10=0 !multipleof10? (...) !yes,dosomething ENDIF Youcouldalsouse: IFMOD(counter,10)=0 (...) ENDIF üBCLRÇ InGFA-Basicversion2.xyouusedANDtoclearabit: x|=x|AND&X11111011 !clearbit2ofthisbyte Remember,thefirst(rightmost)bitisbit0,soabytecontainsbit0-7 fromrighttoleft.InGFA-Basic3.0youclearabitsimplywith: x|=BCLR(x|,2) !clearbit2ofthisbyte Butifyouwanttoclearmorethanonebit,youshouldusetheAND-method: x|=x|AND&X11110000 !clearbit0-3ofthisbyte Inthiscaseyouuseaso-calledmasktoclearcertainbits.Youcanuse ANDalsoasafunction: y|=AND(x|,&X11110000) !evenfasterthanpreviousexample Thiswayyoucantestifabit-mask"fits"avariable: IFAND(x|,mask|) (...) ENDIF Anexampleofthismethod: IFAND(BIOS(11,-1),&X1001) (...) !userpressed<Alternate>+right<Shift> ENDIF üBSETÇ InGFA-Basic2.xyouneededORtosetabit,butnowyouuseBSET: x|=BSET(x|,1) YoustillneedtheOR-methodifyouwanttosetmorethanonebitfast: x|=x|OR&X1010 !setbit1and3 Themask&X1010isusedtosetbits1and3.ComparethiswiththeAND- method,whereê0ÇisusedtoêclearÇabit,whilehereê1ÇisusedtoêsetÇabit. YoucanuseORnotonlyasanoperator,butalsoasafunction: y|=OR(x|,&X1010) üBCHGÇ InsteadofBCHGyoushouldusetheXOR-methodifyouwanttochangemore thanonebit(withamask): x|=x|XOR&X1110 !changebit1-3 XORcanbeusedasafunctionaswell. üLOGÇ Logarithmswithabaseotherthan10orearecomputedasfollows: LOG(x)/LOG(base) üSINQandCOSQÇ IfyouaregoingtoconvertSIN(orCOS)intoSINQ(COSQ),you'llhaveto changefromradialstodegrees.Forexample,youwouldconvertSIN(x)to SINQ(DEG(x)).AlthoughSINQisaboutfivetimesfasterthanSIN,this extracomputationmakesthedifferencealittlelessspectacular.Ifyou arelucky,thevariablealreadyisindegrees,soyoucanuseSINQ immediately.SINQandCOSQshouldnotbeusedifyouneedveryaccurate results,onlyifyouplottheresultandarenotgoingtouseitfor furthercomputations.ExaminethedifferencebetweentheuseofSIN/COS andSINQ/COSQtoseeifthelessaccurateresultisacceptable.InHigh resolutiontrysomethinglikethis: fac#2*PI/639  DRAW0,200 FORx=0TO639 y#=SIN(x*fac#) DRAWTOx,200+y#*200 NEXTx ~INP(2) CLS ' DRAW0,200 FORx=0TO639 y#=SINQ(DEG(x*fac#)) DRAWTOx,200+y#*200 NEXTx ~INP(2) CLS Ç ' fac#=360/639  DRAW0,200 FORx=0TO639 y#=SINQ(x*fac#) DRAWTOx,200+y#*200 NEXTx ~INP(2) üEQVÇ EQVdoesn'tworkproperly.EQV(0,-1)shouldbe0,butequals-65536.The bits16-31arealwaysset:EQVseemstolookatthebits0-15only. üCARDandSWAPÇ Ifa4-byteinteger(postfix%)consistsoftwowords,youcanextract thesewith: low.word=CARD(x%) high.word=CARD(SWAP(x%)) BothwordsareinterpretedasêpositiveÇnumbers. Unfortunately,thereisnoanaloguefunctiontoswapthelowandhigh byteofaword.Thatwouldbeusefulifyouwanttoconvertaword into/fromIntel-format(MS-DOS).Rotating8bitsshoulddothetrick: FUNCTIONintel.word(x%) RETURNCARD(ROR&(x%,8)) !swaplow/highbyte ENDFUNC Nowyoushouldbeabletoextractthelowandhighbyteofaword: low.byte|=BYTE(x) high.byte|=BYTE(@intel.word(x)) üMAXÇ Thisishowyoucouldfindthehighestvalueinaword-array: PROCEDURE max.array(VAR proc(),high) ' *** return highest value of array proc() LOCAL last,n last=DIM?(proc())-1 high=proc(1) !proc(0)ignored FOR n=2 TO last high=MAX(high,proc(n)) NEXT n RETURN Ioftenstorespecialinformationintheelementwithindex0. üCorrelationÇ UsetheProcedureCorrelatetodeterminethecorrelationbetweentwo arrays. üë7.STRINGS Ç üINSTRÇ ThecommandINSTR(a$,b$,i)alwaysreturns'1'ifa$=b$.Fori=1that's fine,butnotfori>1.Don'tblameme,I'mjustthemessenger. üLSETandRSETÇ IfyouuseLSETorRSET,thestringispaddedwithspaces: a$="345" LSETa$="12" PRINTa$ !theinterpreterprints"12",ênotÇ"12345" YoucanuseRSETforrightjustificationofcolumns: f$=SPACE$(10) FORi=1TO10 RSETf$=text$(i) PRINTf$ NEXTi üParserÇ Parsingastring,youwillfrequentlyhavetosplitthestringintothe target$,thestringbeforeandthestringafterthattarget$.The followingfunctionscouldbehelpful: FUNCTION before$(source$,target$) ' *** returns part of source$ before target$ ' *** returns complete source$ if no target$ found LOCAL p p=INSTR(source$,target$) IF p=0 RETURN source$ ELSE RETURN LEFT$(source$,p-1) ENDIF ENDFUNC ' FUNCTION after$(source$,target$) ' *** returns part of source$ after target$ ' *** returns nullstring if no target$ found LOCAL p p=INSTR(source$,target$) IF p=0 RETURN "" ELSE RETURN MID$(source$,p+LEN(target$)) ENDIF ENDFUNC üë8.KEYBOARDINPUT Ç üINKEY$Ç Allkeypressesaresavedinthekeyboard-buffer.Ifyoudon'twantINKEY$ toreadan"old"key,youshouldfirstclearthebuffer: REPEAT UNTILINKEY$="" !clearkeyboard-buffer key$="" REPEAT key$=INKEY$ !waitfornewkey UNTILkey$<>"" Inthefollowingtableyou'llfindafewusefulêdecimalÇASCII-codesyou canuseafter'key$=INKEY$'.InthethirdcolumntheêhexadecimalÇscan-code ofthekeyisalsomentioned(seeparagraph'KEYGET'). êkeyÇ  êASC(key$)Ç êscancodeÇ <Backspace> 8 &H0E <Tab> 9 &H0F <Return>and<Enter>  13 &H1Cand&H72 <Esc> 27 &H01 <Delete>  127 &H53 êkeyÇ êASC(RIGHT$(key$))Ç <F1> 59 &H3B <F10> 68 &H44 <Shift><F1> 84 &H54 <Shift><F10> 93 &H5D <Help> 98 &H62 <Undo> 97 &H61 <Insert> 82 &H52 <ClrHome> 71 &H47 <Leftarrow> 75 &H4B <Rightarrow> 77 &H4D <Uparrow> 72 &H48 <Downarrow> 80 &H50 Keysinthesecondpartofthistablereturna2-bytevalueafterINKEY$. Youonlyneedthelowbyte,thehighbyteis&H00.That'swhyaStandard Globallikehelp$isdefinedas'CHR$(0)+CHR$(98)'.Thenit'seasyto checkif<Help>waspressed: IFkey$=help$ (...) !<Help> ENDIF Otherwise,youhavetotestasfollows: IFASC(RIGHT$(key$))=98 (...) !<Help> ENDIF However,readtheparagraph'KEYGET'fortheultimatekeypress-processor. ÇIfyouarejustwaitingforanykeypress,youcoulduseeitherofthe followingmethods(clearthekeyboard-bufferfirst): ~INP(2) !myfavourite ' KEYGETcode% !perhapsthisisclearerinalisting ' REPEAT !aloopisalsopossible UNTILLEN(INKEY$) ThelattermethodisneededifyouarewaitingforanykeypressêorÇany mouse-click: REPEAT UNTILLEN(INKEY$)ORMOUSEK üINPUTÇ Ifyoudon'twantthequestionmarktoappearafterINPUT,use: LOCATEcol,lin INPUT"",txt$ Thenullstringandthecommaareessential.Mostofthetimeyou'llneed somethinglike: LOCATEcol,lin INPUT"Enteryourname:",name$ Butiftheinstruction-lineisnotthesameastheINPUT-line,use: PRINTAT(col1,lin1);"Enteryourname:" LOCATEcol2,lin2 INPUT"",name$ AfterINPUT,theusercanpress<Insert>toswitchbetweenInsert-modeand Overwrite-mode.Ihavenotbeenabletodiscoverhowtoinputcharacter- codes0-31afterINPUT.It'snotimportantanyway,butIreadsomewhere youcoulduse<Alternate>forthispurpose.TheAlternate-methodcanbe usedforcharacter-codes128-255(not127).Inthefollowingtableyou'll findsomeimportantcharacterswiththedecimalASCII-code:ê Ç êcharacterÇ êASCII-codeÇ êcharacterÇ êASCII-codeÇ êcharacterÇ êASCII-codeÇ á - 160 é - 130 í - 161 à - 133 è - 138 ì - 141 ä - 132 ë - 137 ï - 139 â - 131 ê - 136 î - 140 ó - 162 ú - 163 ÿ - 152 ò - 149  ù - 151 ß - 158 Ö - 148  ü - 129 ô - 147 û - 150 α - 224  ≡ - 240  ½ - 171 β - 225  ± - 241  ¼ - 172 δ - 235  ≥ - 242  ² - 253 µ - 230  ≤ - 243 π - 227  ÷ - 246 τ - 231  ≈ - 247 Ç ¢ - 155  © - 189 £ - 156  § - 221 ƒ - 159 IfyouwanttouseoneofthesecharactersafterINPUT,youshouldhold <Alternate>down,enterthecode,andrelease<Alternate>.Ihopeyour printer-drivercoulddigestthistable... Youcanuse<Backspace>,<Delete>,<Leftarrow>and<Rightarrow>onan INPUT-line,butalso: <Uparrow> -cursortostartofinput-line <Downarrow> -cursortoendofline <Esc> -eraseline Thefirsttwofeelslightlyunnatural,Iwouldpreferittheotherway:up toend,downtostart. BothINPUTandLINEINPUTuseaspecialcursor,soitdoesn'tmakemuch sensetouseXBIOS21(Curscon)todosomethinginterestingwiththeTOS- cursor. üINPUT$ Ç Fortheinputofasecretpassword,youcouldusesomethinglike: PRINT"typepassword(5characters):"; code$=INPUT$(5) Thepassworddoesnotappearonthescreen. ü LINEINPUTÇ LINEINPUTusestheunderscore(_)asthecursorinawindow.Afteryou press<Return>,theunderscoreisnotcompletelyerased.Therightmost pixelremainsvisible.IthinkthisisaGEM-bug. üKEYTESTÇ TheKEYTEST-functiondoesnotrespondtokeyssuchas<Help>,<Undo>,etc. üKEYGETÇ KEYGETwaitsforakeypress,justlikeINP(2).ButKEYGETisfarmore flexible,becauseitreturnstheASCII-codeêandÇthescan-codeofanykey êandÇalsothestateofthespecialkeys<Shift>,<Control>,<Alternate>and <CapsLock>.ConsultyourmanualfortablesofASCII-codesandscan-codes (intheparagraph'INKEY$'youalreadyencounteredsomeimportantcodes). Studythefollowingexampletogetanimpressionoftheeasywayyoucan examineallkeypresseswithKEYGET: Ç @initio_keyget!assignvariablestothethreecodes ' DO KEYGETget_code% @keyget!processkeypressthere(notincluded) LOOP ' PROCEDUREinitio_keyget ABSOLUTEascii|,V:get_code%+3 ABSOLUTEscan|,V:get_code%+1 ABSOLUTEstatus|,V:get_code% RETURN YouwillhavetowriteyourownKeyget-Procedure.Youcancheckifanyof thespecialkeyshasbeenpressed,byusingBTST(status|,bit): bit0=Right<Shift> bit1=Left<Shift> bit2=<Control> bit3=<Alternate> bit4=<CapsLock> Youcoulddiscoveriftheuserhadpressed<Control><Downarrow>with: IFscan|=&H50ANDBTST(status|,2) (...) ENDIF IfyouareêonlyÇinterestedinmonitoringthefivespecialkeys,youcould useBIOS11(Kbshift)aswell: status|=BIOS(11,-1) Usethesametableasabovetotestifbit0-4isset. Youareadvisedtoclearthekeyboard-bufferbeforeleavingtheProcedure Keyget. Inmostcasesthescan-codeofakeyisthesame,whetheryoupresseda specialkeysimultaneouslyornot.Butwatchoutforthefollowing exceptions!For<Shift><F1>to<Shift><F10>thescan-codes&H54to&H5D arereturned(ênotÇ&H3Bto&H44).OnanMS-DOScomputerthesecodesare usedforthekeysF11toF20.Thecombinations<Control><LeftArrow> (&H73)and<Control><RightArrow>(&H74)alsohavespecialcodes.Blame MS-DOS.Thecombinations<Alternate><1>to<Alternate><=>havethe specialcodes&H78to&H83.That'sALT1toALT=forMS-DOS. üKEYLOOKÇ Accordingtoanunconfirmedreport,KEYLOOKdoesnotfunctionproperly withthepre-BlitterTOS. ü üKEYPRESSÇ KEYPRESSusesthesame4-byteformatasKEYGET:&Hccss00aa.Inityou willrecognizetheASCII-code(&Haa),thescan-code(&Hss)andthecode forthespecialkeys(&Hcc).Ifyouwanttosimulatethepressingofakey inanAlertbox,youwillhavetosendboththeASCII-codeandthescan- code.Use&H1C000Dtosimulatethepressingof<Return>.Or&H04620062for <Control><Help>,althoughthatcertainlywon'thelpinanAlertbox.If youdon'tneedthescan-code(e.g.withINPUT),youcanusejustKEYPRESS &Haa. ü KEYDEF ÇTheeditoralwaysusesKEYPAD&X101110,soyouwillhavetosetbit4 yourself(e.g.KEYPAD&X10000)beforeyouwillbeabletouseKEYDEFin yourprogram. üKeyboard Ç AsfarasIknow,therearefourdifferentkeyboardsavailable:USA (QWERTY),English(QWERTY),German(QWERTZ)andFrench(AZERTY).Thekey withscan-code&H2B(totherightof<Return>)hasadifferentASCII-code ineachversion: êversionÇ êASCII-codeÇ êcharacterÇ USA &H5C (92)  \ English &H23 (35)  # German &H7E (126)  ~ French &H40 (64)  @ YoucoulduseXBIOS16(Keytbl)todeterminethekeyboard-version: PROCEDURE keyboard.version SELECT PEEK(LPEEK(XBIOS(16,L:-1,L:-1,L:-1))+&H2B) CASE &H5C usa.keybrd!=TRUE CASE &H23 english.keybrd!=TRUE CASE &H7E german.keybrd!=TRUE CASE &H40 french.keybrd!=TRUE ENDSELECT RETURN Youshouldtakeintoaccountthedifferencesbetweenthekeyboard-versions ifyouarewritingaprogramthatshouldrunsmoothlyinanycountry. ÇInthefollowingtableIhavegatheredallkeysthathaveênotÇthesame meaningonthefourkeyboard-versions: êscancodeÇ êUSAÇ êEnglishÇ  êGermanÇ êFrenchÇ  &H0C - - ß )  &H0D = = - '  &H10 Q Q Q A  &H11 W W W Z  &H15 Y Y Z Y  &H1A [ [ Ü [  &H1B ] ] + ]  &H1E A A A Q  &H27 ; ; ö M  &H28 ' ' Ä \  &H29 ` ` # `  &H2B \ # ~ @  &H2C Z Z Y W  &H32 M M M ,  &H33 , , , ;  &H34 . . . :  &H35 / / - =  &H60 none  \ < < Ifyouaregoingtouseanyscan-codefromthistable,youshouldbevery careful.It'snotnicetoaskaGermanusertopress<Y>,buttestfor scan-code&H15inyourprogram... Ifyouinsistondoingthingsthehardway,youcanfindtheASCII-value thatisassignedtoakeywithXBIOS16.Actuallytherearethreetables: oneforanormalkeypress,oneforashiftedkeyandoneforakeypress withCapsLockon: keytbl%=LPEEK(XBIOS(16,L:-1,L:-1,L:-1)) shift%=keytbl%+&H80 capslock%=shift%+&H80 NowyoucanfindtheASCII-codeforanyscan-code(<&H80): ascii=PEEK(keytbl%+scancode) !normalkey ascii=PEEK(shift%+scancode) !shiftedkey ascii=PEEK(capslock%+scancode) !CapsLockon üKeyclick,KeyrepeatandCapsLockÇ Normally,youneedtheKeyclickasanaudiblefeedback.Sometimesyouhave toswitchtheKeyclickoff,e.g.whileanXBIOS32songisplaying: PROCEDURE key.click(switch!) IF switch! SPOKE &H484,BSET(PEEK(&H484),0) ! keyclick on ELSE SPOKE &H484,BCLR(PEEK(&H484),0) ! keyclick off ENDIF RETURN ÇIfyourprogramreactsslowlyafterakeypress,youprobablyhaveto switchtheKeyrepeattemporarilyoff: PROCEDURE key.repeat(switch!) IF switch! SPOKE &H484,BSET(PEEK(&H484),1) ! key-repeat on ELSE SPOKE &H484,BCLR(PEEK(&H484),1) ! key-repeat off ENDIF RETURN YoucanswitchCapsLockonoroffwith: PROCEDURE caps(switch!) IF switch! ~BIOS(11,BSET(BIOS(11,-1),4)) ! CapsLock on ELSE ~BIOS(11,BCLR(BIOS(11,-1),4)) ! CapsLock off ENDIF RETURN üë9.SCREENOUTPUT Ç üPRINTÇ ItisveryimportanttoknowifPRINTwillbeusedontheso-calledTOS- screen(nowindowsopened),orinawindow.TOSemulatestheVT52-terminal ofDigitalEquipment,soifyouPRINTontheTOS-screen,theVT52-codes willbeinterpretedascommands.Butinawindowthesecodesareprinted ascharacters! InbothHighandMediumresolutionyoucanPRINT25linesof80 characters,butinLowresolutionit's25linesof40charactersonly. Normallyyoucan'tPRINTacharacteratposition(80,25)inHighorMedium resolution,orat(40,25)inLowresolution.Trythefollowing: PRINTAT(80,25);"X"; andyouwillseethatalinefeedisexecutedautomatically,inspiteof thesemicolonafter"X".OntheTOS-screenyoucanputacharacteratthis positionbyusingtheVT52-command'wrapoff': PRINTAT(80,25);"*wX"; !usetheEscape-characterinsteadof* After'Escw'thelinefeedissuppressed.Theeasiestwaytoenterthe Escape-characterintheGFA-editoristohold<Alternate>downandthento enter<2><7>.IfyouPRINTastringthatdoesn'tfitonthecurrentline, theremainingcharactersareeitherprintedonthenextline('Escv',the defaultintheinterpreter,ênotÇinacompiledprogram),ordiscarded ('Escw').Actually,after'Escw'allcharactersuptothefirstCHR$(10) orCHR$(13)arediscarded. It'simpossibletoPRINTcharacterswithASCII-code0-31ontheTOS- screen.However,youcanprintanycharacterwith: OUT5,code Ifnecessary,useLOCATEfirst. Afteropeningawindow(OPENWx)thecommandDEFTEXTwillchangesizeand colourofPRINTedtextaswell!OneadvantageisthatyoucannowPRINTin differentcoloursonthescreen. OntheTOS-screen,allPRINTedtexthasthesamecolour.Thiscolouris determinedbycolour-index1andisalsousedfortheAlert-boxandthe Fileselector.Thebackgroundonthescreenisdeterminedbycolour-index 0.ThiscolourisusedafterCLS. ItispossibletoPRINTindifferentcoloursontheTOS-screen,byusing theVT52-code'Escb'.ThebackgroundofPRINTedtextcanbechangedwith VT52-code'Escc'.Usethefollowingfunctionstoexperiment: DEFFNink$(color)=CHR$(27)+"b"+CHR$(color) DEFFNpaper$(color)=CHR$(27)+"c"+CHR$(color) Usethecolour-tablefromtheparagraph'SETCOLOR'orbepreparedto becomeveryfrustrated.IusetheStandardArraycolor.index()asthe colour-tableinmyprograms,soIchangethecolourofthePRINTedtextor theback-groundwiththeStandardFunctions: DEFFNink$(color)=CHR$(27)+"b"+CHR$(color.index(color)) DEFFNpaper$(color)=CHR$(27)+"c"+CHR$(color.index(color)) ÇRemember,theVT52-codeshavetobePRINTedtobecomeeffective,like this : PRINT@ink$(red);@paper$(green);"thistextiseye-catching" Notethespacesatbeginningandendofthestringtoemphasizethetext- colouragainstthebackground-colour.Ofcourseyouhavetodeclarethe variablesredandgreenfirst(usuallycolour-index2and3;orifyou don'tusetheVDIcolour-index,trythenumbers1and2).Idefinethe defaultcoloursasStandardGlobalsinmyprograms.BeforeIforget,it won'tworkinHighresolution.Sorry,couldn'tresistthatone. InordertocatchtheeyeoftheuserinHighresolutionyoucanPRINT reverseontheTOS-screen: PRINT"thisis*pIMPORTANT*q" !enterEscinsteadof* EntertheEscape-characterintheusualway.Noteagaintheextraspace bothbeforeandafterthewordthatshouldstandout.Ofcourseyoucould alsouseCHR$(27): PRINT"thisis";CHR$(27);"pIMPORTANT";CHR$(27);"q" Moredifficulttoreadonthescreen,buteasiertoLlist.Iusethe StandardFunctionRev$inallprograms: DEFFN rev$(txt$)=CHR$(27)+"p"+txt$+CHR$(27)+"q" IfyouuseacommawithPRINT,thecursorwilljumptothenexttabulator- stop.Tab-stopsareatposition1,17,33,49and65.Trythefollowingto seewhatImean(inHighorMediumresolution): PRINT"1","17","33","49","65","1","17" Ifyouusethecommaafterthelasttab-stop,alinefeedisexecutedand thecursorjumpstothefirsttab-stoponthenextline. Theeasiestwaytousedoublequotesisbyusingdoubledoublequotes (readthistwicetomakesureyouunderstandit): PRINT"doublequotesprintedthe""easy""way" InaDATA-lineasingledoublequotesuffices: DATA"lookMa,"doublequotes"again" Or,simply: DATAlookMa,"doublequotes"again TrytheProcedureFastprintinHighresolutionifyoufindPRINTtooslow. ThisProcedureprintsaboutfourtimesfaster!VT52-commandsareignored, becausecharactersarecopiedstraightfromthefont-tabletothescreen. üLOCATEÇ ThesyntaxofPRINTATandLOCATEisnowlessconfusing: PRINTAT(column,line) LOCATEcolumn,line InolderversionsofGFA-BasicitwasLOCATEline,column.Checkthisif yourunanoldprogramandtextisPRINTedonthewrongplace. üPRINTTABÇ PRINTTABbehavesstrangelyifthepositionisgreaterthan80.Trythe followinginHighorMediumresolution: FORi=0TO30 PRINTTAB(i*20);i; NEXTi Onewaytosolvethisproblemis: PRINTTAB(MOD(i*20,80));i; !dousesemicolons ButIthinkthisisaGFA-bugthatprobablywillbecorrectedinfuture versions. YoucancombineTABwithPRINTATandwithPRINTUSING: PRINTAT(1,1);"1";TAB(40);"40" PRINTTAB(40);USING"##",40 üSetscreen(XBIOS5) ÇWithXBIOS5(Setscreen)itispossibletochangetheresolutionfromLow toMediumandfromMediumtoLow.Unfortunately,GEMignorestheswitch, soGEM-commands(e.g.ALERT,TEXT,MOUSE)donotworkproperly!Butyou couldchangefromLowtoMediumresolutiontoshowtextontheTOS-screen withPRINT(andVT52-commands).Mostuserswillbegratefulforthe improvedreadabilityofthetext: ~XBIOS(5,L:-1,L:-1,1) !switchfromLowtoMedium (...) !printtextinMediumresolution ~XBIOS(5,L:-1,L:-1,0) !andgobacktoLow Ifyouchangetheresolution,theVT52-emulatorisautomatically initialised.You'llprobablyhavetoadjustthepalettebeforeyoucan readthetextwithoutsun-glasses.Don'tforgettosaveandrestorethe oldpalette. XBIOS5isveryusefulifyouwouldliketodrawonascreenbefore showingittotheuser.Drawingonan"invisible"screenisindeed possible,becausetheoperatingsystemusestwoscreens:thephysical screen(visibleonyourmonitor)andthelogicalscreen(usually,butnot necessarily,thesameasthephysicalscreen).Allgraphical(GEM-)com- mands,includingtheTEXT-command,arealwayssenttothelogicalscreen. ButTOSwillsendPRINT-commandstotheêphysicalÇscreen,unlessyou've openedawindow!Iftheaddressoflogicalandphysicalscreenisnotthe same,youhaveyourinvisiblescreen(exceptforPRINTingontheTOS- screen).TheaddressofthelogicalscreenêmustÇbeamultipleof256. StudytheProceduresInitio.logical.screen,Swap.screenand Restore.physical.screentoseehowyoucouldusethedescribedmethodfor animation: PROCEDURE initio.logical.screen ' *** global : SCREEN.1% SCREEN.2% DIM screen.2|(32256) screen.2%=VARPTR(screen.2|(0)) screen.2%=screen.2%+256-(screen.2% MOD 256) screen.1%=physbase% ~XBIOS(5,L:screen.2%,L:-1,-1) ! invisible screen.2 is now active RETURN Ç ' PROCEDURE swap.screen ' *** physical and logical screen are swapped SWAP screen.1%,screen.2% VSYNC ! avoid flash ~XBIOS(5,L:screen.2%,L:screen.1%,-1) ! swap the screens RETURN ' PROCEDURE restore.physical.screen ~XBIOS(5,L:physbase%,L:physbase%,-1) RETURN OnsomeST-computersXBIOS5doesnotfunctionproperlyafterinstallation ofaRAM-disk.Inthatcaseyoucouldchangetheaddressofthelogical screenwith: VSYNC  SLPOKE&H45E,adr% üFontÇ TOShasthreebuilt-insystem-fonts.ThedefaultPRINT-fontforHigh resolutionisthe8x16font(equalsDEFTEXT,,,13forTEXT),whilethe8x8 font(equalsDEFTEXT,,,6)isusedinMediumandLowresolution.Youcan switchbetweenthesetwofontswiththefollowingProcedures: PROCEDURE font.8x16 LOCAL a$,adr% a$=MKI$(&HA000)+MKI$(&H2009)+MKI$(&H4E75) adr%=VARPTR(a$) adr%=C:adr%() ! address of font-table {INTIN}={adr%+8} ! pointer to 8x16 system-font VDISYS 5,2,0,102 RETURN ' PROCEDURE font.8x8 LOCAL a$,adr% a$=MKI$(&HA000)+MKI$(&H2009)+MKI$(&H4E75) adr%=VARPTR(a$) adr%=C:adr%() ! address of font-table {INTIN}={adr%+4} ! pointer to 8x8 system-font VDISYS 5,2,0,102 RETURN BothProceduresseemtohaveproblemswiththeaccessoryQUICKST,butI neveruseitwithGFA-Basicbecausethereareotherproblems(INPUT)as well.IfIdon'tuseit,howdidIdiscoverthis?Goodquestion.Thethird fontisusedforicons,butforsomereasoncannotbecomethecurrent system-font.TheVDI-functionseemstoworkonlywithfontscontaining charactersofwidth8pixels.Thefunctionisnotofficiallydocumented byAtari(?). ÇYoucanreplacethesystem-fontbyafontthathasbeencreatedwith FONTKITbyJeremyHughes(4114byteA1_xxxxx.FONfileforHigh resolution).UsetheProcedureChange.fontforthispurposeandcallthe ProcedureNormal.fonttorestoretheoriginalsystem-font: PROCEDURE change.font ' *** global : NEW.FONT! NORMAL.FONT% LOCAL adr%,new.font% ' ' *** load A1_xxxxx.FON file (4114 bytes) here INLINE new.font%,4114 ' adr%=L~A-22 normal.font%={adr%} SLPOKE adr%,new.font% new.font!=TRUE RETURN ' PROCEDURE normal.font IF new.font! SLPOKE L~A-22,normal.font% new.font!=FALSE ENDIF RETURN IhavenotyetdiscoveredhowtouseaFONTKIT-fontwithTEXT.Yes,I couldloadanewfontafterinstallingGDOS,butthat'snotwhatI'm lookingfor.Isthereaquickandnot-dirtywaytoconvinceGEMthatanew fonthasbeeninstalled? Afont-tableforthe8x16fontoccupies4096bytes(16bytes/character, 256characters).AFONTKIT-fontusuallyhasanameattachedattheend, that'swhyIreserve4114bytes.TOSignoresthenamecompletely,it's onlyusedbytheaccessoryFONSEL.ACC.Youcanloadany4096-bytefontin theProcedureChange.font,youdon'tevenhavetochange4114into4096. Althoughyoulose18bytesifyoudon't. üë10.PRINTER Ç üPrinterreadyÇ Ifyousenddatatoyourprinter(HARDCOPY,LPRINT,etc.),yourSTwill wait30looooooongsecondsiftheprinterhappenstobenotready.Always checkiftheprinterisreadybeforesendingdatatotheprinter,e.g.by callingthefollowingProcedure: PROCEDUREprinter.ready LOCALk DO EXITIFGEMDOS(17) ALERT3,"printer||notready!!",1,"OK",k LOOP RETURN üHARDCOPYÇ YoucansendascreendumptotheprinterbyusingthecommandHARDCOPYor bypressing<Alternate><Help>.InêbothÇcasesyoucanabortthescreendump bypressing<Alternate><Help>. YoucanuseCONTROL.ACCtochangetheprinter-parameters.Don'tforgetto savethedesktop,inordertostoretheseparametersinthefile DESKTOP.INF.Lookfor'#b'withyourdisk-editorifyou'recurious.The parameterswillonlybereadfromDESKTOP.INFifCONTROL.ACCisinstalled afterareset!IsuggesttheuseofXBIOS33(Setprt)inaprograminstead ofusingCONTROL.ACC.ForascreendumpfromtheHighresolutionscreento anEpson-compatibleprinter,clearbit1andsetbit2: PROCEDUREscreendump ~XBIOS(33,&X100) !screendumptoEpson(-compatible)printer HARDCOPY RETURN Ifyousetbit2,TOSassumesyouconnectedanEpson-printer(960 pixels/line).Clearbit2andTOSassumesyouhaveanAtari-printer(1280 pixels/line). IfyouuseHARDCOPY,thewidth/heightratiooftheprintoutdoesnot correspondwiththatofthescreen.Forareasonablyfast1:1screendump, studytheProcedureHigh.screendump.epson(EpsonFX-80,orother9-pin Epson-compatibleprinter)ortheProcedureHigh.screendump.star24(24-pin StarLC24-10): PROCEDURE high.screendump.star24 LOCAL m$,b$,k,scrn.start%,col,b%,x,d%,p|,b1|,b2|,b3|,n  lf$=CHR$(10)  ff$=CHR$(12)  DEFFN bit.image$(m,d)=CHR$(27)+"*"+CHR$(m)+CHR$(MOD(d,256))+ CHR$(d/256)  DEFFN line.space$(n)=CHR$(27)+"3"+CHR$(n)  initialize$=CHR$(27)+"@"  scrn.start%=XBIOS(2)  ' Ç  LPRINT initialize$;  FOR col=0 TO 79  b%=scrn.start%+col  LPRINT SPC(8);  LPRINT @line.space$(24);  LPRINT @bit.image$(33,800);  FOR x=399 TO 0 STEP -1  d%=ADD(b%,MUL(x,80))  p|=BYTE{d%}  IF p|=0  OUT 0,0,0,0,0,0,0  ELSE  CLR b1|,b2|,b3|  IF BTST(p|,0)  b1|=7  ENDIF  IF BTST(p|,1)  ADD b1|,56  ENDIF  IF BTST(p|,2)  ADD b1|,192  b2|=1  ENDIF  IF BTST(p|,3)  ADD b2|,14  ENDIF  IF BTST(p|,4)  ADD b2|,112  ENDIF  IF BTST(p|,5)  ADD b2|,128  b3|=3  ENDIF  IF BTST(p|,6)  ADD b3|,28  ENDIF  IF BTST(p|,7)  ADD b3|,224  ENDIF  OUT 0,b3|,b2|,b1|,b3|,b2|,b1|  ENDIF  NEXT x  LPRINT  EXIT IF INKEY$=esc$  NEXT col LPRINT ff$;  LPRINT initialize$; RETURN Foramoreflexibleapproach,studytheProcedureDegas.screendump(Star LC24-10,possibleformats:27x17,18x11,13.5x8.5or9x5.5cm). ÇItshouldbepossibletosendonlya(GET-)rectangletoyourprinterwith XBIOS36(Prtblk)orV_OUTPUT_WINDOW(VDI5,Escape21).Anybodyoutthere whoknowshow? Never,Irepeat,êneverÇswapdisksduringascreendump,asthiscouldbe fatalforthenewdisk.TOSignoresthewrite-protectstateduringa screendump,soitwillmissthedisk-swapcompletely.TOSwillusetheold FATforthenewdisk,andthatusuallyisfatal(nopunintended). IfyouhaveinstalledaGFA-Basicprinter-driver(e.g.PTEPSON.PRG),a screendumpseemstobeimpossible.Thebit-imagemodeoftheprintercan't beusedafterthedriverhasbeeninstalled. üPrinter-commandsÇ Mostmatrix-printersrecognizeeitherIBM-orEpson-commands(orboth).I usethefollowingProceduretodefinethemostimportantprinter-commands formyStarLC24-10.Adaptthedefinitionstoyourownprinter,butstick tothenamesfortheglobalvariablesandfunctions.Otheruserscould thenuseyourprogramseasilyafterreplacingtheProcedureInitio.printer withtheirown: PROCEDURE initio.printer ' *** initializes global printer-variables for Star LC24-10 ' *** DIP-switch settings : ' 1-1 OFF 2-1 ON ' 1-2 ON 2-2 ON ' 1-3 OFF 2-3 ON ' 1-4 ON 2-4 ON ' 1-5 ON 2-5 OFF ' 1-6 ON 2-6 OFF ' 1-7 ON 2-7 ON ' 1-8 ON 2-8 ON ' LOCAL c$,f$ c$=CHR$(27) f$=CHR$(28) ' draft.char$=c$+"x0" lq.char$=c$+"x1" ' courier.style$=c$+"k0"+lq.char$ prestige.style$=c$+"k2"+lq.char$ orator.style$=c$+"k3"+lq.char$ script.style$=c$+"k4"+lq.char$ ' normal.char$=c$+"q0" outlined.char$=c$+"q1" shadow.char$=c$+"q2" outlined.shadow.char$=c$+"q3" ' italic.on$=c$+"4" italic.off$=c$+"5" ' Ç emphasized.on$=c$+"E" emphasized.off$=c$+"F" ' underline.on$=c$+"-1" underline.off$=c$+"-0" ' bold.draft$=draft.char$+emphasized.on$+double.on$ bold.lq$=lq$+double.on$ bold.off$=emphasized.off$+double.off$ ' superscript.on$=c$+"S0" superscript.off$=c$+"T" subscript.on$=c$+"S1" subscript.off$=c$+"T" ' epson.set$=c$+"t0" ibm.set$=c$+"t1"+c$+"6" DEFFN special.on$(n)=c$+"\"+CHR$(MOD(n,256))+CHR$(DIV(n,256)) DEFFN ibm.special$(n)=c$+"^"+CHR$(n) DEFFN epson.special$(n)=ibm.set$+@ibm.special$(n)+epson.set$ ' pica$=c$+"P" ' elite$=c$+"M" ' condensed.on$=CHR$(15) condensed.off$=CHR$(18) ' large.on$=c$+"W1" large.off$=c$+"W0" large.line$=CHR$(14) ' courier.proportional$=courier.style$+c$+"p1" prestige.proportional$=prestige.style$+c$+"p1" proportional.off$=c$+"p0" ' DEFFN master.mode$(n)=c$+"!"+CHR$(n) underline=128 italic=64 expanded=32 LET double.strike=16 emphasized=8 condensed=4 proportional=2 elite=1 ' normal.size$=c$+"h"+CHR$(0) LET double.size$=c$+"h"+CHR$(1) quad.size$=c$+"h"+CHR$(2) LET double.height$=c$+"w1" normal.height$=c$+"w0" normal.width$=f$+"E"+CHR$(0) LET double.width$=f$+"E"+CHR$(1) triple.width$=f$+"E"+CHR$(2) Ç ' lf$=CHR$(10) DEFFN lf$(n)=c$+"f1"+CHR$(n) rev.lf$=c$+CHR$(10) ' ff$=CHR$(12) rev.ff$=c$+CHR$(12) ' justify.left$=c$+"a0" justify.right$=c$+"a2" justify.full$=c$+"a3" center$=c$+"a1" ' reset$=c$+"@" ' RETURN Ofcourseyoucoulddeleteallvariablesyoudon'tneedinyourprogram. Anditreallywouldbeniceifeveryoneusestheproposednames.Oneof thestrongpointsofPublicDomainGFA-programsisthatit'seasytoadapt aprogram.Orrather,itshouldbeeasy.UsingtheaboveProcedureisone stepintherightdirection. üë11.FILES Ç üFloppyWriteTestÇ YouareadvisedtoswitchtheWriteVerifytestoff: SPOKE&H444,0 !testoff SPOKE&H444,1 !teston(default) AccordingtoexpertslikeDaveSmallandBillWilkinsontheVerifytestis acompletewasteofvaluabletimeifyouwritetoadisk. üStepRateÇ Youwillfindthecurrentstep-rateofyourdrivewith: PRINTDPEEK(&H440) Thefollowingvaluesarepossible: 0-6ms 1-12ms 2-2ms 3-3ms(default) Theoperatingsystemonlylooksatthisvalueafterareset(?).Foran external5.25"-driveyouprobablyhavetouse12ms. üRAM-disk Ç DriveDisoftenreservedforaRAM-disk.GFAwillrecognizeaRAM-disk withDFREE(4)onlyifitwasalreadypresentatthetimetheinterpreter wasloaded. Afterswitchingoffyour1040STyoushouldwaitatleast15seconds beforeswitchingonagain.OtherwiseanoldRAM-disk(orsomethingelsein RAM,e.g.avirus...)maystillbepresentwhenyouswitchyourcomputer onagain. IfaRAM-diskisnotinstalledproperlyafterareset,thereasoncouldbe hiddeninthedrivebit-tableat&H4C2.TheoldTOSdoesnotclearthis tableandaRAM-diskcanonlybeinstalledasdriveDifbit3iscleared. Bytheway,usedriveC(bit2)êonlyÇforaharddisk. üDIR$()Ç UseGEMDOS25(Dgetdrv)tofindthecurrentdriveandcombinethiswith DIR$(drive)tofindthecurrentpath: drive=GEMDOS(25) !drive0-15 drive$=CHR$(65+drive) !driveA-P p$=DIR$(drive+1) IFp$="" path$=drive$+":\" !maindirectory ELSE path$=drive$+":"+p$+"\" ENDIF ÇWithDIR$(0)you'llfindthepathoftheêcurrentÇdrive,notnecessarily driveA.DIR$(1)returnsthepathofdriveA.GEMDOSremembersthelast usedpathforallavailabledrives.SeealsotheStandardProcedure Get.path. IfyourunGFA-BasicfromthemaindirectoryandloadaGFA-programfroma folder,DIR$(0)willreturnthenullstring(""),notthefolder.After usingCHDIRwiththefolder-name,thecorrectpathwillbereturned.Iuse CHDIRintheShell-programs,sotheStandardGlobaldefault.path$will containthepathoftheGFA-program.Thismakeslifeeasierifyouwantto loaddata-filesfromthesamefolder,butdon'tknowtheprecisepathwhen youwritetheprogram.Itwouldbeniceifyoucoulddeterminethepathof therunningGFA-programintheprogramitself. Youcanmakeanarray-tableofavailabledriveswiththeaidofBIOS10 (Drvmap): DIMdrive!(15) SELECTDPEEK(&H4A6) CASE1 drive!(0)=TRUE CASE2 drive!(0)=TRUE drive!(1)=TRUE ENDSELECT table%=BIOS(10) FORn=2TO15 IFBTST(table%,n) drive!(n)=TRUE ENDIF NEXTn Youcancheckifaharddiskisconnectedwith: IFPEEK(&H472)<>0 harddisk!=TRUE ENDIF üDIRÇüandFILESÇ AfterDIR,FILES,TRONorDUMPyoucanslowdownthescrollingwith <CapsLock>.Youcantemporarilystopthescrollingbyholdingdownthe right<Shift>-key.TheoutputafterDIRfitsonanyscreen,buttheFILES- outputistoowideforLowresolution.DIRwillshowonlyêfilesÇinthe currentdirectory.FILESwillalsoshowêfoldersÇ(markedwith*).WithDIR (andFILESELECT)youwillnotbeabletosee"hidden"filesor"system" files,butFILESwillshowallfiles.Youcanalsosearchforhidden and/orsystemfileswithFSFIRSTandFSNEXTbysettingbit1and/orbit2 oftheattribute-byte. PerhapsyouhavenoticedthatafterthecommandFILESthefirsttwolines arepeculiarifyouhappentobeinafolder.Thefirst"name"inafolder isalways'.'(onedot)andthesecondalways'..'(twodots).Timeand dateareincorrect,becausetheauthorsof(theold)TOSforgottoconvert thesetoMS-DOSformat.Incaseofnestedfolders,theoperatingsystem Çfindstheprecedingfolderthroughapointerofthe'..'-file.That'swhy youcanuse'CHDIR..'toreturntotheprecedingfolder.Don'ttrythis inthemaindirectory,oryou'llgetanerror. üFSFIRSTandFSNEXTÇ TheDTA-bufferisusuallyfoundatBASEPAGE+128(it'salwaysthereafter start-up),butyoushouldnotcountonit.UseFGETDTA()tofindthe currentaddress,beforeFSFIRST: dta.adr%=FGETDTA() e%=FSFIRST(format$,attr) FSFIRSTreturns-33ifnofilehasbeenfound.FSNEXTreturns-49ifno morefilesarefound. Inanaccessoryit'ssafertocreateanewDTA-buffer: old.dta%=FGETDTA() !oldbuffer dta$=STRING$(44,0) dta.adr%=V:dta$ ~FSETDTA(dta.adr%) !newbuffer (...) !FSFIRST/FSNEXT ~FSETDTA(old.dta%) !restoreoldbuffer TheDesktopwillappreciateallthisextrawork. The44byteDTA-buffer(DataTransferAddress)containsthefollowingdata afterasuccesfulFSFIRSTorFSNEXT: êoffsetÇ  0-20 -reserved  21 -attribute-byte 22-23 -time 24-25 -date 26-29 -file-length 30-43 -filename(includingtheextension,terminatedby&H00) Theattributesandthefilenamecanbereadfromthebufferwith: attr=BYTE{dta.adr%+21} file$=CHAR{dta.adr%+30} TheDTA-bufferisnotanexactcopyoftherelevantinformationinthe directoryofthedisk.Withadisk-editoryouwouldfindaslotof32 bytesforeachfileorfolder: êoffset Ç 0-7 -file-orfolder-name(withoutextension) 8-10 -extension 11 -attribute-byte 12-21 -reserved 22-23 -time 24-25 -date 26-27 -FAT-pointer 28-31 -file-length ÇThefirstbyteofthefilenamehasaspecialmeaninginthefollowing cases: &H00 -freeslot,neverusedbefore &HE5 -erasedfile,nowfreeslot &H2E -subdirectory BothtimeanddatearestoredinMS-DOSformat.ConsultyourGFA-manual formoreinformation.TheFAT-pointer,alsoinanMS-DOSformat(Intel- format :firstlowbyte,thenhighbyte),pointstothefirstclusterof thefile.Ifyouarelookingatafolder,theFAT-pointerpointstothe clusterwhereyouwillfindthedirectoryofthisfolder(subdirectory). Ifyouarelookingatasubdirectory(i.e.youareêinÇafolder),thefirst twoslotsarereservedforthefiles'.'and'..'(&H2Eand&H2E2E).This hasalreadybeenmentionedintheparagraph'DIRandFILES'.Finally,the file-lengthisstoredin,youguessedit,MS-DOSformat.Youmightwonder whatMS-DOShastodowithAtari-disks.Readtheparagraphs'DiskFormat' and'FileAllocationTable'fortheexplanation. Ifyouusetheattribute-byte&X10000youwillfindbothfoldersêandÇ files!Ifthefoldersinadirectorydon'thaveanextensionandallfiles dohaveanextension,youcouldfindallfoldersinthemaindirectoryas follows: e%=FSFIRST("\*",&X10000) !ande%=FSNEXT()fornextfolders Ifyoucan'tusethissimplemethod,you'llhavetocheckaftereach successfulFSFIRST/FSNEXTifit'safolderorafile: IFBTST(BYTE{dta.adr%+21},4) (...) !yes,it'safolder ENDIF Usetheattribute-byte0(i.e.nobitsset)tofindordinaryfilesonly. Useattribute-byte&X1000tofindthedisk-name: dta.adr%=FGETDTA() e%=FSFIRST("\*.*",&X1000) !findsdisk-nameonly,ênotÇfiles disk.name$=CHAR{dta.adr%+30} YoucanreadtheattributesofafileorfolderwithGEMDOS67(Fattrib): attr%=GEMDOS(67,L:V:filename$,0,0) Ifthefile(orfolder)isnotfound,attr%is-33(or-34),otherwise attr%containstheattributesintheusualformat.Youcanevenchangethe attributesoffileswith: r%=GEMDOS(67,L:V:filename$,1,attribute%) It'snotpossibletochangetheattributesoffoldersorthedisk-name withGEMDOS67.Onewaytodothatistochangethedirectory-sectorwith theaidofBIOS4(Rwabs).Ifyoureallyfeeltheurgetoexperiment,you shouldrealizethatonetinymistakecouldruinthedisk. üEXISTÇ YoucanuseEXISTtotestifafolderexists,butonlyifthefolder containsatleastonefile: IFEXIST("\FOLDER\*.*") (...) !folderfound ELSE (...) !foldernotfoundêorÇemptyfolder ENDIF  üLOFÇ ThelengthofafileiseasilydeterminedwithLOF: OPEN"I",#1,file$ length%=LOF(#1) CLOSE#1 Todeterminethenumberofrecordsinarandomfileyoucoulddividethe file-lengthbythetotalFIELD-length. üTOUCHÇ UsethismethodwithTOUCH: OPEN"U",#1,file$ TOUCH#1 CLOSE#1 üNAMEÇ WiththeoldTOSyoucanonlychangethenameoffiles,ênotÇoffolders. Evenfromthedesktopyoucan'tchangethenameofafolder,sochooseit carefully. üKILLÇ KILLingafiledoesnoteraseitfromthedisk.Thefirstbyteofthe filenameischangedto&HE5.Unfortunatelyyoucan'trestoreakilledfile bysimplychangingthisbytewithadisk-editor.Theoperatingsystemwill beabletofindthefirstclusteroftherestoredfile,becausethefirst FAT-pointerislocatedinthedirectory.Thenextclusterscanonlybe foundthroughtheFAT(FileAllocationTable),butafterKILLallpointers tothisfileareirreversiblyerased.Ifyouhavenotkilledanyfileon thediskbeforeyourfatalmistake,youareextremelyluckyandwillfind allclustershavebeenstoredconsecutively.Butaftersomekillingand savingonthedisk,thefilecouldbedispersedovertheentiredisk.Some programsareabletohelpyou,butyouwillhavetorecognizeclustersas belongingtothekilledfile.That'seasywithASCII-files,butalmost impossiblewithotherfiles.So,don'tKILLunlessyouhaveto. üFileCopyÇ Youcancopyafilesource$todest$(usecompletepathnames!)with: PROCEDURE file.copy(source$,dest$) LOCAL block% OPEN "I",#90,source$ OPEN "O",#91,dest$ block%=LOF(#90) WHILE block%>32000 PRINT #91,INPUT$(32000,#90); SUB block%,32000 WEND PRINT #91,INPUT$(block%,#90); CLOSE #90 CLOSE #91 RETURN Donotcopyafile"toitself"onaharddisk.Thankstoyetanotherbugin TOS,thisactioncouldcompletelywipeouttheharddisk.Orperhapsthis shouldbecalledafeatureofTOS,puttheretopunishthecrazyuserwho triestocopyafiletoitself. ü DiskFormatÇ Adiskcontains80concentrictracks(numbered0-79)ormore.Sometimes theexpression"cylinder"isusedinsteadof"track".Eachtrackis dividedinto9,10oreven11sectors.Onesectorcancontain512data- bytes.InordertobecompatiblewithMS-DOS,TOSformatsadiskwith80 tracksand9sectors/track.Actuallyit'seasytofit10sectorsinone track.Withalittlemoreeffortyoucancreateroomfor11sectors,but somedrivesrunslightlytoofastandarenotabletoreadthe11th sector! Withadisk-editoryoucanexaminethe512data-bytesofasector,but youcan'texaminethesector-layoutwithoutaccessingtheFloppyDisk Controller(FDC)directly.Inthatcaseyouwouldfindthefollowing layoutforeachsector: data-separator(GAP) -15bytes ID-Addressmark -1byte sector-header -4bytes(track,side,sector,size) CRCofsectorheader -2bytes dataseparator -37bytes Data-AddressMark -1byte databytes -512bytes CRCofdatabytes -2bytes dataseparator -40bytes ThedataseparatorbytesaretheretosynchronizetheFDCproperly.The FDCrecognizesthesector-headerbytheprecedingID-Addressmark.The sector-headeritselfcontainsinformationaboutthecurrenttrack,side andsectorandalsoaboutthesizeofthedata-field(usually512bytes). TheFDCchecksboththesector-headerandthedata-fieldforcorrupted bytesbycomparingacomputed"checksum"withthestoredCRC-value.The operatingsystemcannotread/writeonebytefrom/toasector,only Çcompletesectorsarereadorwritten.GFA-Basictakescareofallthe dirtywork. Firstsomebadnews.ACRC-errorisnotalwaysrecognizedbytheROMof 520ST'sand1040ST's(buginXBIOS8,Floprd).Ifyourpalmsarenow gettingsweatty,youcouldcheckyourmostpreciousdiskswithXBIOS19 (Flopver).Thisfunctionchecksfor'lostdata,RNF-orCRC-errors'. Createabufferof1024bytesandcallXBIOS19.Asector(512bytes)is loadedfromthediskindriveAorB(0or1)intothesecondpartofthe bufferandchecked.Ifabadsectorisfound,thesector-numberisstored asawordinthefirstpartofthebuffer.Aftercheckingallsectorsin onetrackyouhavetoexaminetheword-listinthebuffer.Hopeyouwill findonly&H0000there.Ileavethewritingofthisprogramasanexercise tothereader.NeverthoughtIwouldusethatphrasemyself.Allright, here'ssomethingtogetstarted: buffer$=STRING$(1024,0) adr%=V:buffer$ r%=XBIOS(19,L:adr%,L:0,drive,1,track,side,9) !if9sectors/track Youshouldnowbeabletofindoutifthetrackonthisside(0or1)is OK.Goodluck. YoucanuseBIOS7(Getbpb)toexaminethedisk-formatintheso-called BIOS-Parameter-Block(BPB)ofthedisk: bpb.adr%=BIOS(7,drive) !addressofBPB,or0(=error) In9wordsyou'llfindthefollowinginformationintheBPB: êoffsetÇ 0 -bytes/sector(usually512) 2 -sectors/cluster(usually2) 4 -bytes/cluster 6 -numberofdirectory-sectors 8 -lengthofFAT 10 -firstsectorofsecondFAT 12 -firstdata-sector 14 -totalclusters 16 -flag(notused) UseGEMDOS54(Dfree)tofindouthowmanyfreeclustersareavailable,or simplyuseDFREEifyouwanttoknowhowmanyfreebytesareavailableon adrive.Duetoabug,GEMDOSmissesthelasttwoclustersonadisk.You can'twritetotheseclusters(2048bytesdownthedrain...),butyoucan readtheseclustersiftheydocontaindata.Thatwouldbeamiracle,or anMS-DOSdisk. You'llprobablyuseXBIOS10(Flopfmt)toformatadiskfromGFA-Basic.If youdo,use&H0000asthevirgin-valueforthefirst18sectors,andthen &HE5E5foralldata-sectors.Youcanuseeither9or10sectors/track,not 11.Ifyouuse10sectors/track,youshouldfillthefirsttwotrackswith &H0000andfillsectors19and20with&HE5E5afterwards(readthe paragraph'Sectors').Idon'trecommendmorethan80tracks,certainlynot morethan82tracks.IfXBIOS10returnsavalueotherthan0,you'llfind alistofbadsectorsinthebufferyouused(terminatedwith&H00).If oneofthefirst18sectorsisbad,youcanthrowthediskaway. ÇUsingXBIOS10,theinterleave-factorshouldbe1.Thismeansthesectors onatrackarenumberedconsecutively:1,2,3,4,etc.Idon'tunderstand whysomeprogrammersuseanothervalueandcallit'FastFormat'.TheFDC needsmoretimetoreadacompletetrackiftheinterleave-factorisnot 1.Perhapstheytrytocreatetheso-calledTwisted(orSkewed)format. TOSlosestimeiftheheadmovestothenexttrack.BecausetheSeekwith Verifyflagisset,theFDCfirstverifiesthetrack-numberandthenreads thesector-number.Whilecheckingthetrack-number,sector1waspassing, sowehavetowaitforonecompletespinofthedisk(200ms,yawn)until sector1canberead.OnesolutionistocleartheSeekwithVerifyflag, butthatcouldleadtonastyproblemsiftheheadstillrattlesslightly atthetimesector1isread.ThebestsolutionistheTwistedformat (adoptedbyAtarifromtheMegaSTonwards).Forasingle-sideddiskwith 9sectorsononetrackthismeans: track0:sector1,2,3,4,5,6,7,8,9 track1:sector8,9,1,2,3,4,5,6,7 track2:sector6,7,8,9,1,2,3,4,5 etc. Now,sector1isencounteredalmostimmediatelyafterthetrack-numberis verified.A1-sectoroffsetisnotpossible,buta2-sectoroffsetis enoughtosettletherattlinghead.Itisimpossibletoreaddatafaster fromadisk!ButI'mafraidyoucan'tformataTwisteddiskwithXBIOS10 ifyouhaveanoldTOS.Youhavetouseaspecialformat-program. Ifyouformatadiskfromthedesktop,badclustersareflaggedwitha specialvalueintheFAT.However,ifTOS1.4encountersabadsector, somethinggoeswrongandtheFATiscorrupted.Onemorereasontoquit smoking,becausesmoke-particlesdefinitelyconstituteaserioushazardto thehealthofyourdisks. YoucanuseXBIOS18(Protobt)tocreateabootsectorontheformatted disk.Don'tworryaboutthemedia-byte(disk-type),becauseTOSdoesn't useit.Douse&H1000000togeneratearandomserialnumber,becauseitis êveryÇimportantthatdifferentdiskshavedifferentserialnumbers!Write thebootsectortothediskwithXBIOS9(Flopwr),notwithBIOS4(Rwabs): r%=XBIOS(9,L:buffer%,L:0,drive%,1,0,0,1) Whyaredifferentserialnumberssoimportant?IfTOSsuspectsadisk- swap,theserialnumberisreadfromthedisk.Adisk-swapcanonlybe recognizedifthenumberonthenewdiskisdifferentfromtheoldnumber. Ifthenewdiskcontainsthesameserialnumber,TOSusestheFATofthe previousdisk.Writingtoaswappeddiskwillprobablyzapit,ifyou followme.Disk-copierscopyeverything,includingserialnumbers.Be careful! AlthoughitispossibletoformatadiskfromGFA-Basic,Idon'trecommend it(nowhetellsus...).Myfavouriteformatis: 80tracks 10sectors/track Twistedformat IuseTWISTER.PRG(notPublicDomain,asfarasIknow),butyoucoulduse aPublicDomainprogramlikeDCOPY(actuallyShareware).TheDesktopcan't copyaTwisteddisk,butfile-copyisalwayspossible.DCOPYcopiesany format,includingTwistedformat. üFileAllocationTable(FAT) Ç Thefirstsectoronadiskistheboot-sector.Thenextfivesectorsare reservedfortheFAT.AndthenextfiveforacopyoftheFAT(actually it'stheotherwayaround).Finally,themain(orroot)directoryoccupies thenext7sectors(32bytesforeachslot).Thismeansthatthefirst18 sectors(No.0-17)arereservedfortheoperatingsystem.Allother sectorsareavailableforstoringfiles. Thestorage-unitforfilesisacluster.Aclusterconsistsoftwo consecutivesectors(1024bytes).Afilethatcontainsonly1bytewill thereforestilloccupy1024bytes(1K)onthedisk.Whenafileissaved, theoperatingsystemlooksforthefirstemptycluster,thenthenext, etc.InformationaboutavailableclustersisstoredintheFATasa collectionofpointers.Duetoinefficientprogramming,thesearchfor freeclusterstakesalongtime.TryDFREEonaharddiskandyou'llagree. InstallaprogramlikeFATSPEED.PRG(PublicDomain,byUlrichKuebler)to speedthisup! ThefirstthreebytesoftheFATarenotusedbyTOS,butarethereto enableMS-DOStoreadanST-formatteddisk.TOSwrites&HF7FFFF,wherethe firstbyte(&HF7)issupposedtobethemedia-byte.UnfortunatelyMS-DOS doesn'tunderstandthisandrefusestoreadthedirectoryproperly.I'm notquitesurewhy,butchangingthefirstthreebytesto&H000000seems towork.Youcouldtry&HF8FFFF(80tracks,9sectors/track,singlesided disk)or&HF9FFFF(doublesideddisk)instead.Oryoucouldusethemedia- byteatoffset21fromthebootsector.TomakeyourMS-DOSfriends completelyhappy,youshouldchangethefirstthreebytesofthebootsec⑨ torto:&HEB3890.Sometimes(DOS4.0?)youhavetochangethenextthree bytesaswell:&H49424D(that'sIBMinASCII;pleasewatchyourlanguage). Betterstill,letthemusetheirowndiskeditorontheirMS-DOScomputer (e.g.NortonUtilities).Whyshouldyoudoallthework?Bytheway,your STshouldbeabletouseanMS-DOSdiskwithoutanymodifications. EachFAT-pointerconsistsofoneandahalvebyte(3nibbles,i.e.12 bits).Inhexadecimalnotationthismeansthreedigitsforonepointer. Thefirstpointer(No.0)pointstoclusterNo.0,thesecondtoNo.1, etc..Becausethefirsttwopointersdon'tcount,youhavetosubtract twotofindtheactualcluster(pointer2pointstoclusterNo.0,etc.). ThefirstclusterstartsatsectorNo.18(remember,sectors0-17are reservedforbookkeeping),soyoucouldfindthefirstsectorofacluster with: (pointer-2)*2+18 Thesecondsectorofthisclusterisofcoursethenextone. ÇTOSreadsthepointersinapeculiar(MS-DOS)way.SupposetheFAT-sector startswith: F7FFFF034000FF0F00 Withoutfurtherexplanation,thistranslatesto: FAT-pointer0and1areignored FAT-pointer2=&H003(nextclusteronsector20+21) FAT-pointer3=&H004(nextclusteronsector22+23) FAT-pointer4=&HFFF(lastclusterofthisfile) FAT-pointer5=&H000(freecluster) Inordertounderstandthis,youhavetoconsultthefollowingtable: &H000 :clusterstillavailable &HFF1-&HFF7:badcluster,neveravailable &HFF8-&HFFF:lastclusterofthisfile(EndOfFile) &H002-&HFF0:pointertonextcluster AssumingtheFAT-pointer&H002atoffset26inthedirectory(you'llfind &H0200withadiskeditor,that'sIntelformatwithêlowÇbytefirstagain), youshouldbeabletofigureoutthatthisfilewillbefoundinsectors 18through23.Sectors24/25areempty,sothisclusterisavailablefora newfile.Anyquestions?Theonebigadvantageofallthisiscompatibi⑨ litywithMS-DOSdisks.WithTOS1.4yourST-diskscanbemadecompletely compatible,soyoudon'tevenhavetochangeafewbytes. Right,youhavejustreadtheFatman-book.Themoviewillbereleased shortly,butyoucanNOWbuythosefabulousFatman-shirtsandfantastic Fatman-buttons.CallAtariforfurtherdetails. üSectorsÇ Therearetwodifferentmethodstoassignanumbertoasector.Thefirst oneistonumberthe"physical"sectorsineachtrackfrom1to9 (assuming9sectors/track).Thiswayyoucouldsaythebootsectoris sector1ontrack0(onside0ifthediskisdoublesided).ButGEMDOS doesn'tcareabouttracksorsides,itcounts"logical"sectorsfrom0to 719(80tracks,9sectors/track,onesideddisk)orfrom0to1439(double sideddisk).AccordingtoGEMDOS,thebootsectorisonsector0.Andona doublesideddisk,physicalsector1ontrack0ofside1(theotherside) wouldbesector9. WithBIOS4(Rwabs)youcanread(andwrite)completeêlogicalÇsectors: buffer$=SPACE$(512) !512bytesfor1sector buffer%=V:buffer$ !addressofbuffer r%=BIOS(4,0,L:buffer%,1,sector%,drive%) !loadthesucker YouwouldloadthebootsectorfromthediskindriveAwith: r%=BIOS(4,0,L:buffer%,1,0,0) YoucanuseBIOS4notonlywithfloppydisks,butalsowithaharddisk oraRAM-disk.Afterloadingasector,youcanreadonebytewith: b|=BYTE{buffer%+n}  !nfrom0to511 Youcanreadawordwith: w=WORD{buffer%+n} ButonlyifthewordstartsatanêevenÇaddress.Otherwiseyouhavetouse: w=BYTE{buffer%+n+1}+256*BYTE{buffer%+n} ÇIfnecessary,youcanspeedthisupbyusingthespecialintegercommands foradditionandmultiplication.HowaboutthisPolishmonster: DEFFN word(adr%)=ADD(BYTE{SUCC(adr%)},MUL(256,BYTE{adr%})) Thenyouwoulduse: w=@word(ADD(buffer%,n)) IfyouuseBIOS4towriteasectorafterformattingadisk,youshould use'3'asaflag(not'1'): r%=BIOS(4,3,L:buffer%,1,sector%,drive%) YoucanalsoreadandwriteêphysicalÇsectorswithXBIOS8(Floprd)and XBIOS9(Flopwr).Withthesecommandsyoucouldevenread/writeall sectorsononetrack.Thisistheonlywaytoreadatrack,because readingacompletetrackisimpossibleduetoabugintheFDC. Ifyouswapadiskafterloading/writingasectoryoushouldbecareful. TestingwithBIOS9(Mediach)youcouldêmissÇthedisk-swap.Thiscouldbe fatal,becauseTOSusestheFAToftheotherdisk!Ithinkyoucoulduse BIOS7(Getbpb)inmostcases,butusetheProcedureForce.mediachifin doubt: PROCEDUREforce.mediach LOCALx$,old.vector%,a% x$=SPACE$(12)  old.vector%=LPEEK(&H47E)  a%=V:x$ DPOKEa%,&H2B7C LPOKEa%+2,old.vector% DPOKEa%+6,&H47E  DPOKEa%+8,&H7002 DPOKEa%+10,&H4E75 SLPOKE&H47E,a% ~DFREE(0) !currentdrive RETURN Tobemoreprecise,BIOS7can'tbeusedinthefollowingsituation: -TOSreadsasector -youswapdisks -youuseBIOS7inyourprogram -TOSreadsasector NowTOSwillassumetherehasbeennodisk-swap,becausetherehasbeenno disk-swapafterthelastBIOS7call!YoudefinitelyneedtheProcedure Force.mediachinthiscase. Bythetrack,TOSalsoignoresdisk-swapsduringascreendump(HARDCOPY), orwhileusingDMA(harddisk,laserprinter).TOSdetectsadisk-swapby monitoringthewrite-protectstate.Toseethis,youshouldturnall lightsoffandthenwatchthedrive-lightclosely.Closer.Youcanturn thelightsonagain.Ifthedriveisempty,TOSgetsawrite-protect signalandassumestheusermighthaveswappeddisks.BIOS9shouldreturn '1'atthispoint.TOSchecksifyoureallydidswapdisksbyreadingthe serialnumberfromthebootsectorandcomparingitwiththecurrent number.Onlyifthesenumbersaredifferent,adisk-swapisrecognizedby TOS(BIOS9shouldreturn'2'now).YouprobablydeducedthatTOSwill readthebootsectoralsoifyouuseawrite-protecteddisk.Continuously readingthebootsectorisawasteoftime,soTOSwaits1.5secondsbefore Çlookingagain.Neverswapdiskswithin1.5secondsafteraread/write- operation.Thedrivekeepsspinningfor2seconds,soyoucan'tgowrong ifyouwaituntilthedrive-lightisoffbeforeswappingdisks. üBootsectorÇ Inthefollowingtableyou'llfindthelay-outofabootsector.Allwords areinIntel-format,exceptCHKSUM. êoffsetÇ êlengthÇ ênameÇ 0 2 &H6038=branchtobootroutine 2  6 FILLER fill-bytes 8 3 SERIAL serial-numberofdisk 11 2 BPS bytes/sector(512) 13 1 SPC sectors/cluster(2) 14  2 RES reservedsectors(1,Bootsector) 16 1 NFATS numberofFAT's(2) 17 2 NDIRS max.entriesinmaindirectory 19 2 NSECTS totalsectors 21 1 MEDIA media-byte(notusedbyTOS) 22 2 SPF sectors/FAT(5) 24 2 SPT sectors/track 26 2 NSIDES sides(1or2;nojokethistime) 28 2 NHID hiddensectors(ignoredbyTOS) 30 2 EXECFLAG startofbootcode:flag 32 2 LDMODE 0=loadFNAME;<>0=loadsectors 34 2 SSECT firstsector(LDMODE<>0) 36 2 SECTCNT numberofsectors 38 4 LDADDR loadatthisRAM-address 42 4 FATBUF addressofFAT-buffer 46 11 FNAME filename(nnnnnnnneee)(LDMODE=0) 57 1 DUMMY fill-byte 58 boot-routine(couldbeaboot-virus) 510 2 CHKSUM TOSdeterminesifthebootsectorisexecutablebyaddingallbytes.If thissum(AND&HFFFF)equals&H1234,thebootsectorisexecutable.Ifyou useGFA-BasicthisprobablymeansyouhaveanancientSTwithTOSinRAM, oraboot-virus.AnormalGFA-diskhasonly&H00-or&HE5-bytesfromthe offset58. üBLOADÇ BLOADneedsanaddress,unlessyouhaveusedBSAVEinthesameprogram before.InthatcasetheBSAVE-addressisusedautomaticallybyBLOADif youdon'tspecifyanewaddress. ÇBLOAD(BSAVE)iseasiertousethanBGET(BPUT),becauseyoudon'thaveto openthefile.ButwithBLOADyoucanonlyloadtheentirefile,while BGETallowsyoutoloadanypartofthefile. üINPandOUTÇ BothINPandOUTcanalsobeusedwith2-byteand4-byteintegers: a|=INP(#n) a&=INP&(#n) a%=INP%(#n) OUT#n,a| OUT&#n,a& OUT%#n,a% üINPUTandLINEINPUTÇ BecauseGFAnowusesa4K-bufferforeachopenedfile(version3.07), readingdatafromafilewith(LINE)INPUTgoesmuchfaster. üSTOREandRECALLÇ Forveryfastloadingandsavingofstring-arrays,youshoulduseRECALL andSTORE.Youcanalsostore(orrecall)apartofanarrayasfollows: STORE#1,txt$(),10 !storeelements0through9 STORE#1,txt$(),5TO10 !storeelements5through10 Thecorrectsyntaxis: STORE#i,x$()[,n[TOm]] RECALL#i,x$(),n[TOm],x% (usen=-1forcompletearray) Ofcourseyouhavetoopenthefilefirst. IfyouSTOREatext-array,GFAputs&H0D0A(CHR$(13);CHR$(10))aftereach element.Thisisthesameformatasusedby1stWordPlus(WPModeoff, i.e.ASCII-mode),Tempus,etc. Ifyou'regoingtoshowmorethanafewtext-lines,youcouldenterthe textasDATA-lines,e.g.withtheProceduresInitio.text.arrayand Initio.text.array.low(forLowresolution): PROCEDURE initio.text.array ' *** global : TEXT$() LOCAL lines,line$,n lines=0 RESTORE txt.data READ line$ REPEAT INC lines READ line$ UNTIL line$="***" Ç ERASE text$() DIM text$(lines) RESTORE txt.data FOR n=1 TO lines READ text$ text$(n)=SPACE$(5)+text$ ! left margin of 5 spaces !! NEXT n txt.data: DATAtext DATA *** RETURN Ifyouaregoingtoshowmoretext,Isuggestyouuse1stWordPlus,or anyotherwordprocessorortext-editorthatcansaveyourtextasan ASCII-file.With1stWordPlus,IuseaRulerlengthof70andthe followingPageLayoutForm: Paperlength 66 TOFmargin 19 Headmargin 4 Footmargin 4 BOFmargin 19 Lines/page 20 EnterthetextandsaveasanASCII-file(turnWPModeoffbeforesaving). InyourGFA-Basicprogramyouwouldfirstloadthetextinastring-array: DIMtext$(lines) OPEN"I",#1,file$ RECALL#1,text$(),-1,lines%!lines%≤lines+1 CLOSE#1 ThenyoucouldusetheProcedureShow.text.page(HighorMediumresolu⑨ tion)toshowthetextwith20lines/screen.TheProcedureusesaleftand rightmarginof5characters,sothat'swhyyouhavetouse70charac⑨ ters/lineinyourwordprocessor.Ifthetext-arrayisfull,youwon'tget anerrorifthefilecontainsmoretext-lines! Youcouldusea2-dimensionalstring-arraytostorefirstandlastnames: name$(i,0)=first_name$ name$(i,1)=last_name$ Again,STOREandRECALLareveryfast.Butitisnownecessarytouse exactlythesamedimensionswithRECALLthatyouusedwithSTORE.Ifthe dimensionsdon'tmatch,thearraywillbescrambledafterRECALL. üFILESELECTÇ Don'tusetheunderscore'_'inthepath-lineoftheFileselector,because abugintheoldTOSwillthencauseafewbombs.OwnersofaMegaSTor TOS-version1.4canuseasmanyunderscoresastheylike. ChangingdrivesintheFileselector(oldTOS)isnoteasy.Clickonthe path-lineandpress<Esc>tocleartheline.Enterthedrive,e.g.'D:\', andclickêonÇthebarunderthepath-lineinordertoreadthenew directory.Alsoclickonthisbarafterchangingdisks(inthiscaseyou wouldpress<Esc>onthedesktop).SelectingdriveAiseasier:justclear thepath-lineandclickonthebar.TheTOS-codethattakescareofall Çthisworkisalsoknownasthebartender. Ifyouhavechangedtheextensioninthepath-line,youshouldclickêjust belowÇthebar.IfyouclickêonÇthebar,thepath-lineisoverwrittenwith '*.*'!Thatsamebartenderstrikesagain. ThecorrectsyntaxforcallingtheFileselectoris: FILESELECT[#title$,]path$,default$,file$ ThetitleisonlyusedinTOS-version1.4andignoredinolderTOS- versions.Thedefault$usuallyisthenull-string(""),butdon'tusethe null-stringforpath$ortheFileselectorwillfreeze.Use"\*.*"aspath$ forallfilesinthemaindirectory.Dousethebackslashinthepathname (e.g."A:\*.*").DuetoabuginGEM,thewrongdriveissometimesusedif youforgetthebackslash("A:*.*").Iftheuserhasselectedafile,file$ willcontainthepathandfilename.Thefile$willbethenull-stringif theuserselected<Cancel>.Athirdpossibilityiseasilyoverlooked:the usercouldhaveselected<OK>withoutchoosingafile.Inthatcasefile$ containsthecurrentpath,endingwithabackslash. Donotdespairifyouneedatitle,butdon'thaveTOS1.4.Trythe ProcedureFileselect(HighorMediumresolution)orFileselect.low: PROCEDURE fileselect(path$,default$,txt$,left$,right$,VAR file$) ' *** print optional title (light text) to left and right LOCAL screen$,y.fac SGET screen$ CLS IF high.res! y.fac=1 ELSE y.fac=2 ENDIF DEFTEXT black,2,900,32 TEXT 100,350/y.fac,300/y.fac,left$ DEFTEXT ,,2700 TEXT 540,50/y.fac,300/y.fac,right$ DEFTEXT ,0,0,13 PRINT AT(1,3);@center$(txt$) GRAPHMODE 3 DEFFILL black,1 BOUNDARY 0 IF high.res! BOX 157,25,482,54 PLOT 157,25 PBOX 159,27,480,52 ELSE BOX 157,12,482,27 PLOT 157,12 PBOX 160,14,479,24 ENDIF BOUNDARY 1 GRAPHMODE 1 FILESELECT path$,default$,file$ SPUT screen$ RETURN ÇAsaprogrammer,youshouldtakeintoaccountthepossibilitythatauser mightstartyourprogramfromdriveA,aharddiskoraRAM-disk.Iusethe StandardGlobaldefault.path$torememberwheretheprogramwasstarted. Iftheuserchangesthe(default)pathintheFileselector,youshould notethechangeandusethenewpathiftheFileselectoriscalledagain. UsetheProcedureParse.filenameforthispurpose: PROCEDURE parse.filename(parse.name$,VAR drive$,path$,file$,ext$) LOCAL pos,first,last,last!,search,parse.file$ ' parse.name$=UPPER$(parse.name$) IF MID$(parse.name$,2,1)=":" drive$=LEFT$(parse.name$,1) ELSE drive$=CHR$(65+GEMDOS(&H19)) ! current drive ENDIF ' pos=1 last!=FALSE last=0 first=INSTR(1,parse.name$,"\") REPEAT search=INSTR(pos,parse.name$,"\") IF search>0 pos=search+1 last=search ELSE last!=TRUE ENDIF UNTIL last! IF last>0 ! backslash discovered path$=MID$(parse.name$,first,last-first+1) parse.file$=MID$(parse.name$,last+1) ELSE ! no '\' path$="" pos=INSTR(1,parse.name$,":") IF pos>0 parse.file$=MID$(parse.name$,pos+1) ELSE parse.file$=parse.name$ ENDIF ENDIF pos=INSTR(parse.file$,".") IF pos>0 ! name with extension ext$=MID$(parse.file$,pos+1) file$=LEFT$(parse.file$,pos-1) ELSE ! name without extension ext$="" file$=parse.file$ ENDIF RETURN IfyouhaveajoystickwithAuto-Fireon,youshouldswitchitoff.The Fileselectordoesn'tlikeAuto-Fire.NeitherdoI. ÇTheFileselectorwillwarnyouwithamodest'ping'ifitcountsmorethan 100files/folders.Itwillshowonlytheêfirst100Çfiles/folders.Ithink 45filesinonefolderisreallythelimitforimpatientuserslike myself.Morethan100isacrimethatshouldbepunishedwithmorethana 'ping'.ThemaindirectoryofdriveAcan'tcontainmorethan112 files/folders,becausethe7directory-sectorscontain11232-byteslots. Everytimeyouopenafolder(intheFileselector,orotherwise),TOS storesinformationaboutthefolderinatable.Afteropening/accessing40 folders,TOSwilldeleteclusters,cross-linkclusters,anddoothernasty things.Yourdiskcouldbecompletelydestroyed,thankstothisbug.Atari enlargedthebufferinTOS1.2andfixedthebuginTOS1.4.Atarialso distributestheprogramFOLDRxxx.PRGtoextendthe40-folderlimitwith 100(FOLDR100.PRG)ormore.BecarefulwithSHOWINFO,it'seasytoexceed the40-folderlimit!Youcouldrecognizeadisasterbyoneofthe followingsymptoms: -unexpected'0bytesin0items'messageindirectory -folder-namestrashed(usuallylotsofGreekletters) -ShowInfocrashesorshowsweirdinformation Don'tbeafraidofanewvirus.It'sonlyaTOS-bug.Immediatelyreset yourST,trytosalvageasmanyfilesaspossibleandreformatthedisk. Ifallfilesarelost,youwillhavetouseyourback-upfiles.Ifyou don'thaveback-upfiles,youhavenothingleftbutmysympathy. üë12.MIDI Ç üINPMID$Ç WiththecommandINPMID$theinternalMidi-bufferisreadandatthesame timecleared.YoucanfindthebufferwithXBIOS14(Iorec): adr%=LPEEK(XBIOS(14,2)) Thedefaultsizeofthisbufferisonly128bytes,butyoucanusethe ProcedureChange.midi.buffertochangethesizeofthebuffer: PROCEDURE change.midi.buffer(size%) LOCAL ptr% ptr%=XBIOS(14,2) ERASE buffer|() DIM buffer|(size%-1) LPOKE ptr%,VARPTR(buffer|(0)) ! start-address ofnew buffer DPOKE ptr%+4,size% ! size DPOKE ptr%+6,0 ! buffer-head DPOKE ptr%+8,0 ! buffer-tail DPOKE ptr%+10,0 ! low mark (not used) DPOKE ptr%+12,size%-1 ! high mark (not used) RETURN BecausehandshakeisimpossiblewithMidi,youneedalargebufferif Midi-bytesarecominginfast. üINPÇ IfyouuseINP(3)toreadMidi-bytes,youshouldfirstcheckwithINP?(3) iftheMidi-buffercontainsdata.IfyouuseINP(3)andnobytesare available,yourSTwillfreeze.Untilyouresetthecomputer. üMidi-commandsÇ StudytheProceduresinthefileMIDI.LSTtoseehowyoucanuseMidi- commandsinGFA-Basic.WiththeProceduresRecord.midiandPlay.midiyou couldwriteasimpleMidi-recorder.AndtheProcedureMidi.monitorcanbe usedtoexamineincomingMidi-messages. PROCEDURE record.midi(VAR midi.byte|(),midi.time%()) ' *** uses Procedure All.midi.off ' *** global : LAST.MIDI.BYTE% LOCAL last%,buffer$,i%,t%,time%,byte|,delay%,j%,m$,k ARRAYFILL midi.byte|(),0 ARRAYFILL midi.time%(),0 last%=DIM?(midi.byte|())-1 m$=STR$(last%)+" bytes available ;| |stop recording|" m$=m$+"by pressing space" ALERT 3,m$,1,"RECORD",k REPEAT UNTIL INKEY$="" buffer$=INPMID$ ! clear MIDI-buffer i%=1 t%=TIMER Ç REPEAT IF INP?(3) byte|=INP(3) IF byte|<>254 time%=SUB(TIMER,t%) midi.byte|(i%)=byte| midi.time%(i%)=time% INC i%  ENDIF ENDIF UNTIL i%=last% OR INKEY$=" " last.midi.byte%=i%-1 @all.midi.off delay%=midi.time%(1) ! subtract time for first note FOR j%=1 TO i% SUB midi.time%(j%),delay% NEXT j% m$="|"+STR$(i%)+" bytes recorded" ALERT 3,m$,1," OK ",k RETURN ' PROCEDURE play.midi(VAR midi.byte|(),midi.time%()) ' *** uses Procedure All.midi.off LOCAL m$,k,i%,t%,time% m$="record of "+STR$(INT(midi.time%(last.midi.byte%)/200))+ m$=m$+" seconds| |(stop by pressing space)" ALERT 3,m$,1,"PLAY",k REPEAT UNTIL INKEY$="" i%=1 t%=TIMER REPEAT time%=SUB(TIMER,t%) IF midi.time%(i%)<=time% OUT 3,midi.byte|(i%) INC i% ENDIF UNTIL i%=last.midi.byte% OR INKEY$=" " @all.midi.off RETURN ' PROCEDURE midi.monitor LOCAL m$,k,byte|,byte$,hex$,bin$,buffer$,key$ byte$=SPACE$(3) hex$=SPACE$(2) bin$=SPACE$(8) m$="all incoming bytes|(except 254) are|printed on screen ;|" m$=m$+"stop by pressing space" ALERT 1,m$,1,"START",k m$="press|<Return>|for CLS" ALERT 1,m$,1," OK ",k REPEAT UNTIL INKEY$="" Ç buffer$=INPMID$ ! clear MIDI-buffer CLS PRINT TAB(10);"dec";TAB(20);"hex";TAB(30);"binary" REPEAT REPEAT key$=INKEY$ IF INP?(3) byte|=INP(3) IF byte|<>254 IF TIMER-t%>200 PRINT ENDIF t%=TIMER RSET byte$=STR$(byte|) RSET hex$=HEX$(byte|) RSET bin$=BIN$(byte|) PRINT TAB(10);byte$;TAB(20);hex$;TAB(30);bin$ ENDIF ENDIF UNTIL key$=" " OR key$=CHR$(13) IF key$=CHR$(13) CLS ENDIF UNTIL key$=" " @all.midi.off REPEAT UNTIL INKEY$="" PRINT " (press any key)" ~INP(2) RETURN üë13.MODEM Ç üINPAUX$ ÇWiththecommandINPAUX$theinternalRS232-bufferisreadandatthesame timecleared.Youcanfindtheaddressoftheinput-bufferwith: adr.in%=LPEEK(XBIOS(14,0)) Theoutput-buffercanbelocatedwith: adr.out%=LPEEK(XBIOS(14,0)+14) üINPÇ IfyouuseINP(1)toreadincomingbytes,youshouldalwayscheckwith INP?(1)iftheRS232-buffercontainsdata. üRsconf(XBIOS15)Ç WithXBIOS15(Rsconf)youcanchangetheRS232-parameters.Afew baudrates: 0-19200baud 1-9600baud 4-2400baud 7-1200baud 9-300baud 14-75baud Use-1forparametersyoudon'twanttochange.DuetoaTOS-bug,you can'tuse75baud,because'14'resultsin120baud.Also,theoldTOS (pre-Blitterage)can'thandlehardwarehandshakewithRTS/CTS-signals. Atarihasreleasedabug-fixthatshouldenableanyTOStouseRTS/CTS. Softwarehandshaking(XON/XOFF)functionsproperly.Thedefault afterpower-up isnohandshakeprotocol. üë14.MOUSE Ç üEditorÇ Sometimestheeditorseemstofreezewhilethecursorisblinkingrapidly. Justmovethemouseandtheeditorcomesaliveagain. üFileselector ÇSometimesthesameblinkingmouseappearsaftercallingtheFileselector oranAlert-box.I'vereadsomewherethiscouldbeduetothecombination ofaVDI-function(forthemouse)andanAES-function(forFileselectoror Alert-box).GFAtakescareofthefirstandGEMofthesecond,and sometimesthisseemstoresultinaconflict. üMOUSEÇ IfyourepeatedlycallaProcedureinwhichyoutestforamouse-click, youshouldincorporateashortpauseintheProcedure(e.g.PAUSE5). OtherwisetheProceduremightbecalledagainwhiletheuserisstill holdingthebuttondown.Youcouldalsowaituntiltheuserreleasesthe button: REPEAT UNTILMOUSEK=0 !waituntilbuttonisreleased Ifyoufinditdifficulttomovethemouseaccurately,youcoulduse <Shift><Alternate><arrow>tomovethemouse-cursoronepixelinthe desireddirection.Ifyoupress<Insert>aswell,youcan"drag"something accuratelyasiftheleftmouse-buttonwaspressed. Youcanfindthemaximalx-andy-coordinatesofthemousewith: x=DPEEK(&H9862) y=DPEEK(&H9864) Butthere'snoguarantyyouwillfindthecoordinatesthere.Experiment withXBIOS0foramorereliablemethod.Don'taskmehow. MOUSEreturnsnegativecoordinatesifthemouseistotheleftoforabove thecurrentwindow(ortheoriginthathasbeenselectedwithCLIP OFFSET). üSETMOUSEÇ Amouseclickcanbesimulatedwith: SETMOUSEmx,my,mk IfyoutrythiswithanAlert-buttonyouhavetomovethemouseafter- wards,orthebuttonwon'tbeselected.Idon'tknowwhy,soIcan'ttell ifthisisabug. üDEFMOUSEÇ YoucanuseoneofthemanyPublicDomainmouse-editorstodesignyourown mouse-mutant.Butit'salsoeasytocreateanewmouse-cursorwiththe ProcedureInitio.mouse1: PROCEDURE initio.mouse1 ' *** global : MOUSE1$ RESTORE pattern.mouse1 @make.mouse(mouse1$) pattern.mouse1: ' *** x,y,mode(0=normal;1=XOR),mask-colour,mouse-colour DATA 0,0,0,0,1 ' *** mask-pattern (1 = pixel on , 0 = pixel off) DATA 0000000000000000 DATA 0000000000000000 DATA 0000000000000000 DATA 0000000000000000 DATA 0000000000000000 DATA 0000000000000000 DATA 0000000000000000 DATA 0000000000000000 DATA 0000000000000000 DATA 0000000000000000 DATA 0000000000000000 DATA 0000000000000000 DATA 0000000000000000 DATA 0000000000000000 DATA 0000000000000000 DATA 0000000000000000 ' *** mouse-pattern DATA 0000000000000000 DATA 0000000000000000 DATA 0000000000000000 DATA 0000000000000000 DATA 0000000000000000 DATA 0000000000000000 DATA 0000000000000000 DATA 0000000000000000 DATA 0000000000000000 DATA 0000000000000000 DATA 0000000000000000 DATA 0000000000000000 DATA 0000000000000000 DATA 0000000000000000 DATA 0000000000000000 DATA 0000000000000000 RETURN ' Ç PROCEDURE make.mouse(VAR m$) LOCAL x,y,mode,msk.color,mouse.color,n,msk%,mouse%,msk.pat$ LOCAL mouse.pat$,msk$,mouse$,pat$ CLR msk.pat$,mouse.pat$,pat$ READ x,y,mode,msk.color,mouse.color FOR n=1 TO 16 READ msk$  msk%=VAL("&X"+msk$)  msk.pat$=msk.pat$+MKI$(msk%) NEXT n FOR n=1 TO 16 READ mouse$ LET mouse%=VAL("&X"+mouse$) LET mouse.pat$=mouse.pat$+MKI$(mouse%) NEXT n m$=MKI$(x)+MKI$(y)+MKI$(mode)+MKI$(color.index(msk.color)) m$=m$+MKI$(color.index(mouse.color))+msk.pat$+mouse.pat$ RETURN Themaskshouldbeanexactcopyofthemouse-patternifyouneeda transparantmouse.Leavethemaskempty(all'0')andthemousewill disappearbehindobjectsonthescreen.Fillthemaskwith'1'andthe 16x16mousewillalwaysremainvisible.Switchmask-andmouse-colourin thefirstDATA-linetocreatea"reverse"mouse.OruseanyVDIcolour- indexthatisavailableinthecurrentresolution. üë15.JOYSTICK Ç üSTRIGandSTICKÇ HereisanexampleoftheuseofSTRIGandSTICKifyourjoystickis connectedtoPort1(yourmouseisconnectedtoPort0): STICK1 !joystick-mode(yourmouseisnowdead) REPEAT IFSTRIG(1) joy=3 ELSE joy=STICK(1) ENDIF ONjoyGOSUBn,s,fire,w,nw,sw,dummy,e,ne,se PAUSE5 (...) UNTILcondition! STICK0 !backtomouse-mode YouneedeightProceduresfortheeightpossibledirections(seebelow) andoneProcedurefortheFire-button.Thevalue7('dummy')neveroccurs. Ifyoudon'ttouchthejoystick,thevalueof'joy'willbe0,andthis meansnoProcedurewillbecalled.Ashortpauseisadvisable,because GFA-Basicistoofast.  519 \|/ directions:  4-0-8 /|\ 6210 Ifyoudesperatelyneedanactivemousewhileusingthejoystick,you couldtrythefollowing"dirty"method: REPEAT IF MOUSEK=2 joy=3 ELSE joy=BYTE{&HE09} ! forTOS-version1.0!! ENDIF ON joy GOSUB n,s,fire,w,nw,sw,dummy,e,ne,se PAUSE 5 UNTILcondition! üë16.SOUND Ç üSOUNDÇüandWAVEÇ AfteraSOUND-command,thesoundsometimescontinuesinspiteofthe elapsedtime.IfthecommandisfollowedbyanotherSOUND-oraWAVE- command,thetimeishandledcorrectly.ThiscertainlysoundslikeaGFA- bug. Theeasiestwaytostopallsoundis: WAVE0,0 !turnallsoundoff Soundofacertainfrequencycanbeproducedwith: SOUNDch,vol,#ROUND(125000/freq%),pause AlthoughourSTisnotfamousforitsbrilliantsound,youcanproduce nicesound-effectswiththesimplecommandsSOUNDandWAVE.Checkoutthe ProceduresSiren.sound,Tideli.sound,Bounce1.soundandBounce2.soundto hearwhatImean. üDosound(XBIOS32)Ç XBIOS32(Dosound)canbeusedtoplaymusicinaspecialformat.I proposetousetheextension'X32'forsong-filesinthisformat.The operatingsystemtakescareofplayingthemusicduringinterrupts(every 1/50thsecond).TakealookattheProceduresPlay.songandStop.songto seehowyoucoulduseXBIOS32inyourprograms.Youcanevenplayasong continuouslywiththeProcedurePlay.cont.song.Temporarilystoppinga songispossiblewiththeProcedureInterrupt.song. IfyouuseXBIOS32toplaymusic,youareadvisedtoswitchthekey-click off.Otherwisethemusicwillstopassoonastheuserpressesakey. OnceIdiscoveredXBIOS32didnotworkduringtheinitialization(mainly thefillingofarrays)ofalargeprogram.Ihadconvertedtheprogram fromGFA-Basic2.0to3.0,butIdidnothavethepatiencetofindout whatcausedthisproblem. XBIOS32canalsobeusedforsound-effects.Ihavedevelopedthe ProcedureInitio.soundforbuildingsound-stringsfromafewDATA-lines. Iherebydeclarethisasthestandardmethodforcreatingsound-strings. After@do.sound(sound$)youcanhearthesound-effect.Inthefollowing examplethesound-stringbounce3$iscreated: PROCEDURE initio.sound ' *** commands in DATA-lines : ' *** REG = 14 parameters for registers 0-13 ' *** END = end of sound-string ' *** PAUSE = pause (followed by time in 1/50 seconds) ' *** VAR = decrease/increase tone : channel,start,+/-step, '***end-value Ç ' bounce3.sound: DATA REG,0,0,0,0,0,0,27,248,16,16,16,35,95,0 DATA VAR,3,255,-1,116 DATA PAUSE,255,END RESTORE bounce3.sound @sound.string(bounce3$) RETURN ' PROCEDURE sound.string(VAR s$) LOCAL n,snd$,snd,channel,begin,step,end s$="" DO READ snd$ snd$=UPPER$(snd$) EXIT IF snd$="END" IF snd$="REG" FOR n=0 TO 13 READ snd s$=s$+CHR$(n)+CHR$(snd) NEXT n ENDIF IF snd$="PAUSE" READ snd s$=s$+CHR$(130)+CHR$(snd) ENDIF IF snd$="VAR" READ channel,begin,step,end s$=s$+CHR$(128)+CHR$(begin)+CHR$(129)+CHR$(channel)+CHR$(step) s$=s$+CHR$(end) ENDIF LOOP s$=s$+CHR$(255)+CHR$(0) ! terminator RETURN ' PROCEDURE do.sound(sound$) VOID XBIOS(32,L:VARPTR(sound$)) RETURN üSamplesÇ FromGFA-Basicyoucansurprisetheuserwithasampledsound.Examinethe ProceduresSample,Load.sampleandPlay.sampletoseehow.You'llhaveto findsuitablesamplesfirst.Lookoutforsound-effectsandspeech- samples.Personally,IjustlovethefamousPerfect-sample. ü üSpeechÇ YourSTcantalktoyouwithalittlehelp(STSPEECH.TOS).MycurrentGFA- version(3.07)refusestocooperatewiththeProceduresInitio.speechand Talk,butIhaveincludedtheseanyway.Perhapsyoucandiscoverthebug. InearlierversionsbothProceduresdidwork.Aresetisnecessarybecause EXEC3isused. üSoundmachineÇ Youcanplaysongs,createdwithSoundmachine(TommySoftware),fromGFA- Basic.You'llneedtheProceduresInitio.soundmachineandSoundmachine, andasong-file.You'llprobablywonderifit'sreallyyourSTthat's playingthesong.SoundmachineIIisout,andlooksevenbetter.Inthis newversionyoucanchoosebetweenplayingsongswithsamples,orwithout samples(orsamplesforoneofthethreechannels).You'llneedthe ProcedureSm.initioorMsm.initioandseveralothers.Trytofindthe PublicDomaindemo-programsSAMSOUND.GFA,CHIPSND.GFAandSND_PLAY.GFA. Endofcommercial,continuewithtext. üë17.PROGRAMDECISIONS Ç üIF...ENDIFÇ Ifthevalueofacertainvariablemustfallintherangemin%-max%,you couldprogramthatasfollows: IFn%>max% n%=max% ENDIF IFn%<min% n%=min% ENDIF InthiscaseyoucouldalsouseMAXandMIN: n%=MAX(MIN(n%,max%),min%) Youprobablytestfortwoconditionsbyusing: IFcond1!ANDcond2! (...) !bothtrue ENDIF Butseparatetestingismuchfaster: IFcond1! IFcond2! (...) !bothtrue ENDIF ENDIF üSELECTÇ Multiple'ELSEIF'-constructionscanbereplacedbya'SELECT'- construction.AteachCASEyoucanuseintegers,stringsorinteger- variables(ênotÇstring-variables).Onlythefirstfourbytesofastring canbeused.TheeditorwillnotacceptsomethinglikeCASE"test2", onlyCASE"test". üë18.PROGRAMLOOPS Ç üCalculationsÇ Trytoremoveallunnecessarycalculationsfromloops,e.g.: FORi=1TO1000 x(i)=2*q*i NEXTi It'sabetterideatocalculate2*qoutsidetheloop: q2=q*2 FORi=1TO1000 x(i)=q2*i NEXTi Alwaystrytoconvertfloatingpointvariablestointegersbeforeentering aloop.Thenyouwillbeabletousethefastinteger-operators.An obviousexamplewouldbeacalculationwithdollars(24.37)thatcouldbe replacedbyacalculationwithcents(2437).Usethismethodifyouknow thelowestpossiblevalueofthefloatingpointvariable(0.01inthis case)andthendividebythisvalue.Butwatchoutforroundingerrorsand integer-overflow. Powersof2canbecalculatedfastbysettingabit: x%=BSET(0,6) !fasterthanx%=2^6 Andfortheultimatespeed-freaks,multiplyingwithapowerof2is slightlyfasterwithSHL: y%=SHL(x%,3) !fasterthany%=MUL(x%,8) Ofcoursethereisnooverflow-controlifyouuseSHL(orMUL). Sometimes,calculationsinaloopcanbereplacedbyalook-uptable: FORi=1TO1000 y%(i)=x|(i)^2 NEXTi First,createatableofsquares: DIMsquare%(255) FORi=0TO255 square%(i)=i*i NEXTi Thenusethistableintheloop: FORi=1TO1000 y%(i)=square%(x|(i)) NEXTi üFOR...NEXTÇ IuselocalvariablesinProceduresifpossible.Butifyouintendto compiletheprogramlater,youshoulddeclarethecounterinaFOR... NEXTloopasaêglobalÇvariable.Inthecompiledprogram,theloopwillbe executedfaster! ÇIfyouusefloatingpointcount-variablesinaFOR...NEXTloop(orany otherloop),youcouldencounterunexpectedproblems: FORi#=0.1TO0.9STEP0.1 PRINTi# NEXTi# Youwouldexpect0.9astheresultofthelastaddition(0.8+0.1),but 0.9isneverprinted!ThisisnotabuginGFA-Basic,butcausedbythe internal(binary)representationoffloatingpointnumbers.Thelast additionresultsinanumberslightlylargerthan0.9andthereforethe loopisleftafterprinting0.8.Ifyouinserttheline  i#=ROUND(i#,14) intheloop,youcansolvethisproblem.Butthebestsolutionistoavoid floatingpointcount-variablesinloops.Integercount-variablesaremuch faster.Youcouldeasilychangetheloopto: FORi=1TO9 PRINTUSING"#.#";i/10 NEXTi Onemoretime:'i'isaword-variable,becauseIuseword-variablesas thedefaultfornumber-variableswithoutpostfix. IfyouuseafloatingpointvariableinaREPEATUNTILloop,youcanavoid theroundingerrorbyusingthespecialoperator'==': i#=0 REPEAT i#=i#+0.1 PRINTi# UNTILi#==0.9 Butyoucan'tusethe'=='-operatorinaFOR...NEXTloop. Inthefollowingtwoexamplesabyte-variableisusedasthecounter: FORi|=5DOWNTO-1 PRINTi| NEXTi| ' FORi|=250TO256 PRINTi| NEXTi| Ofcourse,abyte-variablecannothaveavalueof-1or256.GFAdoesênotÇ abortwithanerror-message,butskipstheloops.Notatruebugperhaps, butclose. üLoopsÇ AlthoughyoucanusemanydifferentloopsinGFA-Basic3.0,thereare basicallyonlytwovarieties.Youcanfirsttestacondition,andthen eithercontinueorleavetheloop.Oryoucanfirstentertheloop,and thentestaconditiontodecideifyouaregoingtocontinueorleave. InaninterpretedprogramthefirstchoiceisthefastFOR...NEXTloop, thenthe(slower)REPEAT...UNTILloopandfinallythe(slowest)WHILE ...WENDloop.Inacompiledprogramallloopsareexecutedequallyfast! IfyouuseaDO...LOOP,anEXITIFconditionwillalwaystakesomeextra time. ÇTrytoavoidaênegativeÇtestinaloop,asthiswilltakemoretime.E.g. replace: WHILENOTcondition! (...) WEND bythemuchfaster: DOUNTILcondition! (...) LOOP Orsimilarlyreplace: REPEAT (...) UNTILNOTcondition! bythefaster: DO (...) LOOPWHILEcondition! Finally,youcouldcombinethetestofoneconditionatthestartofthe loopwiththetestofanotherconditionattheendoftheloop: DOUNTILcondition_1! (...) LOOPWHILEcondition_2! üë19.PROGRAMCONTROL Ç üGOSUBÇ AProcedurecanbecalledinoneofthefollowingways: GOSUBproc @proc proc Ipreferthesecondmethod,becausethisisspottedeasilyinalisting. Also,thesamemethodcanbeusedtocallafunction. üONBREAKGOSUBÇ Youcan'tstopaprogramifarecursivelycalledfunctionisexecuted(?). UseONBREAKCONTtopreventcallingtheBreak-Proceduretwice.Nobodycan releasethe<Control><Shift><Alternate>keysfastenough: ONBREAKGOSUBbreak (...) PROCEDUREbreak ONBREAKCONT (...) ONBREAKGOSUBbreak RETURN InthiscasetheBreak-Procedureisactivatedagainbeforeleavingthe Procedure.StudytheStandardProcedureBreak(inoneoftheSTANxxxx.LST- files)foranexampleofthismethod. üERRORÇ YoucansimulateERRORswithvaluesfrom-127to127.ForGFA-errorsuse valuesfrom0to93,forbomb-errors102(2bombs)to109(9bombs)and forTOS-errors-1to-67. üEVERYandAFTERÇ It'snotpossibletouseEVERYandAFTERatthesametime.Bothcommands don'tworkduringalongPAUSEorDELAY(oranyothercommandthattakesa lotoftime).YoucanonlycallProcedureswithoutparameters.Don'tmake theProceduretoolong,oritmaybecalledwhilebeingprocessed! Inacompiledprogramyouhavetoincorporate'$I+U+',orEVERYandAFTER can'tbeused. üGOTOÇ Youcan'tuseGOTOinaProcedure,aFunctionoraFOR...NEXTloop. üDELAYÇ TheDELAY-commanddoesnotoperatecorrectlyinversion3.07ofGFA-Basic. DuringDELAYaBreakisimpossible.Anastierbugistheappearanceofthe mouse-cursorduringDELAY,evenafterHIDEM.YouareadvisedtousePAUSE instead. üCHAINÇ InGFA-BasicallvariablesandarraysarelostafterCHAINingthenext program.However,youcouldusethe160-bytebufferofthescrap-library topassashortmessagetothenextprogram: buffer$=SPACE$(160) !160bytesmaximum?? message$="thismessagewassentbythepreviousprogram" message$=message$+CHR$(0) LSETbuffer$=message$ r%=SCRP_WRITE(buffer$) !r%=0iferror CHAINfile$ Readthemessagewith: buffer$=SPACE$(160) r%=SCRP_READ(buffer$) message$=CHAR{V:buffer$} Theuseofthisbufferiscompletelyillegal,butwhocaresifyoudon't useascrap-library?UnfortunatelytheGFA-editorseemstothinksotoo, soyoushouldexperimentalittlebeforetrustingthismethod. üEXECÇ Ifyouaregoingtorunanotherprogrammorethanonce,you'llhavetouse EXEC3: base%=EXEC(3,file$,"","") !load,butdon'tstartyet base$=STR$(base%) cmdl$=CHR$(LEN(base$)+1)+base$ !createcommandline (...) r%=EXEC(4,"",cmdl$,"") !nowrunit Thevariabler%containsavaluereturnedbytheprogram(or-39ifnot enoughmemorywasavailable).Repeatthelastlineifyouwanttorunthe loadedprogramagain.OfcourseyoushoulduseEXEC0ifyou'regoingto runtheprogramonetimeonly.Readtheparagraph'RESERVE'ifyouare goingtouseEXEC3. Ifyoucalla'*.PRG'-programwithEXEC0,youpassthenull-string("") asthecommand-line.Youneedthecommand-lineonlyifyoucalla'*.TTP'- program.Thecommand-lineisconvertedtouppercaseandcan'texceed125 bytes.Thefirstbyteofthecommand-line(usually)determinesthelength oftheline,sothecommand-linecan'tcontainmorethan124characters. YoucanusethisinaTTP-program(compiledGFA-Basicprogram,extension changedtoTTP),butit'seasiertoreadthecommand-linewith: cmdl$=CHAR{BASEPAGE+&H81} üë20.GRAPHICS Ç üSETCOLORandVSETCOLORÇ WithcommandslikeCOLOR,DEFTEXT,DEFFILL,etc.,youuseaVDIcolour- index.UnfortunatelySETCOLORusesadifferenttable: VDIcolour-index :0123456789101112131415 SETCOLOR(Lowrez) :0151246357891012141113 SETCOLOR(Medrez) :0312 Fromthistableitfollowsyouwouldhavetouse'SETCOLOR2,r,g,b'to changecolour-indexê3Ç.Bytheway,allLine-AcommandsusetheSETCOLOR- tableaswell!Thisisnota"bug",butaconsequenceoftwodifferent colour-tablesthatareusedbyGEMDOSandGEM.Youareadvisedtouse: VSETCOLORindex,r,g,b Thisindexisexactlythesameasthecolour-index,soyouwoulduse 'VSETCOLOR2,r,g,b'inordertochangecolour-index2.Ifyoulike,you couldusethehexadecimal3-bytemix-value: VSETCOLORindex,&Hrgb Butyouwon'tlikeitatall,becausethisdoesn'tworkproperly.GFA- Basicswapsther-andg-byte,soyouwouldhavetouse: VSETCOLORindex,&Hbgr Betteravoidthismethod,oryou'llexperiencecolour-changesifGFA correctsthisbuginafutureversion. InHighresolutionyoucaninvertthescreen-colourswith: VSETCOLOR0,0 !reverseHigh-screen(blackbackground) VSETCOLOR1,0 !normalHigh-screen(blackletters) Aninvertedscreenisperhapsslightlylesssuitablefortext,but graphicslooksuperb. Colour-index0determinesthecolourofthebackgroundinLowandMedium resolution.Thisindexalsodeterminesthecolouroftheborderonyour screen.Youcanchangethiscolour,althoughyoucan'tdraworPRINTon thescreen-borderofyourcolourmonitor.ThecolourofallPRINTedtext isdeterminedbycolour-index1,unlessyouusethe'Escb'command(read theparagraph'PRINT'againifyourlong-termmemoryistooshort): VSETCOLOR0,r,g,b !changecolourofbackground VSETCOLOR1,r,g,b !changecolourofêallÇPRINTedtext üPaletteÇ Beforechangingcolours,youshouldalwayssavethecurrentpalette.And dorestoretheoldpalettebeforetheuserexitstheprogram.Ihate programsthatreturntoapinkoryellowdesktop.Youcanstorethe paletteeitherinanintegerarrayorinastring,usingXBIOS7 (Setcolor): Ç PROCEDURE save.palette LOCAL i ERASE old.palette%() DIM old.palette%(15) FOR i=0 TO 15 old.palette%(i)=XBIOS(7,i,-1) NEXT i RETURN ' PROCEDURE make.palette.string(VAR pal$) LOCAL n pal$="" FOR n=0 TO 15 pal$=pal$+MKI$(XBIOS(7,n,-1)) NEXT n RETURN Thestring-methodiscompatiblewithDegas.Restoretheoldpalettewith thecorrespondingProcedures: PROCEDURE restore.palette LOCAL i FOR i=0 TO 15 VOID XBIOS(7,i,old.palette%(i)) NEXT i RETURN ' PROCEDURE change.palette(pal.string$) VOID XBIOS(6,L:VARPTR(pal.string$)) RETURN YoucouldalsousetheStandardProcedureStandard.low.colorsor Standard.med.colorstorestorethedefaultpalette.Youcanfindthese ProceduresintheSTANxxxx.LST-files. Youcanexaminethergb-valueofacertainVDIcolour-indexwith: PROCEDURE rgb.value(index,VAR rgb$) LOCAL col% col%=XBIOS(7,color.index(index),-1) rgb$=RIGHT$(HEX$(col%),3) RETURN TheStandardArraycolor.index()isusedtoconverttheVDIcolour-index. AcompletelynewpaletteforMediumresolutioncanbeinstalledwith: PROCEDURE new.med.colors LOCAL n,r,g,b,col$ RESTORE med.new.col.data FOR n=0 TO 3 READ col$ r=VAL(LEFT$(col$)) g=VAL(MID$(col$,2,1)) b=VAL(RIGHT$(col$)) VSETCOLORn,r,g,b NEXT n med.new.col.data DATA000,000,000,000 RETURN ÇYoucanshowthecurrentpaletteonthescreenwiththeProcedure Palette.box: PROCEDURE palette.box(x,y,h,w) ' *** left upper corner of rectangle at x,y ' *** rectangle-height h; width of one colour-box w LOCAL arect.fill,fill.adr%,i,x1,x2 x2=x+16*w+2 COLOR black BOX x,y,x2,y+h arect.fill=-1 f%=V:arect.fill IF low.res! FOR i=0 TO 15 x1=ADD(SUCC(x),MUL(i,w)) ARECT x1,SUCC(y),ADD(x1,w),PRED(ADD(y,h)),color.index(i),0,f%,0 NEXT i ELSE IF med.res! FOR i=0 TO 3 x1=ADD(SUCC(x),MUL(i,w)) ARECT x1,SUCC(y),ADD(x1,w),PRED(ADD(y,h)),color.index(i),0,f%,0 NEXT i ENDIF RETURN Youcandarkenthescreenbydimmingallcolourssimultaneouslywiththe ProcedureDim.colors: PROCEDURE dim.colors(reg1,reg2,val) ' *** dim colours from VDI colour-index reg1 to reg2 with val ' *** for val=1 colour 254 (rgb) will become 143 LOCAL i,r,g,b FOR i=reg1 TO reg2 @rgb.value(i,rgb$) r=MAX(PRED(VAL(LEFT$(rgb$))),0) g=MAX(PRED(VAL(MID$(rgb$,2,1))),0) b=MAX(PRED(VAL(RIGHT$(rgb$))),0) VSETCOLOR i,r,g,b NEXT i RETURN NothingisimpossibleinGFA-Basic,evencolour-cyclingiseasywith EVERY intheProcedureColor.cycle: PROCEDURE color.cycle(reg1,reg2,time) ' *** cycles colours from VDI colour-index reg1 to reg2 ' *** global : COLOR.CYCLE! COL.REG1 COL.REG2 IF NOT color.cycle! col.reg1=reg1 col.reg2=reg2 color.cycle!=TRUE EVERY time GOSUB cycle.once ELSE color.cycle!=FALSE EVERY STOP ENDIF RETURN Ç ' PROCEDURE cycle.once LOCAL col1%,col2% col1%=XBIOS(7,color.index(col.reg2),-1) FOR reg=col.reg1 TO PRED(col.reg2) col2%=XBIOS(7,color.index(reg),-1) ~XBIOS(7,color.index(reg),col1%) SWAP col1%,col2% NEXT reg ~XBIOS(7,color.index(col.reg2),col1%) RETURN CalltheProcedureColor.cycleagaintostopthecolour-cycling. üDEFMARKÇ Thepointasmark-symbol(No.1)cannotbeenlarged.Othermark-symbols canbeenlarged,butalllinesinthesymbolretainawidthofonepixel. Thesizeofasymbolmustbeamultipleof11plus6:0,17,28,39,50. Foravalueinbetween,thepriorallowedsizeischosen.Perhapsthereis somemagichiddenintheallowedsizes,oramImissingsomething? üDEFFILLÇ Ifyouhaven'tdefinedyourownFill-pattern,theAtari-symbolwillbe usedafterDEFFILL1,4,x.ThedesktopFill-patternisDEFFILL1,2,4. TheFill-patternstringcanconsistof16,32or64words(MKI$-format). Word1to16isneededforbitplane0(Highresolution),word17to32for bitplane1(Mediumresolution)andword33to64forthebitplanes2and3 (Lowresolution).Inallresolutions,thepatternoccupiesarectangleof 16x16pixelsonthescreen.Thesame16x16rectangleisalsousedforthe mouse-cursorandsprites.YoucanalwaysuseaFill-patterninaêlowerÇ resolution,e.g.aHigh-patterninMediumorLowresolution,butnotthe otherwayaround.ExaminethethreeProceduresInitio.high.fill1, Initio.med.fill1andInitio.low.fill1toseehoweasyyoucandesignyour ownFill-patterns.There'sgoldinthemtharFills.Youcouldsurprisethe userwithabomb-pattern: PROCEDURE initio.bomb.fill ' *** global : BOMB.FILL$ RESTORE bomb.fill @make.high.fill(bomb.fill$)  bomb.fill: DATA 0000011000000000 DATA0010100100000000 DATA0000000010000000 DATA0100100001000000 DATA 0001000111110000 DATA 0000000111110000 DATA 0000011111111100 DATA 0000111111111110 DATA 0000110111111110 DATA 0001111111111111 Ç DATA 0001111111101111 DATA 0000111111101110 DATA 0000111111011110 DATA 0000011111111100 DATA 0000001111111000 DATA 0000000011100000 RETURN ' PROCEDURE make.high.fill(VAR fill$) LOCAL i,pat$,pat% CLR fill$ FOR i=1 TO 16 READ pat$ pat%=VAL("&X"+pat$) fill$=fill$+MKI$(pat%) NEXT i RETURN Becareful,ascreenfilledwiththispatternmightprovokeaheart- attack.Ifitdoesn't,youcouldtrythefollowingdirtytrick(High resolutiononly)withtheProceduresBusyandAchtung: @busy !lookslikethecomputerisverybusy ~INP(2) !butnothinghappens,untiltheuserpressesakey... @achtung PAUSE500 CLS PRINT"Thankyouforyourpatience,I'mnotbusyanymore..." PAUSE150 ManyFill-patternsareavailableasfiles.Youcanusethesewith somethinglikeProcedureInitio.fill1: PROCEDURE initio.fill1(VAR pattern$) LOCAL bytes bytes=32 ! 32 bytes for High resolution ' *** load Fill-pattern (32 bytes for High resolution) here INLINE fill1%,32 pattern$=STRING$(bytes,0) BMOVE fill1%,V:pattern$,bytes DEFFILL ,pattern$ RETURN FILLingascreenwithapatterntakessometime,especiallyinHigh resolution.Usethefollowingmethodforalmostimmediatefillingofthe entireHighresolutionscreen: PROCEDUREfull.fill(fill%)  ACLIP1,0,0,639,399  ARECT0,0,639,399,1,0,fill%,15  ACLIP0,0,0,639,399 RETURN Fill%istheaddressofaFILL-pattern(32bytes).Thisveryfast alternativeFill-methodworksinHighresolutiononly. üDEFLINEÇ After'DEFLINE,n'allhorizontallineshaveawidthofnpixels(nshould beodd),exceptinMediumresolution.Butifnislargerthan1,all verticallinesaren+2pixelswide!Ihavetroublecountingthepixels inMediumresolution.Ithinkthewidthofhorizontallinesis: n: 13579 width : 11335etc. Isthisdocumentedanywhere? YoudefineyourownLine-patternsbyusinganegative16-bitvalue(from -&X1to-&X1111111111111111).Eachsetbitcorrespondswithapixelinthe Line-pattern(Highresolution).Thehighestbit(15)correspondswiththe leftmostpixelofthepattern.Don'tgetconfusediftheeditorchanges thenegativebinarynumberyouenteredasapattern.Theeditorusesa specialnotationfornegativebinarynumbers. GFA-Basicrepresentsintegernumbersasbinarystringsof32bits.The mostsignificantbit(31)determinesthesignoftheinteger.Ifthisbit is0,theremaining31bitsrepresentan"ordinary"positivenumber.But ifthemostsignificantbitis1,theremainderisanegativenumberin 'two'scomplement'notation.Iwon'ttrytoexplainthat.Inanycase,the nexttimeyoutype-&X111andafriendiswatchingyou,don'tblinkyour eyes,butcasuallyremark"ofcoursetheeditorconvertsthisintotwo's complementnotation".That'salsothereasonGFA-Basiccanworkwith integersfrom-(2^31)to+(2^31)-1. üDEFTEXTÇ Insomepublicationsyoucanreadabout'shadowedtext'(style=32),but unfortunatelyourGEMdoesn'tknowthisstyle.Youcanevenfindthemask forshadowedtextwithWORD{L~A+92},butit's0. Ineversucceededinfindingthecurrenttext-stylewithVDISYS38 (vqt_attributes).EitherabuginGEMormymistake.Idon'twanttoknow, becausetheeasywayis: txt.style=WORD{L~A+90} ThiscouldbeimportantifyouintendtouseDEFTEXTinaProcedure,but wouldliketorestoretheoriginalDEFTEXT-settingsbeforeleavingthe Procedure. WithDEFTEXTyoucansettheheightofTEXT-letters.Aletteroccupies morespacethough,determinedbytheletter-box: êletter-heightÇ êletter-boxÇ êsystem-fontÇ 4 6x6 icon 6 8x8 Medium&Lowrez 13 8x16 Highresolution Theletter-heightisthedistancefromDescent-LinetoAscent-Line,but theBottom-LineandTop-Linelieatleastonepixellower/higher.The heightoftheletter-boxisthedistancefromBottom-LinetoTop-Line.  ÇMostlettersrestontheBase-Line,butletterswithadescender(g,j,p, etc.)restontheDescent-Line.Ifyouarestillwithme,fromtopto bottomwehavethefollowinglines: Top-Line Ascent-Line Base-Line Descent-Line Bottom-Line Dropmealineifyoudon'tunderstandthis. üGRAPHMODEÇ IfyoudrawarectanglewithBOXinGRAPHMODE3(Xor-mode),thepixelin theleftuppercornerisnotdrawn.Actuallythispixelisdrawntwice, andinGRAPHMODE3thismeansthepixeldisappears.UsePLOTtodrawthis pixel: GRAPHMODE3 BOXx1,y1,x2,y2 PLOTx1,y1 !andfillthegap WithPBOXinGRAPHMODE3you'llalsogettroubleinthesamecorner.Avoid thisbyusingthecommand'BOUNDARY0'first: GRAPHMODE3 BOUNDARY0 PBOX50,50,100,100 GRAPHMODE3isespeciallyusefulifyoumakeatemporarydrawing.Drawthe samepictureasecondtimetorestoretheoriginalscreen.ExamineProce- dureslikeRubber.line,Draw.boxandDrag.boxforexamplesofthismethod. TheProcedureRubber.lineisusedtodrawalinefrom(x,y)tothemouse- cursor: PROCEDURE rubber.line(x,y,VAR x2,y2) LOCAL x1,y1,x2,y2,k GRAPHMODE 3 DEFMOUSE 3 SHOWM MOUSE x1,y1,k REPEAT !mainloop LINE x,y,x1,y1 !drawline REPEAT MOUSE x2,y2,k UNTIL x2<>x1 OR y2<>y1 OR k>0 !mousemoved LINE x,y,x1,y1 !undrawline x1=x2 y1=y2 UNTIL k>0 !mouse-click:ready(x2andy2returned) GRAPHMODE 1 LINE x,y,x2,y2 !thisisit HIDEM DEFMOUSE 0 PAUSE 10 RETURN ÇYoucouldalsousethe'GRAPHMODE3'-methodforanimation,buttheXBIOS5 (Setscreen)methodismoresuitable. Don'ttrytodrawinGRAPHMODE3withalinewidthgreaterthan1pixel. GEMwillsurpriseyouwithsomemodernartifyoucan'tresistthe temptation. Ifyouwanttoconfirmaparticularchoiceoftheuser,youcaninvertthe relevantpartofthescreenwiththeProcedureInvert.block.Callthis Procedureagainwiththesameparameterstorestoretheoriginalscreen: PROCEDURE invert.block(x1,y1,x2,y2,color) GRAPHMODE 3 DEFFILL color,1 BOUNDARY 0 PBOX x1,y1,x2,y2 BOUNDARY 1 GRAPHMODE 1 RETURN Youcan'greyout'anunavailableoptiononthescreenwith: PROCEDURE block.dimmer(x1,y1,x2,y2,color) GRAPHMODE 3 DEFFILL color,2,2 BOUNDARY 0 PBOX x1,y1,x2,y2 BOUNDARY 1 GRAPHMODE 1 RETURN CallthisProcedureagaintorestorethescreen. Theentire(Highresolution)screencanbedimmedwith: PROCEDURE screen.dimmer ' *** global : DIMMER.SCREEN$DIMMER.SWITCH! IF dimmer.switch!  SPUT dimmer.screen$ dimmer.switch!=FALSE ELSE SGET dimmer.screen$ GRAPHMODE 4 DEFFILL 1,2,4 PBOX 0,0,639,399 dimmer.switch!=TRUE ENDIF RETURN ThescreenwillberestoredifyoucalltheProcedureagain. üPLOTandDRAWÇ Youcanuseboth'PLOTx,y'and'DRAWx,y'tosetapointonthescreen. Thesizeofthepointcanbechanged: DEFLINE,size,2,2 !changesizeofpoints ÇButtheshapesyou'llseedon'tlooklikepointsanymore,duetothesame problemasdescribedintheparagraph'DEFLINE'.UsePCIRCLEforproper fatpoints. üPCIRCLEÇ WithCLIPon,aPCIRCLEtouchingtheupperscreen-borderisnotfilled properlyinHighresolution: CLIP0,0,640,400 PCIRCLE0,0,50 Idon'tknowifweshouldblameGFAorGEMfornotfillingthetwotop- linesinthecircle. üCURVEÇ WiththecommandCURVEyoucandrawaBezier-curve: CURVEx1,y1,x2,y2,x3,y3,x4,y4 TheBezier-curvestartsat(x1,y1)andendsat(x4,y4).Theothertwo pointsactlikelittlemagnets.Youcanalsousethiscommandtodrawa 'normal'curvebetweentwopointsbylettingthepoints(x3,y3)and (x4,y4)coincide.TrythefollowingtoseewhatImean: GRAPHMODE3 MOUSEx2,y2,k DO CURVE10,100,x2,y2,110,100,110,100 !drawcurve REPEAT MOUSEx,y,k UNTILx<>x2ORy<>y2 CURVE10,100,x2,y2,110,100,110,100 !erasecurve x2=x y2=y LOOP Thismethodcouldbeusedtodrawlargeletters. üTEXTÇ ThecoordinatesusedwithTEXTdeterminethestartoftheêBase-LineÇofthe text.Thedescendersofletterslike'g','j',and'p'liebelowtheBase- Line.Thisisespeciallyimportant,nottosayfrustrating,ifyouuse TEXTwithanangleof90,180or270degrees.Thetextrotatesanticlock⑨ wisearoundtheTEXT-coordinates! IfyouintendtocombinePRINTedtextwithTEXT,youprobablywilllike theProcedureText.atastheanalogueof'PRINTAT': PROCEDURE text.at(c,l,t$) TEXT (c-1)*char.width,l*char.height+3*high.res!+2*(NOT high.res!),t$ RETURN ÇYoucanuseTEXTtoprint"digital"numbers(ASCII-code16-25): FUNCTION digital$(number$) LOCAL dig$,i CLR dig$ FOR i=1 TO LEN(number$) dig$=dig$+CHR$(BCLR(ASC(MID$(number$,i,1)),5)) NEXT i RETURN dig$ ENDFUNC UsethisFunctionasfollows: TEXT x,y,@digital$("1237") üSPRITEÇ YoucoulddesignandsavespritesäinvitroÇwithoneofthemanySprite- editorsthatareavailable.OryoucanusesomethingliketheProcedure Initio.sprite1tocreateaspriteäinvivoÇ.ComparethisProcedurealso withtheProcedureInitio.mouse1: PROCEDURE initio.sprite1 ' *** global : SPRITE1$ RESTORE pattern.sprite1 @make.sprite(sprite1$) pattern.sprite1: ' *** x,y,mode(0=normal;1=XOR),mask-colour,sprite-colour DATA 0,0,0,0,1 ' *** mask-pattern (1 = pixel on , 0 = pixel off) DATA 0000000000000000 DATA 0000000000000000 DATA 0000000000000000 DATA 0000000000000000 DATA 0000000000000000 DATA 0000000000000000 DATA 0000000000000000 DATA 0000000000000000 DATA 0000000000000000 DATA 0000000000000000 DATA 0000000000000000 DATA 0000000000000000 DATA 0000000000000000 DATA 0000000000000000 DATA 0000000000000000 DATA 0000000000000000 ' *** sprite-pattern DATA 0000000000000000 DATA 0000000000000000 DATA 0000000000000000 DATA 0000000000000000 DATA 0000000000000000 DATA 0000000000000000 DATA 0000000000000000 DATA 0000000000000000 DATA 0000000000000000 DATA 0000000000000000 Ç DATA 0000000000000000 DATA 0000000000000000 DATA 0000000000000000 DATA 0000000000000000 DATA 0000000000000000 DATA 0000000000000000 RETURN ' PROCEDURE make.sprite(VAR s$) LOCAL x,y,mode,msk.color,spr.color,n,msk%,spr%,msk.pat$,spr.pat$ LOCALmsk$,spr$,pat$ CLR msk.pat$,spr.pat$,pat$ READ x,y,mode,msk.color,spr.color FOR n=1 TO 16 READ msk$ msk%=VAL("&X"+msk$) msk.pat$=msk.pat$+MKI$(msk%) NEXT n FOR n=1 TO 16 READ spr$ spr%=VAL("&X"+spr$) spr.pat$=spr.pat$+MKI$(spr%) NEXT n FOR n=1 TO 16 pat$=pat$+MID$(msk.pat$,n*2-1,2)+MID$(spr.pat$,n*2-1,2) NEXT n s$=MKI$(x)+MKI$(y)+MKI$(mode)+MKI$(color.index(msk.color)) s$=s$+MKI$(color.index(spr.color))+pat$ RETURN Themaskshouldbeanexactcopyofthesprite-patternifyouneeda transparantsprite.Leavethemaskempty(all'0')andthespritewill disappearbehindobjectsonthescreen.Fillthemaskwith'1'andthe 16x16spritewillalwaysremainvisible.Switchmask-andsprite-colourin thefirstDATA-linetocreatea"reverse"sprite.OruseanyVDIcolour- indexthatisavailableinthecurrentresolution. Ifyouputaspriteonthescreen,thebackground(16x16pixels)is temporarilysaved.Usingmorethanonespritesimultaneously,itis essentialyouremovespritesinreverseorder.Thisisnecessarybecausea spritecouldoverlapanothersprite.Removingthetopspritefirstensures thattheoriginalbackgroundwillreappearafterremovingthefirst sprite,e.g.: DO (...) SPRITEs2$ !removesprites... SPRITEs1$ VSYNC !preventsblinking,butslowsdown SPRITEs1$,x1,y1 !drawsprites... SPRITEs2$,x2,y2 (...) LOOP üVQT_EXTENTÇ ThefunctionVQT_EXTENTcanbeusedifyouwouldliketodrawarectangle aroundatext-string: ~VQT_EXTENT(txt$,x1,y1,x2,y2,x3,y3,x4,y4) Thecoordinatesofthefourcornersdependontheangleofthetext(0, 90,180or270degrees)andofcourseonthesizeofthetext.Thepoint (x1,y1)isthelowerleftcorneroftheimaginaryrectanglearoundthe textandtheotherpointsarearrangedanticlockwisearoundthetext- string.BecausethetextrotatesaroundtheTEXT-coordinates(startofthe Base-Line),itwilltakesometrialanderrortodeterminethecorrect positionoftherectangleiftheangleisnot0degrees.Inthefollowing tableyou'llfindthe"true"originoftherectangle,thewidthandthe heightoftherectangle,andalsotheactualpositionofthelowerleft cornerofthetext-block(x1,y1): êangleÇ êposition(x1,y1)Ç êoriginÇ êwidthÇ êheightÇ 0 lowerleft x1,y1 x2 y4 900 lowerright x4,y4 x1 y3 1800 upperright x3,y3 x4 y2 2700 upperleft x2,y2 x3 x4 Thecoordinatesoftheoriginare(0,0),sowithanangleof0degrees bothx1andy1are0.Therectanglerestsonthex-axis,whiletheleft sidecoincideswiththey-axis.Thisisa"mathematical"y-axis,nota "screen"y-axis.Thismeansyougoupwardsforpositivey-values.Foran angleof0degreesthecoordinateswillbe: (x4,y4)..(x3,y3) .TEXTBLOCK. (x1,y1)(x2,y2) Ifyouunderstandthetable,youshouldbesurprisedbytheheight'x4' insteadof'y1'atanangleof270degrees.IthinkIdiscoveredabugin GEMhere.CorrectGEMbychangingthefollowingvariablesifanangleof 270degreesisused: y1=x4 SWAPx4,y4 Now,theheightis'y1'asyoususpected.Clever,aren'twe?Ihavenot beenabletoconfirmmydiscovery.Noneofmyreference-booksmentionthe bug. üLine-AÇ TheLine-AcommandsarefasterthanthecorrespondingVDI-commandsinGFA- Basic.ThedifferenceshouldbeevengreaterafterloadingGDOS(?).In thefollowingtableyoucanfindhowmanytimesfastertheLine-Acommand is: PSET/PLOT=3 PTST/POINT=2 HLINE/LINE=2 ARECT/PBOX=1.5 ThesyntaxofLine-Acommandsismorecomplicated,butthat'snoproblem forusGFA-experts.Line-Acommandsusethe'SETCOLOR-index',soyou'll probablyneedtheStandardArraycolor.index(). üHLINEÇ AnadditionaladvantageofthecommandsHLINE,ARECTandAPOLYisthatyou don'thavetochangetheDEFFILL-parametersinthemainprogram.Forsolid horizontallines,use: pattern=-1 adr%=V:pattern HLINEx1,y,x2,color,mode,adr%,0 Youcan'tuse&X1111111111111111(16bits)forthepattern,becausebit15 ofaword-variableisaflagforanegativenumber.Yes,that'swhythe largestpositivewordis2^15-1(32767).Thesolutiontothislittle problemistoassign-1totheword-variable.Youhavemyword,nowall16 bitsare1.UseBIN$ifyoudon'tbelieveme. Forverycomplicatedpatternsyoucoulduseaword-array: DIMpattern(i) adr%=V:pattern(0) (...) !putfill-patterninpattern(0)topattern(i) HLINEx1,y,x2,color,mode,adr%,i üACHARÇüandATEXTÇ It'sdifficulttocombinetheLine-AcommandsACHARandATEXTwithTEXT. ThecoordinatesusedwithACHARandATEXTdeterminethepositionofthe leftuppercornerofthe(first)letter-box.That'stheTop-Line,ênotÇthe Base-Line. Youcan'tusethetext-styleunderlined(8)withACHARandATEXT.Probably aGFA-bug. üGETandPUTÇ Youcouldsavearectangularpartofthescreenasfollows: GETx1,y1,x2,y2,pic$ BSAVEfile$,V:pic$,LEN(pic$) !usetheextensionPUTinthefilename Later,youcouldputthesavedpicturebackonthescreenwith: OPEN"I",#1,file$ LETbytes%=LOF(#1) !howmanybytesneeded? CLOSE#1 picture$=SPACE$(bytes%) !reservesomespace, BLOADfile$,V:picture$ !loadthepicture PUTx,y,picture$ !andlookatit TheProceduresMessage,Warning,Message.onandMessage.offuseGETand PUTtosaveandlaterrestorethepartofthescreenthatisusedfor text. ÇAGET-stringstartswiththreewordsforwidth,heightandnumberof bitplanes.Thenumberofbitplanesisdeterminedbytheresolution:1for High,2forMediumand4forLow.Afterthesethreewordsfollowsthe actualpictureasalistofwords.Asthepicture-widthisnotnecessarily amultipleof16,anybitsbeyondtherightborderwillbeignoredbythe PUT-command. HereistheconnectionbetweenGRAPHMODEandPUT-mode: êGRAPHMODEÇ êPUT-modeÇ 1 3(default) 2 7 3 6 4 13  IhaveencounteredafewprogramsinGFA-Basic2.0wherePUTwasused justoutsidethescreen.InGFA-Basic3.0theprogramdidn'twork.The sameoccurredinaprogramwhereapicturewasBLOADedafewbytesbefore thescreen-RAM.Idon'tunderstandwhyGFA-Basic3.0doesn'tacceptthis, asthereissomeunusedspacethere(readtheparagraph'RAM'),butI've learnedtocorrectthiswhenIconvertaprogramfromGFA-Basic2.0to version3.0. üDegas-PicturesÇ ADegaspicture-filecontainsnotonlytheactualpicture(sameformatas SGET-picture),butalsothecolour-palette.UsetheProcedureShow.degas toloadandshowaDegas-picture: PROCEDURE show.degas(degas$) LOCAL degas.picture$,degas.picture%,degas.palette$ LOCALdegas.palette% degas.picture$=SPACE$(32000) degas.picture%=VARPTR(degas.picture$) degas.palette$=SPACE$(32) degas.palette%=VARPTR(degas.palette$) OPEN "I",#90,degas$ SEEK #90,2 !skipresolution BGET #90,degas.palette%,32 ! load palette of picture SEEK #90,34 BGET #90,degas.picture%,32000 ! load actual picture CLOSE #90 ~XBIOS(6,L:degas.palette%) ! change palette SPUT degas.picture$ ! show the picture RETURN TheoriginalDegas-fileshavealengthof32034bytes: 1word -resolution 16words -palette 16000words -picturedata YoucanuseBTSTtochecktheresolution(bit0=Low,bit1=Medium,bit 2=High),butyoucouldalsolookattheextensionofthefilename (PI1/PI2/PI3forLow/Medium/High).InthesecondDegas-version(Degas Elite),16wordsfor"colour-animation"canbeaddedafterthepicture data. ÇADegasElitepicturecan(andreallyshould!)besavedinacompressed format.TheextensionsPC1/PC2/PC3areusedforLow/Medium/High resolution.Also,thehighestbitoftheresolution-wordissetasaflag foracompressedpicture.WiththeProcedureShow.comp.degasyoucanload andshowacompressedDegas-picture. üNeochrome-PicturesÇ Sometimesthe"Neochrome"-formatisusedforpictures(32128bytes): 1integer -resolution(0/1/2forLow/Medium/High) 16words -palette 12bytes -filename(nnnnnnnn.eee) 4bytes+1word -colouranimationdata 18integers -reserved 16000words -picturedata üVSYNCÇ TheVSYNC-commandisusefulifyouwanttopreventirritatingblinking duringanimation.AlwaysVSYNCbeforedrawinganewpictureinan animationsequence(includingSPRITE-animation).Theprogramisslowed downofcourse,becauseitwaitsforaverticalblankinterruptbefore startingtodraw.Butitlooksmuchnicer. üScrollÇ WithBMOVEandRC_COPYyoucanaccomplishprettysmoothscrolling.GET/PUT istooslow,andonlyworksonthelogicalscreen.BITBLTismore flexible,butalsomorecomplicated.Andnotfaster(?).Studythe ProceduresScroll.upandScroll.downtoseehowyoucouldscrollthe entirescreenupordown: PROCEDURE scroll.up(scroll.lines,scroll.color) LOCAL n,bytes,move.bytes,source% IF high.res! LET bytes=80*scroll.lines ELSE LET bytes=160*scroll.lines ENDIF move.bytes=32000-bytes source%=physbase%+bytes VSYNC BMOVE source%,physbase%,move.bytes DEFFILL scroll.color PBOX 0,scrn.y.max-scroll.lines+1,scrn.x.max,scrn.y.max FOR n=1 TO DIV(scrn.y.max,scroll.lines) VSYNC BMOVE source%,physbase%,move.bytes NEXT n RETURN ÇCananybodyexplaintheinterferencelinesthatsometimesappearduring thescrolling? Severalfade-overeffectscanbefoundintheProceduresUp.scroll, Slider.scroll,etc.MostProcedurescanonlybeusedinHighresolution. Forscrollingofoneormoretext-linesyoucouldusetheProcedures Scroll.text.upandScroll.text.down: PROCEDURE scroll.text.up(begin,end) LOCAL screen%,sx,sy,w,h,dx,dy IF begin>1 AND end>=begin screen%=XBIOS(3) ! logical screen sx=0 sy=(begin-1)*char.height w=scrn.x.max h=(end-begin+1)*char.height dx=0 dy=sy-char.height RC_COPY screen%,sx,sy,w,h TO screen%,dx,dy ELSE PRINT bel$; ENDIF RETURN ThismethodisalsousedintheProcedureDebug. üACLIPÇ Line-Acommandsare'CLIP-sensitive',soyoushouldalwaysuseanappro⑨ priateACLIP-commandbeforeaLine-Acommand.ThefollowingLine-A commandsareênotÇinfluencedbyACLIP:ALINE,HLINE,PSET,PTSTand BITBLT. üBlitterÇ TheBlitter-TOS(1987)allowsyoutoswitchtheBlitteron/off.Icouldn't testthefollowingProcedure,becauseIdon'thaveaBlitter.ButifI understandthefunctionXBIOS64(Blitmode)correctly,youcouldswitch theBlitteronandofffromGFA-Basic: PROCEDUREblitter(switch!) LOCALstatus status=XBIOS(64,-1) IFBTST(status,1) !Blitteravailable? IFswitch! status=BSET(status,0) !Blitteron ELSE status=BCLR(status,0) !Blitteroff ENDIF ~XBIOS(64,status) !doit ENDIF RETURN ÇBytheway,LineAcommandsdonotusetheBlitter.TheBlitter-chip containsahardware-routinethatreplacestheLineABitBlt-function (BITBLTinGFA-Basic).AllMegaST'shaveaBlitterinstalled. üë21.EVENTS Ç üMENU() ÇThereisnoeasywaytotestinaprogramifanaccessoryhasbeen selectedbytheuser.MENU(1)lookspromising,butthevalue40(select accessory)or41(closeaccessory)isonlysenttotheaccessory!It wouldhavebeennicetobeabletodetermineifanaccessoryhasbeen closed,becauseGEMwillcleartheaccessory-windowandwillfillthe spacewiththedesktop-pattern.Noeasysolutionforthisone,sorry.The bestideaprobablyistotestfrequentlywith'IFMENU(1)=20'ifaredraw isnecessary,e.g.: ONMENUMESSAGEGOSUBredraw (...) PROCEDUREredraw IFMENU(1)=20 (...) !redrawscreen ENDIF RETURN Thismethodonlyworksifyouhaveopenedawindow. üONMENUBUTTONÇ ThesyntaxforONMENUBUTTONis: ONMENUBUTTONclicks,button,eventGOSUBproc Forboth'button'and'event'youcanusethenumbers0-3.Thevariable 'clicks'standsfortheêmaximalÇnumberofclicksyouwanttoregister.If youchoose'2',theProcedurewillbecallediftheuserclicksonceor twice: ONMENUBUTTON2,1,1GOSUBproc It'snotpossibletowaitforadouble-click,unlesstheprogamisreally waiting,andnotdoinganythingelse: SELECTEVNT_BUTTON(2,1,1) CASE1 'clickedonce CASE2 'clickedtwice ENDSELECT Butyoucan'tcombinethiswithanONMENUloop. Ifyouusethedescribedmethod: ONMENUBUTTON2,1,1GOSUBproc youcoulduseMENU(15)inthecalledProceduretocheckiftheuser clickedtwice.ThesameProcedurewouldbecalledafterasingleclick, butyoucouldignorethat.Fastenyourseatbeltsnow.Ifyourunsucha programthefirsttime,adoubleclickisênotÇregisteredinMENU(15).If yoususpectabugandruntheprogramagain,MENU(15)worksallright. Nasty. ÇAnotherbug,butthistimeaGEM-bug(Ithink),after: ONMENUBUTTON1,2,2GOSUBproc TheProcedureiscalledimmediately,whethertherightmouse-buttonwas pressedornot. IfyouwanttoswitchONMENUBUTTONtemporarilyoff,use: ONMENUBUTTONclicks,button,eventGOSUBdummy TheProcedureDummyshouldbeempty.Usethesamemethodtoswitchother ONMENUcommandstemporarilyoff. üONMENUIBOXÇ YoucandefinetwoindependentrectangleswithONMENUIBOXand/orONMENU OBOX,either: -oneIBOXandoneOBOX -twoIBOXes -twoOBOXes üë22.PULLDOWNMENU Ç üOPENW0Ç Evenifyoudon'tneedawindow,youcould'OPENW0'ifyouusea pulldownmenu.Thetopline(y-coordinates0to18inHighresolution, that'swhereyourmenuis)isnowprotectedagainstaccidentaldrawing. After'OPENW0'19isalwaysaddedtothey-coordinate,sowith'PLOT0,0' thepointisactuallydrawnat(0,19). üDesk-submenuÇ TheêfirstÇsubmenuinapulldownmenushouldbetheDesk-submenu('Desk'), usuallywiththefollowinglay-out: Info ------------ Accessory1 Accessory2 (...) IftheuserchoosestheInfo-item,youshouldshowsomeinformationabout theprogram.TheAEStakescareoftheaccessory-items,yousimplyuse '1,2,3,4,5,6'inthecorrespondingDATA-line.Ifyouuse'-,-,-,-,-,-'the userwon'tbeabletochooseanaccessoryfromyourprogram,butall loadedaccessoriesstilloccupymemory. üFile-submenuÇ Mostpulldown-menu'scontainaFile-submenu('File')astheêsecondÇ submenu.Thefollowinglay-outismoreorlessstandard: Newfile ^N Openfile... ^O ----------------- Close ^C Save ^S Saveas... ^M Abort ^A ----------------- Quit ^Q With'...'youannouncethatfurtherinputfromtheuserwillbe requested.Ifatallpossible,youshouldofferoptionalkeyboard- alternativesfortheexperienceduser.With'^N'youremindtheuserof the<Control><N>alternative.ThecharacterwithASCII-code7isusedas thesymbolfor<Alternate>.Bygeneralagreement,theQuit-choicealways isthelastitemoftheFile-submenu. Bytheway,neverleavethelast(rightmost)submenuwithoutoptions,e.g. duringdevelopmentofaprogram.Theremustbeatleastoneoptioninthe lastsubmenu,orit'sreset-timeagain. üë23.WINDOWS ê üGFA-windowsÇ You'llnoticethatthischapterisrathershort.Thisreflectsmy reservationsabouttheuseofwindows.Iknowveryfewprogramsthatuse windowssensibly.FortheseprogramsGEM-windowsindeedareablessing. Butmostprogramsarebetteroffwithoutwindows.GEMjustslowsthe screen-outputdown.CoveryourTOS-screenwithwindowsonlyifyoureally needthem. GFA-Basichasfour"easy"windowsfornottoocomplicatedjobs.Drawan imaginarycrossonthescreen.Theintersectionofthetwolinesis determinedbythecoordinatesin'OPENWn,x,y'.Ifyoushowmorethanone windowonthescreen,youshouldrealizethatresizingonewindowauto- maticallychangesthesizeoftheotherthreewindowsaswell(remember thecross?).UsetheAESwindow-commandsifyouneedindependentwindows. ThefourGFA-windowsreservethetoplineforapulldownmenu.Ifyouuse yourownAES-windows,youshouldprotectthetoplineyourself,e.g.with 'OPENW0'. Astandard-methodfortheuseofGFA-windowslookslikethis: TITLEW#1,"title" !automaticallycentered INFOW#1,"information" !leftjustified OPENW1 !oruseFULLW#1 CLEARW1 (...) CLOSEW1 CLOSEW0 Idon'tknowhowtouse'#'properly.Theeditordoesnotaccept'#'in 'OPEN#1',youhavetouse'OPENW1'.IfyouuseFULLWinsteadofOPENW, youhavetouse'FULLW#1'.Inthiscasethe'#'hastobeused,orthe commanddoesn'tworkatall!TheGFA-editoralwaysinsertsa'#'after TITLEWandINFOW,evenifyoudidn'ttypeone.Whatthe#isgoingon? ü CLOSEWÇ Ifyouhaveopenedawindowinyourprogram,alwaysuse'CLOSEW0'before returningtotheeditor.Ifyoudon't,youcan'tworknormallyinDirect Mode.Ifyoudidforget,youcantype'CLOSEW0'inDirectModeand everythingworksfineagain. IfyouusetheAESwindow-commands,alwayscallWIND_CLOSE(handle)before WIND_DELETE(handle). üTITLEWÇ ü ÇYoucanclearatitlewith: TITLEW#n,"" Don'tuse""insteadof"",oryouwon'tbeabletomovethewindow afterwards! üCLEARWÇ After'CLEARW#n'allvisibleareasofthewindowarecleared,êwithoutÇ activatingthewindow.GFAusesWIND_UPDATEandWIND_GETforthiscommand. 'CLEARWn'bothclearsêandÇactivatesthewindow. üë24.AES-LIBRARY Ç üALERTÇ IfyouneedanemptylineinanAlert-box,use: ALERT,3,"...||...",1,"...",k Notethespacebetweenthetwoverticalrules. GFA-Basicallowsê4Çlinesof30characters(High/Mediumrez)ifyouuse ALERT,butwithFORM_ALERTyoucanuseê5Çlines.Inbothcasesyoucanuse notmorethan3buttons,eachatmost8characters(High/Mediumrez)wide: m$="line1|line2|line3|line4" ALERT3,m$,1,"OK",k ' m$="[3][line1|line2|line3|line4|line5][OK]" k=FORM_ALERT(1,m$) InLowresolutionyoucanuseonlyhalfthenumberofcharactersyouuse inHigh/Mediumresolution. Ifsomecharactersarenotvisibleinabutton,trybroadeningtheAlert- boxbyaddingspacestothewidesttext-line. Ifyouhavepressedtheleftmouse-buttonontheveryspotwhereanAlert- buttonisabouttoappear,somethinggoeswrong.GEMappearstoremember yourlastmouse-click,anderroneouslyassumesyoupressedthebutton êafterÇtheAlert-boxappeared.GEMonlyselectsthebuttonifthemouse- clickoccurredintheexactareaoftheAlert-button.Toavoidthis problemyoushouldmakesuretheuserhasreleasedthemouse-buttonbefore youcalltheAlert-box: REPEAT UNTILMOUSEK=0 !waituntilmousereleased Bytheway,theAESusesan8Kbuffertosavethepartofthescreenwhere theAlert-boxappears.Dittoforamenu. üSHEL_GETandSHEL_PUTÇ GFA-Basicisrunfroma'Shell-Program',usuallytheDesktop.Inthatcase thefileDESKTOP.INFcanbefoundintheEnvironment-Buffer.Youcan examinethisfilebytransferringittoastring: d$=STRING$(1024,0) r%=SHEL_GET(1024,d$) PRINTingthisstringismucheasierthanusingadisk-editortoexamine DESKTOP.INF. ÇAfterchangingthestring,youcouldputitbackinthebufferwith: r%=SHEL_PUT(1024,d$) Thiswayyoucouldchangethelay-outofthedesktop.Ifyouchangethe string,youshouldknowthattheDesktoprecognizestheendofDESKTOP.INF bythebyte&H1A.Sodon'tforgettoputCHR$(26)attheend.Ifyouwant tosavethenewbuffer,try: OPEN"O",#1,"\DESKTOP.INF" PRINT#1,LEFT$(d$,INSTR(d$,CHR$(26))) CLOSE#1 IsthatallthereistotellabouttheAES-library?Certainlynot,soat thispointyouwillprobablybebitterlydisappointed.IavoidtheAES- LibrarywheneverIcan.Anyway,thisisasubjectthatisthoroughly coveredinmostbooksaboutGFA-Basic3.0.Everyoneisentitledtohisown opinionabouttheusefulnessofRSC-filesandotherexoticsubjects. Betterstill,writethischapteryourself.Andthesametoyoutoo! üë25.GFAXPERT-FILES Ç Takeyourtimetoreadthischaptercarefully,beforeusingtheGFAXPERT- Proceduresorprograms.Theparagraph'STANxxxx.LST'isessentialreading. Don'tforgettoreadthe'ásmallprintÇ'inthelastparagraph. üGFAXPERT.DOCÇ You'rereadingit. üGFAXPERT.LIBÇ Thisfolder(inGFAXPRT2.ARCfordownloaders)containsalargecollection ofProceduresinseveralLST-files.EachLST-filecontainsoneormore foldedProcedures.MostProceduresarealsolistedinthistext,orareat leastmentioned.IsuggestyouLlistalltheLST-fileswithunfolded Proceduresforeasyreference.YoucouldalsoLlistallLST-filesagain withfoldedProcedures,soyouwillbeabletolocateaProcedurequickly. Alwaysreadthecomment-lines('***)inaProcedurebeforeusingit.You willfindthereifotherProceduresareused,orStandardGlobals(see paragraph'STANxxxx.LST').SometimesaProcedurereturnsaglobal variable.MostvariablesaredeclaredasLOCAL.Anddoreadtherelevant chapterofthistextbeforeusingaProcedure. GFAhasreleasedalibraryofgraphics-andsound-routines.Iamcurious aboutthequalityoftheseroutines,butIcertainlydonotintendtopay DM148.-forthelibrary.Myadvicewouldbetousethelibrary GFAXPERT.LIBandpayDM148.-tome. üINLINEÇ TheINLINE-folder(inGFAXPRT2.ARCfordownloaders)containsINLINE-files thatyouwillhavetoloadafterMergingcertainProcedures.Thisis clearlyindicatedinsuchProcedures. üSTANxxxx.LSTÇ Beforewritingaprogram,Idecideinwhichresolutiontheprogramwill run.ThenIMergethecorrespondingSTANxxx.LST-file(inthefolder GFAXPERT.LIB)andusethatasthestandardframeworkformyprogram: STANHIGH.LST -Highresolution STANMED.LST -Mediumresolution STANLOW.LST -Lowresolution STANHIME.LST -HighorMediumresolution STANALL.LST -allresolutions Afterdeletingthefirsttwolinesandenteringthenameoftheprogram (e.g.TEST.GFA),ISavetheprogramasAAPROG.GFAintheProcedure- library.InthisfolderIhaveafewLST-filesreadyforeasyMergingof ÇProceduresintotheprogram(AABLOCK1.LST,AABLOCK2.LST,etc.). Beforeyoucontinue,youshouldLlistthefiveSTANxxxx.LST-files.Merge STANHIGH.LST,unfoldallProcedures,thenLlist.Intheotherfilesyou couldrestrictunfoldingtotheProcedureInitio(andperhapsthe Proceduresxxx.modeandStandard.xxx.colors).I'llwaituntilyouhavethe listingsoftheSTAN-filesinfrontofyou... Right,firstI'lldiscussSTANHIGH.LSTthoroughly.LaterI'llpointout someimportantfeaturesintheotherSTAN-files.Youwillnotbecomean expertinstructuredprogrammingimmediately,butusingtheSTAN-files shouldhelp. (1)Thefirstline('STANHIGH.LST')istheretoremindyouhowto'Save,A' thisfileafteryouhavechangedit.Deleteitifyouaregoingtodevelop anewprogram. (2)Enterthenameofyournewprogram(e.g.TEST.GFA)andimmediately savetheprogramasAAPROG.GFAintheProcedure-library. (3)Word-variablesaredefinedasthedefault. (4)TheProcedureInitioiscalled.InthisProcedurethecurrent resolutionischecked,andafterthat,afewimportantglobalvariables aredefined(StandardGlobals).ThefollowingStandardGlobalsaredefined (readthecommentsinthelistingformoreinformation): high.res! scrn.col.max return$ scrn.lin.max esc$ default.path$ help$ white undo$ physbase% black logbase% interpreter$ on! run.only$ scrn.x.max off! start.gfa$ scrn.y.max start.prg$ bel$ char.width char.height Also,theStandardArraycolor.index()iscreated,althoughyou'llonly needitforafewProcedures(e.g.Initio.sprite1). (5)TheProcedureTitle.screenisnotactivatedyet.You'llprobablywant tochangethatProcedure. (6)Anormal<Break>shouldbepossiblewhiledevelopingaprogram.Inthe finishedprogramyoucouldactivatetheProcedureBreak,ordeleteit.Be verycarefulwith<Break>iftheprogramusesRESERVEorhaschangedthe addressofthephysical/logicalscreen. (7)ThemainprogramusuallyisnotmuchmorethanalistofProcedure- calls,e.g.: @start.game @play.game @score Ç(8)TrytoleavetheprogrambycallingtheProcedureExit.During developmentit'smoreconvenienttoleavewith'EDIT'. (9)TwoStandardFunctionsaredefined:Center$forcenteringtextand Rev$forPRINTingreverse.ThelastfunctionusesVT52-codes,souseiton theTOS-screenonly. (10)TheStandardProcedureHigh.mode(calledfromInitio)checksthe currentresolutionandabortswithanappropriatemessageiftheprogram isruninthewrongresolution. (11)TheStandardProcedureGet.path(calledfromInitio)returnsthe currentpath.Usingtheinterpreter,GEMDOSreturnsthepathofthe interpreter(e.g.'A:\'),ênotÇoftherunningprogram!That'swhyIuse CHDRIVE+CHDIRintheshell-programs.InthatcasetheStandardGlobal default.path$doescontainthepathoftherunningGFA-program.Ifyou developtheprogram,youshoulduseCHDRIVE/CHDIRinDirectModeif necessary.Iamnothappywiththismethod,butIknownoothersolution forGFA-programs.IfIdon'tusethismethod,Ialwaysdefinethepathin theInitiation-part,e.g.: path$="A:\GAMES\" !wherearethedata-files? NowanotherGFA-useronlyhastochangethepathandtheprogramcanfind thenecessaryfiles.ForownersoftheRun-Onlyinterpreteryoushould describetheproperconfigurationinaREAD.ME-file.WithcompiledGFA- programsthereisnoproblem,becauseGEMDOSwillreturnthepathofthe runningprogram. (12)Iliketobegineveryprogramwithatitle-screen.Changethe StandardProcedureTitle.screen,ordeleteitifyoudon'tliketitle- screensinyourprograms. (13)TheStandardProcedureReturnisusedbyTitle.screen. (14)TheStandardProcedureBreakcanbedeletedifyoudon'tneedit. Don'tuse'ONBREAKCONT'inyourprogram,unlessyouhaveaverygood reasontodoso.NotethatIhavemadeitpossibletouse<Break>the normalwayiftheuserchooses<CONT>whilepressingthe<Break>- combination. (15)TheStandardProcedureExitshouldalwaysbeused.ThisProcedure triestogobacktooneoftheshell-programs.Ifthat'simpossible,the Proceduredecidestoendwith'EDIT'or'SYSTEM'.Isitpossibletotest inaprogramifitisrunbytheinterpreterorifitisacompiled program?Iftheanswerisyes,thisProcedurecouldbeimproved. (16)OtherProcedurescanbeinsertedafter'***Procedures***'.Merge ProceduresfromthelibraryGFAXPERT.LIB(oryourownlibrary)here.Iuse thefollowingmethod: -New,somemoryisclear -MergerelevantLST-filefromlibrary -choose(folded)ProcedureandWriteasblocktoAABLOCKx.LST -repeatpreviousstepsforotherProcedure(s) -LoadAAPROG.GFA -MergeAABLOCKx.LSTatappropriateposition(s) Ç -Saveprogram(press<Return>inFileselector) Ofcourse,you'llhavetowriteafewProceduresfromscratch.Beforeyou knowit,you'llhavereachedTheEnd.It'ssoeasytowriteaprogramin GFA-Basic3.0,thatIactuallyenjoyprogramming. (17)Debuggingisperhapslessfunthanprogramming.MergetheProcedure Debugtemporarilyinyourprogramifyouneedsomehelp.Anddosaveyour programregularly!FallbacktotheprogramAAPROG.BAKifyourlatest improvementswerefatal.Ifyouarecompletelysatisfied,savetheprogram underitspropername(TEST.GFA).Alsosaveaback-uponanotherdisk, justincasesomethingterribleshouldhappentoyouroriginalprogram. (18)InSTANALL.LSTyou'llnoticeintheProcedureInitiothatIalways startwiththedefaultpalette(ProceduresStandard.med.colorsand Standard.low.colors).NewStandardGlobalsinSTANALL.LSTare: red med.res! green low.res! TheStandardArraycolor.index()isveryimportantinMediumorLow resolution. (19)InSTANHIME.LST(myfavourite)theonlyimportantdifferenceisthe ProcedureHigh.med.mode,wherethecurrentresolutionischecked. (20)InSTANLOW.LSTall16default-coloursarenowdefinedasStandard Globals : white blue grey l.purple black d.blue l.black d.purple red brown l.blue d.yellow green d.green bluegreen l.yellow WithtwonewStandardFunctionsyoucanchangethecolourofPRINTedtext (Ink$)orthecolourofthebackground(Paper$).Bothfunctionsworkon theTOS-screenonly.ThecurrentresolutionischeckedintheProcedure Low.mode. (21)NothingnewinSTANMED.LST,excepttheProcedureMed.modetocheck theresolution. Perhapsyoufindallthistalkabouta"standard"program-structurevery boring.Ifyouwriteaprogram,whycareaboutstructure?Becauseit's mucheasiertochangeastructuredprogram,especiallyifyoudidn'twrite theprogramyourself.Changeanunstructuredprogram,andyou'regoingto besurprisedbysome(hidden)unwantedside-effects.Makeotherusers happy,spreadyourbeautifulprogramsonlyiftheyarestructuredandwell commented.Dospreadthe(listable)êsourceÇofyourprogram,sootherusers canlearnfromyou.Anddon'tbeinsultedifothersimproveyourprogram. Icertainlywillnotbeinsultedifyousendmeyourownthoughtsabout structuredprogramminginGFA-Basic3.0. üSTART Ç IntheSTART-folder(inGFAXPRT2.ARCfordownloaders)youwillfindthe followingprograms: START.GFA -HighorMediumresolution STARTLOW.GFA -Lowresolution GFASTART.GFA -allresolutions IusetwodifferentdisksformyGFA-programs.Oneforprogramsthatrun inHighand/orMediumresolution(savethedesktopinMediumresolution!). AndoneforprogramsthatruninLowresolution. START.GFAandSTARTLOW.GFAareusedasakindofshelltoruntheGFA- programsonthesedisks.Notatrueshell,butit"feels"likeallGFA- programsarerunfromSTART.GFAandSTARTLOW.GFA.IstartaGFA-session bydouble-clickingtheshell-programonthedesktop('GFA'hasbeen installedasapplicationforGFABASIC.PRG). AllmyprogramstrytoCHAINoneoftheshell-programswhentheuserexits theprogram.Twoimportantremarksifyoudecidetousetheseshell- programs: -verticalfrequencyisswitchedto60HzinMediumorLowresolu⑨ tion;notagoodideaifyouuseaTVthroughamodulator! -WriteVerifyTestisswitchedoff Ifyoulike,youcanactivatethecheckforaboot-virusintheshell- programs.Theshell-programandGFABASIC.PRG(orGFABASRO.PRG)shouldbe inthemaindirectory! GFASTART.PRGisusedinthesamewaywithcompiledGFA-programs.Allmy compiledGFA-programstrytoCHAINthisshell-programwhenexiting.The sourceforthisprogramisGFASTART.GFA.CompilethisasGFASTART.PRGand putitinthemaindirectory. AllthreeSTART-programscontainplentycomments,soyoushouldbeableto understandhowtheprogramsworkbystudyingthelistings.Theshell- programscertainlycanbeimproved,I'mnotyetsatisfiedwiththecurrent programs. ísmallprintÇ Readthisparagraphcarefully,beforeusingtheGFAXPERT-files.Thefiles areênotÇPublicDomain! YouarefreetouseandchangeallGFAXPERT-files,butonlyforpersonal use.Certainlynotforcommercialuse. YouareinvitedtocopytheoriginalGFAXPERT-diskortheGFAXPRTx.ARC- filesandgivethesetoyourfriends.Butyouarenotallowedtochange anythingonthediskorinthefiles.Ifyoufeeltheurgetochange something,don'tdoit,butwritetome(readthechapter'EPILOGUE'). Youarenotallowedtosell(filesfrom)theGFAXPERT-diskoroneofthe GFAXPRTx.ARC-files.ThediskGFAXPERTmayonlybesoldbyso-calledPublic DomainClubsiftheyhavemywrittenpermissiontodoso.BBS'sarefree tomaketheoriginalGFAXPRTx.ARC-filesavailablefordownloading. AnypartfromthetextGFAXPERT.DOCortheProcedure-libraryGFAXPERT.LIB maybequotedinnewslettersormagazines,ifaccompaniedbyareference like: fromGFAXPERT(2nded.)byHanKempen Icannotbeheldresponsibleforanydamagethatmayresultfromrunninga GFAXPERT-program,usingaProcedurefromthelibraryGFAXPERT.LIB,or usinginformationfromthistext. (c)HanKempen,3July1990 üëEPILOGUE Ç Well,that'sallfolks.I'mquitecertaintherearestillafewbugstobe foundinthistextandintheProcedure-LibraryGFAXPERT.LIB.Bynowyou shouldhavebecomeanexpertinGFA-Basic3.0,soyouwillbeabletospot thembugsimmediately.Pleaseletmeknowifyoufindone. PerhapsyoustillhavesomeunansweredquestionsaboutGFA-Basic.Oran answertooneofmyownquestionsinthistext.OrsomeneatProcedures. Orabrilliantprogram.Iwouldappreciateitverymuchifyouwouldsend yourletterand/ordiskto: HanKempen Rubensstraat12 7741ARCoevorden theNetherlands Doshareyourideas,Proceduresandprogramswithothers,startingwith me.ConsideritasmallpaymentfortheGFAXPERT-files.Thanks. WishingyoumanyhappyhourswithGFA-Basic3.0, HanKempen üëINDEX Ç (#) = Procedure or Function \ ..................................... 29 " ..................................... 41 1st Word Plus ......................... 62 40-folder limit ....................... 66 abbreviated commands .................. 12 accessory ............................. 25,101 ACHAR ................................. 96 ACLIP ................................. 99 After$ (#) ............................ 32 AFTER ................................. 82 ALERT ................................. 106 application ........................... 9 ARECT ................................. 88 ASCII-code ............................ 33,34,36,37 Ascii.qsort (#) ....................... 27 ATEXT ................................. 96 attribute ............................. 53 AUTO .................................. 9 BCHG .................................. 30 BCLR .................................. 29 Before$ (#) ........................... 32 Bezier-curve .......................... 92 BGET .................................. 62 BIOS 4 (Rwabs) ....................... 59 BIOS 7 (Getbpb) ...................... 56,60 BIOS 9 (Mediach) ..................... 60 BIOS 10 (Drvmap) ...................... 51 BIOS 11 (Kbshift) ..................... 36 bit-mask .............................. 29 Blitter (#) ........................... 99 BLOAD ................................. 61 Block.dimmer (#) ...................... 91 Boolean ............................... 17 boot .................................. 9,61 BPB ................................... 56 BPUT .................................. 62 break ................................. 10 Break (#) ............................. 110 BSAVE ................................. 61 BSET .................................. 30,79 bug (GFA) ............................. 12,20,24,25,31,32,36,42,80,83, 84,92,96,97,101 bug (TOS) ............................. 25,35,55,56,63,64,66,70,95,102 Çcalculations .......................... 79 Caps (#) .............................. 39 CapsLock .............................. 38 CARD .................................. 31 CHAIN ................................. 83 Change.font (#) ....................... 44 Change.midi.buffer (#) ................ 67 Change.palette (#) .................... 85 characters ............................ 16,34 CHDIR ................................. 51,110 CLEAR ................................. 19 CLEARW ................................ 105 CLIP .................................. 92 CLOSEW ................................ 104 cluster ............................... 58 Coldstart (#) ......................... 9 color ................................. 40 Color.cycle (#) ....................... 86 correlation ........................... 31 COSQ .................................. 30 CURVE ................................. 92 Cut and Paste ......................... 13 Cycle.once (#) ........................ 87 DATE$ ................................. 22 Day.of.week (#) ....................... 22 Debug (#) ............................. 19,111 DEFFILL ............................... 87 DEFLINE ............................... 89 DEFLIST ............................... 15 DEFMARK ............................... 87 DEFMOUSE .............................. 72 DEFTEXT ............................... 89 DEFWRD ................................ 17 Degas-Pictures ........................ 97 Degas.screendump (#) .................. 46 DELAY ................................. 83 Desk-submenu .......................... 103 DESKTOP.INF ........................... 106 DFREE ................................. 56,58 Digital$ (#) .......................... 93 DIM ................................... 19 Dim.colors (#) ........................ 86 DIR$() ................................ 50 DIR ................................... 51 Direct mode ........................... 15 disk format ........................... 55 disk-swap ............................. 60 Do.sound (#) .......................... 76 DRAW .................................. 91 DTA-buffer ............................ 52 DUMP .................................. 19 ÇEditor ................................ 71 EQV ................................... 31 ERASE ................................. 19,24 ERROR ................................. 82 EVERY ................................. 82 EXEC .................................. 24,83 EXIST ................................. 54 Exit (#) .............................. 110 fade-over ............................. 99 Fastprint (#) ......................... 41 FAT ................................... 58 FDC ................................... 55 FGETDTA ............................... 52 File Allocation Table ................. 58 File.copy (#) ......................... 55 File-submenu .......................... 103 FILES ................................. 51 FILESELECT ............................ 63 Fileselect (#) ........................ 64 Fileselector .......................... 63,71 floating point ........................ 18 Floppy Write Test ..................... 50 Folded Procedures ..................... 13 font .................................. 43,89 Font.8x16 (#) ......................... 43 Font.8x8 (#) .......................... 43 FONTKIT ............................... 44 FOR ... NEXT .......................... 79 Force.mediach (#) ..................... 60 FORM_ALERT ............................ 106 FSETDTA ............................... 52 FSFIRST ............................... 52 FSNEXT ................................ 52 Full.fill (#) ......................... 88 FULLW ................................. 104 FUNCTION .............................. 19 GEMDOS 17 (Cprnos) .................... 45 GEMDOS 25 (Dgetdrv) ................... 50 GEMDOS 48 (Sversion) .................. 10 GEMDOS 54 (Dfree) ..................... 56 GEMDOS 67 (Fattrb) .................... 53 GET ................................... 96 Get.path (#) .......................... 110 GFA-windows ........................... 104 GFAXPERT.DOC .......................... 7,108 GFAXPERT.LIB .......................... 7,108 GOSUB ................................. 82 GOTO .................................. 82 GRAPHMODE ............................. 90 ÇHARDCOPY .............................. 45 harddisk .............................. 51,55,58,59 High.screendump.epson (#) ............. 45 High.screendump.star24 (#) ............ 45 HLINE ................................. 96 IBOX .................................. 102 IF ... ENDIF .......................... 78 INFOW ................................. 194 Initio (#) ............................ 109 Initio.fill1 (#) ...................... 88 Initio.high.fill1 (#) ................. 87 Initio.keyget (#) ..................... 36 Initio.logical.screen (#) ............. 42 Initio.mouse1 (#) ..................... 72 Initio.printer (#) .................... 47 Initio.sound (#) ...................... 75 Initio.sprite1 (#) .................... 93 Initio.text.array (#) ................. 62 Ink$ (#) .............................. 40 INKEY$ ................................ 33 INLINE ................................ 24,108 INP ................................... 62,67,70 INPAUX$ ............................... 70 INPMID$ ............................... 67 INPUT ................................. 34,62 INPUT$ ................................ 35 Insert-mode ........................... 15 INSTR ................................. 32 INT{} ................................. 23 integer ............................... 18 Intel.word (#) ........................ 31 interleave ............................ 57 Invert.block (#) ...................... 91 joystick .............................. 74 Key.click (#) ......................... 38 Key.repeat (#) ........................ 39 keyboard .............................. 37 keyboard-buffer ....................... 33 Keyboard.version (#) .................. 37 KEYDEF ................................ 37 KEYGET ................................ 35 KEYLOOK ............................... 36 KEYPAD ................................ 37 KEYPRESS .............................. 37 KEYTEST ............................... 35 KILL .................................. 54 ÇLine-A ................................ 95 LINE INPUT ............................ 35,62 Llist ................................. 14 Load .................................. 13 LOCATE ................................ 41 LOF ................................... 54 LOG ................................... 30 logical screen ........................ 42 loops ................................. 80,119 LSET .................................. 32 Make.high.fill (#) .................... 88 Make.mouse (#) ........................ 73 Make.palette.string (#) ............... 85 Make.sprite (#) ....................... 94 MALLOC ................................ 25 MAX ................................... 31,78 Max.array (#) ......................... 31 memory ................................ 23,24,25 MENU() ................................ 101 Midi-buffer ........................... 67 Midi-commands ......................... 67 Midi.monitor (#) ...................... 68 MIN ................................... 78 MOD ................................... 29 monitor ............................... 10 MOUSE ................................. 71 MS-DOS disk ........................... 58 NAME .................................. 54 Neochrome-Pictures .................... 98 New.med.colors (#) .................... 85 Normal.font (#) ....................... 44 NOT ................................... 81 OBOX .................................. 102 ON BREAK GOSUB ........................ 82 ON MENU BUTTON ........................ 101 ON MENU IBOX .......................... 102 OPENW ................................. 104 OPENW 0 ............................... 103 Operating System ...................... 10 OUT ................................... 40,62 Overwrite-mode ........................ 15 palette ............................... 84,111 Palette.box (#) ....................... 86 Paper$ (#) ............................ 40 Parse.filename (#) .................... 65 parser ................................ 32 PCIRCLE ............................... 92 physical screen ....................... 42 ÇPlay.midi (#) ......................... 68 PLOT .................................. 91 point-commands ........................ 14 PRED .................................. 29 PRINT ................................. 40 Print.stopwatch (#) ................... 21 PRINT TAB ............................. 42 printer-commands ...................... 47 printer-driver ........................ 14 printer-parameters .................... 45 Printer.ready (#) ..................... 45 PUT ................................... 96 QSORT ................................. 26 RAM ................................... 23 RAM-disk .............................. 50 READ .................................. 20 RECALL ................................ 62 Record.midi (#) ....................... 67 RESERVE ............................... 23 reset ................................. 9,50 RESTORE ............................... 20 Restore.palette (#) ................... 85 Restore.physical.screen (#) ........... 43 Return (#) ............................ 110 reverse ............................... 41,84 Rgb.value (#) ......................... 85 right justification ................... 32 RS232-buffer .......................... 70 RSET .................................. 32 Rubber.line (#) ....................... 90 samples ............................... 76 Save .................................. 14 Save,A ................................ 14 Save.palette (#) ...................... 85 scan-code ............................. 33,36,37,38 scrap-library ......................... 83 Screen.dimmer (#) ..................... 91 Screendump (#) ........................ 45 Scroll.text.up (#) .................... 99 Scroll.up (#) ......................... 98 sectors ............................... 59 SELECT ................................ 78 serial number ......................... 57 SETCOLOR .............................. 84 SETMOUSE .............................. 71 SHEL_GET .............................. 106 SHEL_PUT .............................. 106 shell-program ......................... 112 SHL ................................... 79 Show.degas (#) ........................ 97 Show.text.page (#) .................... 63 ÇShuffle (#) ........................... 20 SINQ .................................. 30 SOUND ................................. 75 Soundmachine .......................... 77 special characters .................... 16 speech ................................ 77 SPRITE ................................ 93 SSORT ................................. 26 Standard .............................. 7 Standard Array ........................ 109,111 Standard Functions .................... 110,111 Standard Globals ...................... 109,111 STANxxxx.LST .......................... 108 START ................................. 112 start-up .............................. 9 Step Rate ............................. 50 STICK ................................. 74 Stopwatch (#) ......................... 21 STORE ................................. 62 STRIG ................................. 74 String.index.qsort (#) ................ 28 SUCC .................................. 29 supervisor mode ....................... 23 SWAP .................................. 20,31 Swap.screen (#) ....................... 43 syntax ................................ 12 system-font ........................... 43,89 Tab ................................... 13,41 TAB ................................... 42 TEXT .................................. 92 text-array ............................ 62 Text.at (#) ........................... 92 TIME$ ................................. 21 Time (#) .............................. 21 TIMER ................................. 21 Title.screen (#) ...................... 110 TITLEW ................................ 104,105 TOS ................................... 10 TOS-screen ............................ 40 TOUCH ................................. 54 twisted format ........................ 57 TYPE .................................. 20 VAR ................................... 18 variable type ......................... 17 VDISYS 38 (vqt_attributes) ............ 89 VQT_EXTENT ............................ 95 VSETCOLOR ............................. 84 VSYNC ................................. 98 VT52 .................................. 40 ÇWarmstart (#) ......................... 9 WAVE .................................. 75 WIND_CLOSE ............................ 104 word .................................. 17,31 WORD .................................. 23,59 write-protect ......................... 60 XBIOS 0 (Initmous) ................... 71 XBIOS 5 (Setscreen) .................. 42 XBIOS 6 (Setpalette) ................. 85,97 XBIOS 7 (Setcolor) ................... 84 XBIOS 8 (Floprd) ..................... 60 XBIOS 10 (Flopfmt) .................... 56 XBIOS 15 (Rsconf) ..................... 70 XBIOS 16 (Keytbl) ..................... 37,38 XBIOS 18 (Protobt) .................... 57 XBIOS 19 (Flopver) .................... 56 XBIOS 32 (Dosound) .................... 75 XBIOS 33 (Setprt) ..................... 45 XBIOS 36 (Prtblk) ..................... 47 XBIOS 64 (Blitmode) ................... 99