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######## ################## ###### ###### ##### ##### #### #### ## ##### #### #### #### #### #### ##### ##### ## ## #### ## ## ## ### ## #### ## ## ## ##### ######## ## ## ## ##### ## ## ## ## ## ##### ## ## ######## ## ## ## ### ## ## #### ## ## ##### #### #### #### #### ##### #### #### #### #### #### ###### ##### ## ###### ###### ╓OLUME 1, ╔SSUE #4 ################## ╧CTOBER 5, 1992 ######## ----------------------------------------------------------------------------- ┼DITOR'S ╬OTES: BY ├RAIG ╘AYLOR (DUCK@PEMBVAX1.PEMBROKE.EDU) ═Y APOLOGIES ABOUT THIS ISSUE BEING POSTED LATER THAN WAS MENTIONED IN A PREVIEW POST ON COMP.SYS.CBM NEWSGROUP. ─UE TO SOME PROBLEMS WITH CODING, SCHOOL AND ═URPHY'S LAW THE ISSUE HAD TO BE DELAYED UNTIL NOW. ╔ HAVE ASKED THE SYSTEM ADMIN'S AT MY SITE CONCERNING A MAIL-SERVER BUT THEY SAID THEY DID NOT HAVE ENOUGH MAN-POWER (GO FIGURE) TO GET SOMEBODY TO RUN IT. ╔ WILL BE IMPLEMENTING A MAIL-SERVER SYSTEM IN MY ACCOUNT IN THE NEAR FUTURE FOR RETRIEVAL OF PROGRAMS AND BACK-ISSUES. ╔'LL POST DESCRIPTIONS OF HOW TO USE IT IT THE NEXT ISSUE OF ├= ╚ACKING AS WELL AS ON THE NEWSGROUP COMP.SYS.CBM WHEN ╔ FINISH WRITING IT. ╔N THIS ISSUE OF ├= ╚ACKING WE ALSO START ON AN AMBITIOUS TASK: ─EVELOPING A GAME FOR BOTH THE ├128 AND ├64 MODES THAT INCLUDES ALL OF THE FEATURES FOUND IN COMMERCIAL GAMES. ╘AKE A LOOK IN THE ╠EARNING ═╠ ├OLUMN FOR MORE INFORMATION. ┴LSO, ╘HE ARTICLE CONCERNING THE 1351 MOUSE HAS _AGAIN_ BEEN DELAYED DUE TO TIME CONSTRAINTS. ╥EST ASSURED THAT IT WILL BE IN THE NEXT ISSUE OF ├= ╚ACKING. ╔F YOU ARE INTERESTED IN HELPING WRITE FOR ├= ╚ACKING PLEASE FEEL FREE TO MAIL DUCK@PEMBVAX1.PEMBROKE.EDU (OR DUCK@HANDY.PEMBROKE.EDU). ╫E'RE ALWAYS LOOKING FOR NEW AUTHORS ON ALMOST ANY SUBJECT, SOFTWARE OR HARDWARE. ================================================================================ ┴LSO NOTE THAT THIS ISSUE AND PRIOR ONES ARE AVAILABLE VIA ANONYMOUS FTP FROM CCOSUN.CALTECH.EDU UNDER PUB/RKNOP/╚┴├╦╔╬╟.═┴╟. ================================================================================ ╬╧╘╔├┼: ╨ERMISSION IS GRANTED TO RE-DISTRIBUTE THIS "NET-MAGAZINE", IN WHOLE, FREELY FOR NON-PROFIT USE. ╚OWEVER, PLEASE CONTACT INDIVIDUAL AUTHORS FOR PERMISSION TO PUBLISH OR RE-DISTRIBUTE ARTICLES SEPERATELY. *** ┴╒╘╚╧╥╙ ╠╔╙╘┼─ ┬┼╠╧╫ ╥┼╘┴╔╬ ┴╠╠ ╥╔╟╚╘╙ ╘╧ ╘╚┼╔╥ ┴╥╘╔├╠┼╙ *** ================================================================================ ╔N THIS ISSUE: ╠EARNING ═╠ - ╨ART 4 ╔N THE NEXT ISSUE WE'LL EMBARK ON A PROJECT OF MAKING A SPACE INVADERS STYLE GAME FOR THE ├=64/128 FROM SCRATCH USING CUSTOM CHARACTERS, INTERRUPT-DRIVEN MUSIC, ANIMATION, USING THE JOYSTICK, MOUSE OR KEYBOARD. ╘HE ├64 AND ├128 VERSIONS WILL BE DEVELOPED CON-CURRENTLY, EACH PROGRAM TAKING ADVANTAGE OF THE MACHINE'S CAPABILITIES. ╘HIS IS THE FIRST IN A SERIES - WRITTEN BY ├RAIG ╘AYLOR. ╘HE ─EMO ├ORNER: ╞╠╔ - MORE COLOR TO THE SCREEN ┴LL OF US HAVE HEARD COMPLAINTS ABOUT THE COLOR CONSTRAINTS ON ├64. ╞╠╔ PICTURE CAN HAVE ALL OF THE 16 COLORS IN ONE CHARACTER POSITION. ╫HAT THEN IS THIS ╞╠╔ AND HOW IT IS DONE ? ╫RITTEN BY ╨ASI '┴LBERT' ╧JALA. ╥╙-232 ├ONVERTER ╘HIS ARTICLE DETAILS PLAN FOR A ╒SER PORT ╘╧ ╥╙232 CONNECTOR USING JUST ╧╬┼ ╔├ AND 4 CAPACITORS. ╘HE CIRCUIT IS INCLUDED, AND SUGGESTIONS ON ALTERNATIVE CHIPS AND PARTS ARE EXAMINED. ╫RITTEN BY ╫ARREN ╘USTIN ╔NTRODUCTION TO THE ╓╔├-╔╔ ╘HIS ARTICLE EXAMINES THE ╓╔├-╔╔ CHIP IN DETAIL AND PROVIDES AN EXPLANATION OF THE VARIOUS REGISTERS ASSOCIATED WITH THE CHIP. ╫RITTEN BY ╨ASI '┴LBERT' ╧JALA. ╠╔╘╘╠┼ ╥┼─ ╥┼┴─┼╥: ═╙-─╧╙ FILE READER FOR THE 128 AND 1571/81 DRIVES. ╘HIS ARTICLE PRESENTS A PROGRAM THAT READS ═╙-─╧╙ FILES AND THE ROOT DIRECTORY OF ═╙-─╧╙ DISKS. ╘HIS PROGRAM COPIES FILES FROM DISK TO DISK SO TWO DISK DRIVES ARE REQUIRED TO USE IT (OR A "VIRTUAL" DRIVE). ╘HIS SCHEME IMPOSES NO LIMIT ON THE MAXIMUM SIZE OF A FILE TO BE TRANSFERRED. ╘HE USER-INTERFACE CODE IS WRITTEN IN ┬┴╙╔├ AND PRESENTS A FULL-SCREEN FILE SELECTION MENU. ╘HE GRUNT-WORK CODE IS WRITTEN IN ASSEMBLY LANGUAGE AND OPERATES AT MAXIMUM VELOSITY. ├OMPLETE, EXPLAINED CODE LISITINGS ARE INCLUDED. ┬Y ├RAIG ┬RUCE. ============================================================================= ╠EARNING ═ACHINE ╠ANGUAGE - ╨ART 4 BY ├RAIG ╘AYLOR (DUCK@PEMBVAX1.PEMBROKE.EDU) +---------------------------+ ▄ ╙PACE ╔NVASION - ╨ART 1 ▄ ▄ ▄ ▄ ╨ROGRAMMING: ├RAIG ╘AYLOR ▄ ▄ ╟RAPHICS : ╨ASI ╧JALA ▄ ▄ ═USIC/╙OUND: ▄ ▄ ▄ +---------------------------+ ╔. ╔NTRODUCTION ------------ ╔N THIS AND FUTURE ╠EARNING ═ACHINE ╠ANGUAGE'S WE WILL DEVELOP A GAME CALLED ╙PACE ╔NVASION. ╘HE GAME WILL BE SIMILAIR TO ╙PACE ╔NDVADERS AND WILL RUN ON THE ├OMMODORE 64 OR THE ├OMMODORE 128 IN 80 COLUMNS. ╔T WILL FEATURE ALL THE "FEATURES" AND "PARTS" THAT ARE FOUND IN COMMERCIAL GAMES WITH INTERRUPT- DRIVEN MUSIC, CUSTOM CHARACTER DEFINITIONS, 100% MACHINE LANGUAGE, MULTI-LEVEL GAME PLAY, AND INPUT FROM THE KEYBOARD, JOYSTICK OR MOUSE. ╬OTE ▄ ╔ AM LOOKING FOR SOMEONE TO HELP AID MUSIC COMPOSITION THAT WILL -----+ BE INTRODUCED IN A LATER ISSUE. ╨ROGRAMMING OF THE 6502 IS HELPFUL BUT NOT A REQUIREMENT. ╨LEASE EMAIL ME AT DUCK@PEMBVAX1.PEMBROKE.EDU IF YOU ARE INTERESTED. ═ANY THANKS TO ╨ASI ╧JALA FOR HIS WORK WITH THE GRAPHICS IN THIS PROGRAM. ┴LSO PLEASE NOTE: ╘HIS ENTIRE PROGRAM HAS BEEN ASSEMBLED SUCESSFULLY WITH THE ┬UDDY-128 ASSEMBLER FOR BOTH THE ├=128 AND ├=64 VERSION. ─UE TO THE LENGTH OF THE SOURCE FILES (OVER 1,500 LINES) ╔'M NOT SURE IF ┬UDDY-64 WILL HANDLE IT. ╘HUS IF YOU GET ERRORS DURING ASSEMBLY, ALL ╔ CAN SAY IS: SORRY. ╔F THIS IS THE CASE THEN THE NEXT ISSUE WILL HANDLE DIVIDING THE PROGRAM AND DATA UP INTO SEGMENTS WHICH CAN THEN EACH BE LOADED SEPERATLY. ╔╔. ═ACHINE ╬OTES ------------- ╘HE ├OMMODORE 64 AND 128 PROGRAMS FOR ╙PACE ╔NVASION WILL DIFFER SLIGHTLY, MOSTLY IN THE FOLLOWING AREAS: - CUSTOM CHARACTER DEFINITION - MEMORY INITIALIZATION / SETUP - SOUND / MUSIC ┬ECAUSE THE ACTUAL GAME PLAY AND THE CHANGES NESSCESARY BETWEEN THE AREAS LISTED ABOVE, WE WILL USE THE ┬UDDY ┴SSEMBLER NOTATION FOR CONDITIONAL ASSEMBLY TO ALLOW THE DEVELOPMENT OF ONLY ONE FILE CONTAINING THE SOURCE CODE. ╔N ADDITION TO CONDITIONAL ASSEMBLY MOST OF THE ROUTINES WILL BE WRITTEN AS ONE WITH JUMPS TO SUBROUTINES CONTAINING THE ├64 OR 128 DIRECT CODE AS THE ALGORITHIMS ARE USUALLY THE SAME FOR EACH. ╔N ADDATION THERE WILL BE SEVERAL SOURCE FILES AND SOME MISCELLANEOUS INCLUDE FILES FOR GRAPHICS AND SOUND. ╞OR THOSE OF YOU WHO ARE OR WILL BE CONVERTING THE ASSEMBLY SOURCE OVER TO A DIFFERENT ASSEMBLER THE CONDITIONAL ASSEMBLY DIRECTIVES .IF (CONDITION) WILL ONLY BE TRUE IF THE CONDITION IS NON-ZERO. ╔E: IF THE SYMBOL COMPUTER IS DEFINED AS 128 THEN THE FOLLOWING EXAMPLE ILLUSTRATES IT: COMPUTER = 128 .IF COMPUTER-64 ; NON-ZERO ANSWER SO THEREFORE ; 128 CODE GOES HERE .ELSE ; 64 CODE GOES HERE .IFE ; END THE .IF CONDITION. ┴LSO NOTE THAT FOR MUCH OF THE PROGRAM WE WILL _NOT_ BE USING THE COMPUTER ROUTINES AND INSTEAD BE DEVELOPING OUR OWN. ╔N ADDITION THE PROGRAM WILL SHOW YOU HOW TO USE ╔╥╤ INTERRUPTS TO SIMPLIFY PROGRAMMING. ╫E WILL BE USING THEM TO PLAY MUSIC IN THE BACKGROUND ON THREE VOICES (SOUND EFFECTS WILL TEMPORARILY PRE-EMPT THE THIRD VOICE FROM PLAYING). ┴LSO ANIMATION OF CHARACTERS WILL BE DONE VIA THE ╔╥╤. ┴ LITTLE BACKGROUND ON INTERRUPTS FOR THOSE OF YOU WHO ARE A BIT HAZY ON WHAT THEY ARE OR HAVE NEVER SEEN THEM BEFORE (┴LSO TRY TAKING A LOOK AT ╥ASTERS: ╫HAT THEY ARE AND HOW TO USE THEM IN ├= ╚ACKING #3 - ╫HILE THIS DOES NOT NECESSARILY COVER WHAT WE ARE GOING TO BE USING INTERRUPTS FOR IT DOES DESCRIBE THEM QUITE WELL.) ┬ASICALLY THE COMPUTER GENERATES AN INTERRUPT EVERY 1/60TH A SECOND FROM A TIMER ON THE COMPUTER (USUALLY FROM THE ├╔┴ CHIP OR THE SCREEN FOR THOSE OF YOU WHO ARE CURIOUS). ╘HE COMPUTER WILL SAVE ALL THE REGISTERS, JUMP TO A SUBROUTINE - PERFORM THE INSTRUCTIONS THERE (USUALLY UPDATING TIME, SCANNING THE KEYBOARD ETC...) AND THEN RECALL ALL THE REGISTERS AND RETURN TO THE USER PROGRAM. ╘HIS IS AN INTERRUPT. ┴N ╔╥╤ INTERRUPT DESCRIBES AN INTERRUPT THAT WE CAN ALLOW TO BE "TURNED ON" AND "TURNED OFF" - IE: WE CAN TEMPORARILY DISABLE IT IF WE HAVE TO. ┴ ╬═╔ INTERRUPT DESCRIBES AN INTERRUPT WHICH WE CAN _NOT_ TEMPORARILY DISABLE -- WE WILL NOT BE USING ╬═╔ INTERRUPTS IN THIS PROGRAM. ╔╔╔. ╘HE ╨ROCESS ----------- ╨ART OF WHAT THIS SERIES OF ARTICLES IS FOCUSED AT IS THE DEVELOPMENT OF BEING ABLE TO ANALYZE PROGRAMMING TASKS AND BREAK THEM DOWN INTO SMALLER WORKABLE PROBLEMS. ╧NCE THESE PROBLEMS OR SUBROUTINES ARE COMPLETED YOUR ORIGINAL PROBLEM IS SOLVED. ╠ET'S TAKE THIS APPROACH TO ╙PACE ╔NVASION: ╨ROBLEM ╙TATEMENT: ┬UILD A ╙PACE ╔NVADER PROGRAM CALLED ╙PACE ╔NVASION. ----------------- ╒SUALLY, GIVEN A PROBLEM YOU HAVE TO RE-WORK THE PROBLEM STATEMENT TO ENCOMPASS ALL OF WHAT YOU WANT. ╠ET'S TRY AGAIN: ╨ROBLEM ╙TATEMENT: ─EVELOP A ╙PACE ╔NVADER PROGRAM CALLED ╙PACE ╔NVASION ----------------- UTILIZING THE 64 OR 128 SCREEN WITH INTERRUPT DRIVEN MUSIC / SOUND, AND ALLOWING INPUT FROM THE KEYBOARD, JOYSTICK OR MOUSE. ╚MMM... ╘HE PROBLEM STATEMENT LISTED ABOVE IS BETTER BUT IT HAS NO REAL ORDER; WE HAVE NO CLEAR IDEA OF WHERE TO START AND WHAT WE NEED TO DO. ╔T DOES HOWEVER TELL US THAT WE HAVE THE FOLLOWING SECTIONS: - 64 / 128 ╙CREEN ╚ANDLING - ═USIC / ╙OUND - ╔NPUT ╚ANDLING - ╟AME ─RIVER (IMPLIED) ╠ET'S THINK A BIT MORE ABOUT EACH OF THESE SECTIONS AND WHAT EACH WILL INVOLVE: 128 / 64 ╙CREEN ╚ANDLING: - ╨UTTING CHARACTERS ON SCREEN. ------------------------ - ╔NITIALIZING THE ╙CREEN / ╥EGISTERS. - ╙ETTING UP THE ├USTOM ├HARACTERS. - ╚ANDLING ANY ┴NIMATION. ═USIC / ╙OUND: - ╙ETTING UP THE ╙OUND ├HIP ╥EGISTERS. ------------- - ╨LAYING A NOTE READ FROM ═EMORY. - ┼XECUTING A ╙OUND ┼FFECT. ╔NPUT ╚ANDLING: - ─EVICE ╙ELECTION (KEYBOARD, MOUSE, JOYSTICK). -------------- - ╦EYBOARD ╙CANNING. - ═OUSE ╙CANNING. - ╩OYSTICK ╙CANNING. ╟AME ─RIVER: - ╘ITLE ╙CREEN. ----------- - ╔NITIALIZATION OF ═EMORY. - ╠EVEL ╙ETUP. - ═OVEMENT OF ┴LIENS. - ═OVEMENT OF ═ISSLES. - ═OVEMENT OF ╨LAYER. - ├OLLISION ├HECKING. - ├OLLISION ╚ANDLING. - ┼ND OF ╠EVEL. - ╙CORE ╒PDATING. - ┼ND - ╟AME HANDLING. - ╚IGH ╙CORE ╒PDATE. ╙HREW! ╠ONG LIST 'EH? - ╬OW YOU MAY HAVE THOUGHT OF SOME NOT LISTED ABOVE, AND WE MAY HAVE POSSIBLY OVERLOOKED SOME CRUCIAL ROUTINES -- THAT'S FINE -- THE ABOVE IS JUST INTENDED AS A BUILDING BLOCK - A PLACE TO START CODING FROM. ╔F WE THINK OF THESE AS SUBROUTINES WE CAN BUILD A SKELETON OUTLINE OF THE PROGRAM - YET WE NEED SOME ORDER IN HOW WE CALL THEM. ╧BVIOUSLY WE AREN'T GOING TO MOVE THE PLAYER UNTIL WE SCAN THE INPUT AND THAT REQUIRES PRIOR DEVICE SELECTION ETC... ╚MM... ╘AKING ORDER INTO ACCOUNT WE CAN RE-STATE THE PROBLEM AS: ╨ROBLEM ╙TATEMENT: ─EVELOP A GAME SIMILAIR TO ╙PACE ╔NVADERS CALLED ╙PACE ----------------- ╔NVASION BY INITIALIZING MEMORY, THE DISPLAY DEVICE, SETTING UP ├USTOM ├HARACTERS, SETTING UP THE ═USIC ╥EGISTERS AND DISPLAYING THE TITLE SCREEN. ╞ROM THERE, SELECT THE INPUT DEVICE AND AFTER THAT SETUP THE CURRENT LEVEL. ╬EXT, WHILE PLAYING MUSIC IN THE BACKGROUND AND SCANNING THE INPUT DEVICE, MOVE THE ALIENS, MISSLES AND PLAYER CHECKING FOR COLLISIONS AND TAKING APPROPRIATE ACTION AS REQUIRED (PLAYER DIES, SCORE INCREASES ETC OR WHAT-NOT). ┴FTER EACH LEVEL DISPLAY IF THE PLAYER IS DEAD, OR SET-UP FOR THE NEXT LEVEL AND REPEAT. ╫HEN THE GAME HAS ENDED UPDATE THE HIGH SCORE IF NECESSARY. ╘RY SAYING THAT FIVE TIMES REAL FAST! :-) ┬UT THAT PROBLEM STATEMENT IS A WHOLE LOT BETTER THAN THE ONE WE HAD AT THE BEGINNING WHICH SIMPLY SAID TO DEVELOP A GAME. ╔╓. ╬OT ┴LL ┴T ╧NE ╘IME - ╫HAT ╫E'RE ─OING ╘HIS ╘IME ------------------------------------------------ ╬OW THIS PROGRAM IS TOO COMPLEX, (AS SEEN BY THE PROBLEM STATEMENT ABOVE) TO HAVE IN ONE ARTICLE SO THIS ISSUE WE'LL CONCENTRATE ON THE BASIC MAIN LOOP AND THE INITIALIZATION OF THE ├USTOM ├HARACTERS AND THE TITLE SCREEN. ╧RIGINALLY, ╔ WAS PLANNING ON UPDATING AND LISTING THE REVISED CODE IN EACH ISSUE. ╚OWEVER, DUE TO SPACE LIMITATIONS AND THE ENORMITY OF THE PROGRAM CURRENTLY (1,500+ LINES!!) IT WILL BE PLACED FOR ANONYMOUS FTP AT CCOSUN.CALTECH.EDU UNDER THE DIRECTORY: PUB/RKNOP/╚┴├╦╔╬╟.═┴╟. ╓. ╘HE ═AIN ╠OOP ------------- ╫HAT IS A MAIN LOOP? ┬ASICALLY IT'S WHERE EVERYTHING GETS DONE. ╔T CALLS OTHER SUBROUTINES AND KEEPS REPEATING UNTIL CERTAIN CRITERIA ARE MET - USUALLY WHEN THE PLAYER REQUESTS TO EXIT THE GAME. ╚OWEVER, INSIDE YOU'LL FIND INNER LOOPS FOR LEVEL PLAY ETC. ╧UR MAIN LOOP FOR THIS PROGRAM WILL BE: ------------------------------------------------------------------------------- ;; * ═AIN ╠OOP - ╘HIS SHOULD BE THE LAST SECTION IN THE SOURCE CODE. ; ; ═AIN ╠OOP ; MAIN'LOOP = * JSR MEMORY'SETUP ; ╙ET-╒P MEMORY. JSR DISPLAY'SETUP ; " " DISPLAY. JSR CHAR'SETUP ; " " CUSTOM CHARACTER DISPLAY. JSR MUSIC'SETUP ; " " MUSIC CHIP. JSR TITLE'SCREEN ; ─ISPLAY THE TITLE SCREEN. JSR SELECT'INPUT ; ╙ELECT ╔NPUT ─EVICE. LEVEL'LOOP = * JSR PLAY'MUSIC ; ╙TART THE MUSIC PLAYING. JSR SETUP'LEVEL ; ╙ETUP THE CURRENT LEVEL. - JSR ALIEN'MOVE ; ═OVE ALIENS JSR MISSLE'MOVE ; " MISSLES JSR PLAYER'MOVE ; " PLAYER JSR CHECK'COLLISION ; ├HECK FOR COLLISIONS LDX COLLISION'FLAG ; ├HECK COLLISION FLAG. BEQ - DEX ; ─ECREASE .╪ BY 1 SO IF ╪ WAS 1 THEN BEQ PLAYER'DIE ; IT'S NOW 0 SO WE KNOW PLAYER DIED. DEX ; ─ECREASE .╪ AGAIN SO IF ╪ WAS 2 THEN BEQ ALIEN'DIE'SOUND ; IT'S NOW 0 SO WE MAKE ALIEN DEATH. JSR END'LEVEL ; ╔F WE GOT HERE - THAN END OF LEVEL. JSR WAIT'NEXT ; ╫AIT FOR NEXT KEYPRESS. JSR INCREASE'LEVEL ; INCREASE LEVEL #. SEC ; ┴ND GO BACK.... BCS LEVEL'LOOP ALIEN'DIE'SOUND = * JSR MAKE'ALIEN'SOUND ; MAKE ALIEN SOUND. SEC ; SET CARRY BCS - ; AND JUMP BACK. PLAYER'DIE JSR SHOW'PLAYER'DIE ; ╙HOW IT ON-SCREEN. LDA LIVES ; ├HECK # OF LIVES. BEQ END'OF'GAME ; ╔F 0 THE END-OF-GAME. BNE LEVEL'LOOP ; GO BACK AND RE-START LEVEL. BRK ; ╔F WE GET HERE - THAN AN ERROR. END'OF'GAME JSR END'GAME'SCREEN ; ╙HOW END-OF-GAME SCREEN. JSR HIGH'SCORE'UPDATE ; ╒PDATE THE HIGH SCORE IF NEED-BE. JSR WAIT'NEXT ; ╫AIT FOR NEXT-GAME SELECTION. LDA QUIT BEQ + JSR SETUP'LEVEL'1 ; ╙ET-╒P FIRST LEVEL. SEC BCS LEVEL'LOOP ; AND START PLAYING IT. + JMP QUIT'GAME ; ; ┼ND OF ═AIN ╠OOP ; ------------------------------------------------------------------------------- ╙OME OF THE ROUTINES LISTED ABOVE WE WILL LATER REPLACE WITH ACTUAL CODE. ╔T'S MUCH EASIER TO SEE: INC LEVEL THAN TO SEE A JSR INCREASE'LEVEL AND TRY TO HUNT DOWN THE CODE. ╔'VE INCLUDED THEM IN FOR NOW SO THAT WE CAN HAVE A BETTER IDEA OF WHAT IS GOING ON. ╔N THE FILE: INVASION.SRC MOST OF THE STATEMENTS ABOVE ARE COMMENTED OUT. ╧NCE WE WRITE THE ROUTINES WE'LL UN-COMMENT THEM. ╞OR NOW, THIS SERVES TO STILL REMIND US OF THE ROUTINES WE NEED TO WRITE. ┴LSO THERE ARE A COUPLE OF PROGRAMMING TRICKS THAT ╔ USED IN THE MAIN LOOP THAT PROBABLY NEED SOME CLARIFYING. ╫HEN HANDLING THE COLLISIONS THE .╪ REGISTER IS LOADED WITH THE RESULT OF THE COLLISION CHECKING - $00 = NO COLLISIONS, $01 = PLAYER DIED, $02 = ALIEN DIED, $03 = END OF LEVEL. ┴NYTIME A LOAD TO A REGISTER IS DONE THE FLAGS ARE AUTOMATICALLY SET AS IF YOU HAD COMPARED IT TO 0 - HENCE WE CAN LDX THE COLLISION FLAG AND IMMEDIATELY BRANCH IF EQUAL TO ZERO FOR NO COLLISIONS. ╔N ADDITION TO THE LOAD ANYTIME THE .╪ OR .┘ REGISTERS ARE INCREMENTED OR DECREMENTED AN IMPLICIT COMPARISON TO ZERO IS PERFORMED. ╙O IF THE .╪ REGISTER IS 1 PREVIOUSLY, WE DECREMENT IT THEN IT WILL BE ZERO AND OUR ┬┼╤ INSTRUCTION WILL BRANCH. ╔F IT'S TWO THEN IT WILL BE ONE AND WE CAN CONTINUE LIKE THIS. [╬╧╘┼: ╘ECHNICALLY IT'S NOT A REAL COMPARISON TO ZERO BUT CALLING IT A COMPARISON TO ZERO SERVERS OUR PURPOSE HERE. ╘HE ONLY SIGNIFICANT DIFFERENCE WOULD BE IN THE EFFECT OF THE CARRY FLAG WHICH IS INSIGNIFICANT IN OUR CODE SEGMENT HERE.] ┴LSO IN SEVERAL LOCATIONS ARE THE TWO INSTRUCTIONS: SEC BCS [LABEL] ╫HAT THESE ARE DOING ARE SIMPLY PROGRAMMING STYLE - THEY COULD BE SUBSTITUTED WITH ╩═╨ [LABEL] - HOWEVER THEY OFFER ADVANTAGES OVER ╩═╨. ╘HEY TAKE UP THE A LARGER AMOUNT OF EXECUTION TIME, HOWEVER THEY ARE RELOCATABLE SO ANY MUCKING AROUND / MOVING SECTIONS OF CODE DURING DEBUGGING WILL BE LESS LIKELY TO CRASH. ╒SING OTHER FLAGS ARE ALSO VALID -- THE USE OF WHICH FLAG (╔ PREFER THE CARRY FLAG) IS USUALLY DEPENDENT ON THE PROGRAMMER. ╟EOS DEFINES A SIMILAIR MACRO CALLED ┬╥┴ (BRANCH ALWAYS) WHICH IS EQUIVLENT TO: CLV BVC [LABEL] ╬OTE THAT THE ABOVE IS JUST PROGRAMMING STYLE, HELD OVER FROM MY PROGRAMMING IN ASSEMBLY DAYS. ╘HE USE OF ╩═╨ IS PROBABLY PREFERABLE IN TERMS OF EXECUTION AND ALSO IN BEING ABLE TO BRANCH MORE THAN 127 BYTES AWAY (THE BRANCH INSTRUCTIONS ONLY HAVE A RANGE OF +128/-127). ╓╔. ├USTOM ├HARACTERS ----------------- ╙INCE WE'RE WRITING FOR EACH OF THE SEPERATE MODES (64 MODE, 128 MODE) WE HAVE TO TAKE A LOOK AT THE DIFFERENCES BETWEEN THE ╓╔├ CHIP (64 MODE) AND THE 8563 CHIP IN THE 128. ╘HE ╓IC-├HIP ------------ ╘HE CHARACTER SETS IN THE ╓╔├ CHIP ARE DEFINED AS IN THE EXAMPLE BELOW OF THE CHARACTER CODE $00 "@" (ALL REFERENCES ARE TO SCREEN "POKE" CODES - NOT PRINT CODES). .BYT #%00111100 ╘RY HOLDING THE PAGE (OR MOVING AWAY FROM THE .BYT #%01100110 SCREEN) AND TAKING A LOOK AT THE PATTERNS THE 1'S .BYT #%01101110 AND 0'S MAKE. ┼ACH CHARACTER IS THUS DEFINED AS .BYT #%01101110 EIGHT BYTES WHO'S BIT PATTERNS DEFINE IT. ╚AVING A .BYT #%01100000 TOTAL OF 256 CHARACTERS AVAILABLE MAKES IT .BYT #%01100010 NECCESARY TO SET ASIDE A TOTAL OF 2,048 BYTES. .BYT #%00111100 .BYT #%00000000 ╬OW, INSTEAD OF DESIGNING ALL 256 CHARACTER SETS WE'LL JUST TAKE ADVANTAGE OF THE FACT THAT THE LETTERS AND NUMBERS WE WANT WILL ALREADY BE THERE -- WE'LL JUST COPY THEM FROM THE ╥╧═ SET INTO ╥┴═, MODIFY SOME OF THE OTHER CHARACTERS TO REFLECT WHAT WE WANT AND THEN TELL THE ╓╔├ CHIP TO LOOK AT ╥┴═ TO GET THE CHARACTER SET DEFINITIONS. ╘HERE ARE SOME PROBLEMS WITH COPYING THE 'SYSTEM' CHARACTERS, HOWEVER. ╘HE ├OMMODORE 64 USUALLY MASKS OUT THE CHARACTER SET AND TYPICALLY IT IS ONLY AVAILABLE TO THE ╓╔├ CHIP SO THAT MORE SPACE CAN BE PRESENT FOR USER PROGRAMS AND SUCH. ╔T ALSO TAKES UP THE SECTION OF MEMORY THAT THE ╔/╧ BLOCK IN $D000-$DFFF DOES SO THAT SWITCHING IT IN WHILE INTERRUPTS ARE ENABLED IS SURE TO RESULT IN A CRASH. ╫E'RE ALSO GOING TO BE DOING A FEW THINGS THAT YOU MAY NOT EXPECT -- INSTEAD OF COPYING ALL 256 CHARACTERS - WE'RE GONNA _JUST_ COPY THE FIRST 128. ╘HIS WILL GIVE US ALL OF THE NORMAL CHARACTERS AS THE LAST 128 ARE THE REVERSE- VIDEO COUNTERPARTS TO THE FIRST 128 CHARACTERS. ╫E'RE DOING THIS TO CONSERVE SPACE AND BECAUSE WE REALLY DON'T NEED THAT MANY CHARACTERS DEFINED. ┴LSO LOCATION $01 CONTAINS WHAT $D000-$DFFF HOLDS AND WE WILL HAVE TO MODIFY BIT 2 TO SWITCH THE CHARACTER ╥╧═ IN. ╚ENCE, THE FOLLOWING PROGRAM CODE IS USED TO COPY THE CHARACTER SET: ------------------------------------------------------------------------------- COPY'CHARS = * ; MUST BE RUN W/ INTERRUPTS DISABLED LDA $01 ; REGISTER 1 = THE CONTROL TO SWITCH IN THE CHAR. ; ROM. PHA ; SAVE IT AS WE'LL LATER NEED TO STA' IT BACK. AND #%11111011 ; ┬IT 2 CONTROLS IT - CLEAR IT TO SWITCH IT IN. STA $01 ; AND MAKE IT SO WE CAN READ IT IN. LDA #>$3000 ; MOVE CHARS TO $3000 STA DEST+1 LDA #>$D800 ; FROM $D800 (START OF CHAR SET) (LOWER-CASE) STA SRC+1 LDY #$00 ; LO-BYTES OF BOTH SRC, DEST = $00. STY SRC STY DEST LDX #$10 ; COPY 2K OF DATA. - LDA (SRC),Y ; COPY BYTE. STA (DEST),Y INY BNE - ; CONTINUE UNTIL .┘ = 0. INC SRC+1 ; INCREASE SOURCE & DEST BY 256 INC DEST+1 DEX ; DECREASE .╪ COUNT. BNE - ; IF NON-ZERO THEN CONTINUE COPYING, ELSE PLA ; RESTORE VALUE OF $01 STA $01 ; AND PUT BACK. LDA $D018 ; SET ╓╔├-CHIP ADDRESS. AND #$F1 ; TO SHOW CHAR SET. ORA #$0C STA $D018 ; AND FINALLY TELL ╓╔├ WHERE THE CHAR SET IS... RTS ; AND RETURN. ------------------------------------------------------------------------------- ╬OTE THAT WE STILL NEED TO CHANGE THE ACTUAL CHARACTERS WE'RE GONNA BE USING. ╘HAT WILL BE HANDLED IN THE SECTION AFTER NEXT: ├HANGING THE ├HARACTERS AS THERE IS A GREAT DEAL OF SIMILARITY BETWEEN THE 128 AND 64 IMPLEMENTATIONS. ╘HE 8563 ├HIP ------------- ╘HE 8563 80-├OLUMN CHIP USUALLY HAS 16K OR 64K ╥AM ATTATCHED TO THE CHIP WHICH THE ├╨╒ DOES NOT HAVE DIRECT CONTROL OVER. ╔T HAS TO DIRECT THE 8563 TO STORE AND RETRIEVE VALUES TO THAT MEMORY. ╫HAT MAKES CONTROL OVER THAT MEMORY ALL THE MORE DIFFICULT IS THE FACT THAT THE 8563 ONLY HAS TWO LINES OR ADDRESSES THAT THE ├╨╒ CAN CONTROL. ╘HE 8563 HAS A CHARACTER SET IN MUCH THE SAME WAY THE ╓╔├ CHIP DOES, SAVE ONE EXCEPTION - EACH CHARACTER SET CAN HAVE UP TO 16 LINES. ╬ORMALLY, THE LAST EIGHT LINES ARE FILLED WITH $00 AND ARE NOT SHOWN. (╨ROVISIONS CAN BE MADE TO HAVE 8X16 CHARACTERS BUT IT IS NOT NEEDED FOR THIS GAME AND THUS, WILL NOT BE SHOWN - ╞OR MORE INFORMATION ╙EE ├= ╚ACKING ╔SSUE #2: 8563: ┴N ╔N-─EPTH ╠OOK.) ╘HUS THE ALGORITHIM IS SIMILAIR TO THE ├=64 BUT 8 ZERO-BYTES WILL NEED TO BE WRITTEN AT THE END OF EVERY EIGHT BYTES READ. ╚OWEVER, THE 8563 DOES MAKE THINGS EASIER FOR US! - ╫HEN THE COMPUTER IS FIRST TURNED ON A COPY OF THE ├HARACTER ╙ET FROM ╥╧═ IS COPIED INTO THE 8563. ╘HE 8563 HAS NO ╥╧═ ├HARACTER ╙ET ASSOCIATED WITH IT AND THUS WE ARE ABLE TO JUST SIMPLY MODIFY THE CHARACTER SET THAT IS IN THE 8563 MEMORY INSTEAD OF COPYING IT OVER. ┬ECAUSE OF THIS NO ROUTINE WILL BE PRESENTED TO COPY A CHARACTER SET INTO THE 8563 MEMORY, RATHER THE DISCUSSION OF COPYING INDIVIDUALLY DEFINED CHARACTERS WILL TAKE PLACE IN THE NEXT SECTION. ╘HE ├=128 ALSO MAKES LIFE EVEN EASIER FOR US AT THE END WHEN WE WILL EXIT THE PROGRAM, MODIFYING THE CHARACTER SET BACK TO THE "STANDARD" ├OMMODORE CHARACTER SET BY A ROUTINE IN THE ╦┼╥╬┴╠ THAT WILL COPY THE CHARACTERS BACK. ╫E'LL TAKE A LOOK AT IT CLOSER WHEN WE WRITE THE EXIT ROUTINE. ┴LSO NOTE THAT SINCE THE 8563 CHIP SUPPORTS THE 80 COLUMN SCREEN WE WILL BE DEFINING TWO CHARACTERS THAT CAN BE PLACED SIDE BY SIDE FOR EACH ALIEN SO THAT THE PLAYING FIELD WILL BE SIMILAIR TO THE ├64 VERSION. ╚OWEVER, FOR THE TITLE SCREEN WE WILL BE SWITCHING THE 8563 INTO A "40 COLUMN" MODE TO MAKE PROGRAMMING EASIER, IN ADDITION TO EXPANDING THE CHARACTER BIT-MAPPED LOGO. ├HANGING THE ├HARACTERS ----------------------- ┴ LOT OF THE TIMES YOU'LL FIND YOURSELF RE-USING SUBROUTINES AND CODE THAT YOU HAVE PREVIOUSLY CREATED, GRADUALLY, OVER A PERIOD OF TIME BUILDING UP A LIBRARY OF ROUTINES. ╫HEN THINKING THROUGH THE PURPOSE AND INTENT OF THIS ROUTINE ╔ THOUGHT ABOUT POSSIBLY BUILDING IT SO IT WOULD READ A TABLE AND CHANGE THE CHARACTER SET BASED ON THAT TABLE. ╘HE 64/128 CHARACTER SETS WOULD BE THE SAME - THIS ROUTINE WOULD AUTOMATICALLY GENERATE THE EIGHT ADDITIONAL BYTES NEEDED BY THE 8563 IF NEED-BE AND IT WOULD CALL THE APPROPRIATE STORAGE ROUTINE - STORE TO EITHER THE 8563 OR THE COMPUTER MEMORY. ╬OW YOU MAY BE ASKING WHY WOULD YOU WANT TO STORE TO THE COMPUTER MEMORY IN 128 MODE? ╫HY NOT JUST HAVE TWO SEPERATE VERSIONS? - ┘ES - THAT COULD BE POSSIBLE BUT ╔'M IMPLEMENTING IT THIS WAY BECAUSE IN THE FUTURE ╔ MAY SEE A NEED TO DEFINE CUSTOM CHARACTERS IN 128 MODE FOR THE 40 COLUMN SCREEN. ╘HIS WAY ╔ CAN JUST EXTRACT THE ROUTINE, POP IT INTO MY PROGRAM AND ╔'VE GOT THAT SECTION OF THE CODE COMPLETE. ╘HIS IS WHAT ╔ WAS THINKING OF FOR THE DATA TABLE: .BYT 1 = 8563, 0 = COMP. MEMORY. .WORD ADDRESS ; ADDRESS BASE OF CHAR-SET IN COMPUTER OR 8563 MEMORY. .BYTE CHAR # ; (TO START) .BYTE # OF CHARS TO DEFINE .BYTE # OF CHARACTERS TO DEFINE .BYTE DATA,DATA,....,DATA8 ; CHARACTER DATA. .BYTE DATA,DATA,....,DATA8 ; CHARACTER DATA. ETC.... . . . ┼NTRANCE INTO THE ROUTINE WILL CONSIST OF .┴┘ HOLDING THE LOCATION OF THE TABLE. ╫E WILL KEEP THE ADDRESS OF THE TABLE AND KEEP INCREMENTING IT AS WE GO ALONG IN Z-PAGE LOCATIONS. ------------------------------------------------------------------------------- INSTALL'CHAR = * STA ZP1 ; SAVE .AY IN TABLE ADDRESS STY ZP1+1 LDY #$00 ; READ COMPUTER MODE. JSR GET'BYTE STA MODE JSR GET'BYTE ; GET ADDRESS BASE. STA ADR JSR GET'BYTE STA ADR+1 JSR GET'BYTE ; GET NUMBER OF CHARACTERS TO COPY. STA NUMB JSR GET'BYTE ; GET NEXT CHARACTER #. STA WRK ; SAVE IN TEMP. LOCATION. LDA #$00 STA WRK+1 ASL WRK ; SHIFT LEFT X3 TIMES = *8 ROL WRK+1 ASL WRK ROL WRK+1 ASL WRK ROL WRK+1 LDA MODE ; IF FOR 8563 THEN MULTIPLY 1 MORE TIME. BEQ + ASL WRK ROL WRK+1 + LDA ADR ; ADD CHARACTER ADDRESS IN. CLC ADC WRK STA WRK LDA ADR+1 ADC WRK+1 STA WRK+1 ; ADDRESS NOW CALCULATED JSR SETADRS ; SET ADDRESS IN PROPER CHIP LOOP'INSTALL LDX #$08 ; COPY 8 BYTES. - JSR GET'BYTE JSR WRITEBYTE ; WRITE OUT BYTE. DEX BNE - LDA MODE ; IF 128 THEN FILL OUT 8 MORE $00 BYTES. BEQ + LDA #$00 LDX #$08 - JSR WRITEBYTE DEX BNE - + DEC NUMB BNE LOOP'INSTALL RTS ------------------------------------------------------------------------------- ╫HAT? ╫E HAVE THRE SUBROUTINES : WRITEBYTE, SETADRS, AND GET'BYTE THAT WE HAVEN'T EXAMINED YET. ╘HESE ARE GOING TO BE THE ROUTINES THAT ARE DEPENDANT ON THE COMPUTER TYPE. ┴LSO, WRITEBYTE WILL REQUIRE THAT .╪┘ NOT BE DISTURBED; SETADRS REQUIRES THAT .┘ NOT BE DISTURBED HENCE THE FOLLOWING: ------------------------------------------------------------------------------- SETADRS TYA ; SAVE .YX PHA TXA PHA LDA MODE ; CHECK COMPUTER TYPE. BEQ + ; IF ├=64, THEN JUMP AHEAD. LDX #18 ; ╓─├ REGISTER - CURRENT MEMORY ADDRESS HI LDA WRK+1 ; GET ADDRESS HI JSR WR'VDC LDX #19 ; ╓─├ REGISTER - CURRENT MEMORY ADDRESS LO LDA WRK ; GET ADDRESS LO JSR WR'VDC + PLA ; RESTORE .╪┘ TAX PLA TAY RTS ; AND RETURN. ------------------------------------------------------------------------------- ╬OTE THAT WE REALLY DON'T NEED A SETADRS FOR THE ├=64 -- WE CAN JUST INDEX OFF (WRK) IN THE WRITEBYTE ROUTINE WHICH FOLLOWS: ------------------------------------------------------------------------------- WRITEBYTE STA TEMP ; SAVE AS WE NEED IT LATER. TXA ; ╙AVE .╪┘ PHA TYA PHA LDA MODE ; NOW CHECK COMPUTER TYPE. BEQ + ; IF C64 JUMP AHEAD LDA TEMP ; RECALL TEMP. JSR WR'VRAM SEC BCS ++ ; JUMP AHEAD + LDY #$00 ; ├64 / Y-INDEX = $00 LDA TEMP ; GET VALUE STA (WRK),Y ; STORE INC WRK ; NOW INCREASE ADDRESS BNE + INC WRK+1 + PLA ; NOW RETURN AFTER RECALLING .╪┘ TAY PLA TAX RTS ; AND RETURN. ------------------------------------------------------------------------------- ╬OTE THAT THE FOLLOWING ROUTINE IS FAIRLY SHORT BUT IT IS CALLED NUMEROUS TIMES WITHIN THE ROUTINES THAT USE DATA TABLES SUCH AS INSTALL'CHAR, WRITE'TXT AND WRITE'COL. ------------------------------------------------------------------------------- GET'BYTE = * LDA (ZP1),Y INY BNE + ; IF ZERO THEN INCREASE ZP1 HI INC ZP1+1 + RTS ------------------------------------------------------------------------------- ╬OT BAD 'EH? ┴ QUICK NOTE: ╘HE INSTRUCTIONS: ╨╠┴, ╘┴┘, ╨╠┴, ╘┴╪, ╨╚┴, ETC.. ARE ROUTINES THAT ╨USH OR ╨ULL (PHA,PLA) THE .┴ ONTO THE STACK. ╘HE ╘┴┘, ╘┴╪, ╘╪┴, ╘┘┴ ARE INSTRUCTIONS THAT TRANSFER A REGISTER TO ANOTHER (IE: THE ╘┴┘ TRANSFERS THE ┴ REGISTER TO .┘, ╘╪┴ TRANSFERS .╪ TO .┴ ETC...) ┬Y USING THE COMBINATION OF THESE WITH THE STACK WE CAN SAVE THE REGISTERS AND LATER RE-CALL THEM SO THAT THEY ARE THE SAME WHEN WE ENTERED THE ROUTINE. ╘HE STACK IS USUALLY A "MYSTERY" ITEM TO NEW PROGRAMMERS OF THE 6502 SERIES. ┬ASICALLY IT'S JUST LIKE ANY OTHER STACKS IN THE REAL WORLD - THE LAST ITEM THROWN (╔'M NON-PRACTICING PERFECTIONIST SO ╔ THROW STUFF.. ;-) ) OR PUSHED ON THE STACK WILL THE FIRST ITEM REMOVED OR PULLED FROM THE STACK. ╞OR EXAMPLE ╔'VE GOT A STACK OF BOOKS SITTING NEAR ME : ═APPING THE ├OMMODORE 128 128 ╔NTERNALS AND ╔'M HOLDING ═APPING THE ├OMMODORE 64 IN MY HANDS. ╔F ╔ PUSH (OR TOSS) THE BOOK ONTO THE STACK (AND HOPEFULLY HIT THE STACK INSTEAD OF THE FLOOR) ╔'LL HAVE THE FOLLOWING STACK: ═APPING THE ├OMMODORE 64 ═APPING THE ├OMMODORE 128 128 ╔NTERNALS AND IT SHOULD BE EASY TO SEE THAT IF ╔ "PULL" THE NEXT BOOK OFF THE STACK THAT ╔'LL GET THE ═APPING THE ├OMMODORE 64 BOOK. ╘HE NEXT BOOK TO BE "PULL"ED AFTER THAT WOULD BE THE ═APPING THE ├OMMODORE 128 BOOK. ╘HIS IDEA CAN BE APPLIED TO THE 6502 STACK -- ╔T WILL KEEP STORING VALUES (UP TO 256) WHEN YOU "PUSH" THEM ON (VIA THE ╨╚┴ INSTRUCTION) AND WILL RETRIEVE THE LAST VALUE STORED WHEN YOU "PULL" THEM OFF (VIA THE ╨╠┴ INSTRUCTION). ┴NOTHER ╨╠┴ INSTRUCTION WOULD RETURN THE NEXT VALUE THAT HAD BEEN STORED. ╘HE ├HARACTER ┬ITMAPS --------------------- ╨ASI ╧JALA IS TO BE CREDITED WITH ALL THE GRAPHICS AND MANY THANKS GO OUT TO HIM. ╘HE GAME LOGO IS MADE UP OF 120 CUSTOM DEFINED CHARACTERS THAT WILL BE PRINTED IN THE FOLLOWING MANNER (ON THE 128 SCREEN THEY WILL BE CENTERED). (IN REVERSE VIDEO)... ┴┬├─┼╞╟╚ . . . [UP TO 40 CHARACTERS] ╔╩╦╠═╬╧╨ ╤╥╙╘╒╓╫╪ AND EVERYTHING WILL LINE UP. ╙O THAT IT WILL LOOK LIKE A "MINI-BITMAP". ╫E COULD HAVE USED BITMAP MODE AND MADE A VERY NICE LOOKING TITLE SCREEN BUT THAT WOULD HAVE INVOLVED SWITCHING AND ALLOCATING MEMORY FOR THE BITMAP, ETC . . . ╧N BOTH THE 8563 AND THE ╓╔├ THAT INVOLVES A BIT MORE WORK AND SO CUSTOM CHARACTERS WILL BE USED FOR THE TITLE SCREEN. ╘HE REGULAR LETTER AND NUMERIC CHARACTERS WILL BE AVAILABLE SO THAT WE CAN DISPLAY CREDITS AND GAME INSTRUCTIONS BELOW THE LOGO. ╬OW - IN THE PROGRAM LISTING WE COULD LIST THEM AS BINARY #'S AND THAT WOULD MAKE EDITING THEM VERY EASY BUT WE'RE GONNA USE THEIR DECIMAL REPRESENTATION IN THE PROGRAM LISTING. ╘HE CHARACTERS ARE DEFINED SIMILAIR TO THE LOGO EXCEPT THEY ARE TREATED AS SINGLE CHARACTERS. ╔N THE 128 VERSION DUE TO THE 80 COLUMN SCREEN WE ARE GOING TO USE TWO CHARACTERS SIDE BY SIDE TO SIMULATE ONE ALIEN SO THAT THE PLAYING FIELD WILL BE SIMILAIR TO THE ├64 VERSION. ╔N ADDATION, DURING THE MAIN LOOP WE WILL MODIFY THE CHARACTER SETS TO SUPPORT ANIMATION OF THE ALIENS. ╔N THE DATA LISTING THERE IS A REFERENCE TO "FRAMES" - FOR EACH OF THE ALIENS THERE ARE 8 DIFFERANT FRAMES. ╧H! - ╘HERE WILL BE MORE CHARACTERS DEFINED IN THE FUTURE. ╥IGHT NOW ╔'M MAINLY INTERESTED IN GETTING SOME BASE CHARACTERS DOWN SO YOU CAN SEE HOW CUSTOM CHARACTERS ARE IMPLEMENTED. ╫HEN WE START SETTING UP DIFFERENT LEVELS AND SUCH WE'LL ADD MORE CHARACTERS THEN. ├URRENTLY THE CUSTOM CHARACTERS ARE NOT USED - ONLY THE CHARACTERS FOR THE LOGO. ╞OR THOSE OF YOU WHO ARE CURIOUS TRY INSTALLING THE CHARACTERS VIA INSTALL'CHAR AND TAKING A LOOK AT THE ALIENS. ╓╔╔. ╘ITLE ╙CREEN ------------ ╘HE TITLE SCREEN IS USUALLY A LEAD-IN TO THE ACTUAL GAME AND IT'S AIM IS TO TELL THE PLAYER HOW TO PLAY THE GAME, ANY AVAILABLE OPTIONS AND P'HAPS PRESENT A NICE GRAPHIC OR TWO TO "WOW" THE USER INTO PLAYING. ╔N ADDATION, THE MAIN MUSICAL THEME CAN BE INTRODUCED HERE TO UNIFY THE GAME-PLAYING. ╘HE DISCUSSION BELOW DOES NOT TAKE INTO ACCOUNT COLOR BUT REST-ASSURED WE WILL BE USING VARYING COLORS IN THE TITLE SCREEN. ╘HE FORMAT FOR THE COLOR DATA WILL BE ALMOST IDENTICAL TO THE TITLE SCREEN FORMAT EXCEPT IT WILL BE STRUCTURED VIA THE FOLLOWING: .WORD ADDRESS .BYTE NUM_OF_CHARS TO PUT COLOR ($00= END OF DATA) .BYTE COLOR_VALUE ╘HE ROUTINE (COLOR'TEXT) CAN BE FOUND IN THE SOURCE LISTINGS AT THE END OF THIS ARTICLE. ┬ECAUSE OF THE SIMILARITY BETWEEN IT AND WRITE'TEXT IT IS NOT DISCUSSED IN THIS ARTICLE. ╘ITLE ╙CREEN ┬ACK╟ROUND ----------------------- ╘HE TITLE SCREEN ╔ ENVISONED AS A BORDERED SCREEN (USING THE NORMAL ├= CHARACTER SET - IE: ├= ┴,╙,┌,╪ ON THE KEYBOARD) WITH OUR BITMAP IN THE MIDDLE AND UNDER-NEATH IT A SHORT DESCRIPTION OF THE GAME AND GAME-PLAY INSTRUCTIONS. ╬OW THIS IS MY IDEA OF THE SCREEN LAYOUT (ROUGH DRAWING AS WE'RE NOT USING THE ACTUAL SCREEN DIMENSIONS): +-------------------------------------------------------------+ ▄ -╠╧╟╧ ----------------------------------------------------- ▄ ▄ --------------X 3 LINES------------------------------------ ▄ ▄ ----------------------------------------------------------- ▄ ▄ ▄ ▄ ╙PACE ╔NVASION ├64/128 ▄ ▄ ╨ROGRAMMING : ├RAIG ╘AYLOR ▄ ▄ ╟RAPHICS : ╨ASI ╧JALA ▄ ▄ ╙OUND : ???????????? ▄ ▄ ▄ ▄ ----------------------------------------------------------- ▄ ▄ ╘O ╨LAY: ▄ ▄ ╒SE JOYSTICK IN PORT 2, MOUSE IN PORT 1 OR KEYBOARD: ▄ ▄ ┴ - ╠EFT, ┌ - ╥IGHT ╙PACE - ╞IRE ▄ ▄ ╞1 - ╥ESTART ▄ ▄ ▄ +-------------------------------------------------------------+ ╘ITLE ╙CREEN ╞ORMATTING ----------------------- ╫E COME INTO A PROBLEM HERE -- THE SCREEN IS SOME 1000 CHARACTERS ON THE ├64, AND 2000 CHARACTERS FOR THE ├=128. ╔T WOULD BE EXTREMELY WASTEFUL TO STORE THAT MANY CHARACTERS IN MEMORY JUST TO REPRODUCE A TITLE SCREEN - AND MOST OF THEM CONSISTING OF SPACES AT THAT!! ╫HAT WE'LL DO IS TO JUST SPECIFY THE ADDRESS ON SCREEN, THE # OF CHARACTERS AND THEN LIST THE CHARACTERS. ╔T WILL BE SIMILAIR TO OUR CUSTOM CHARACTER TABLE DRIVER ABOVE BUT WILL BE DIFFERENT ENOUGH THAT A NEW ROUTINE IS WARRENTED. ╫E WILL HOWEVER USE THE TWO SUBROUTINES WRITEBYTE AND SETADRS THAT WERE DEVELOPED IN THE PREVIOUS ROUTINE. ╘HE DATA WILL LOOK LIKE THE FOLLOWING: .WORD ADDRESS .BYTE NUM_OF_CHARS ($00= END OF DATA) .ASCII "TEXT" .BYTE ADDRESS .... ETC.... AND WE'LL ENTER WITH .┴┘ CONTAINING THE ADDRESS OF THE TABLE. ╙O BASICALLY WE COME UP WITH THE FOLLOWING: ------------------------------------------------------------------------------- WRITE'TXT = * STA ZP1 ; SAVE .AY IN TABLE ADDRESS STY ZP1+1 LDY #$00 LOOP'W'TEXT = * JSR GET'BYTE ; SET ADDRESS. STA WRK JSR GET'BYTE STA WRK+1 JSR GET'BYTE ; GET # OF CHARS TO WRITE OUT. CMP #$00 BEQ + ; IF ZERO THEN EXIT. TAX JSR SETADRS ; SET ADDRESS TO WRK,WRK+1 - JSR GET'BYTE JSR WRITEBYTE ; WRITE OUT BYTE. DEX BNE - SEC BCS LOOP'W'TEXT ; THIS IS AN ABSOLUTE JUMP TO LOOP + RTS ; RETURN. ------------------------------------------------------------------------------- ╘HIS IS SIMILAIR TO OUR PREVIOUS ROUTINE, AND WAS IN FACT COPIED AND MODIFIED FROM THE PREVIOUS ROUTINE. ╓╔╔╔. ─EBUGGING --------- ╬OW, NOT ALL PROGRAMS ARE PERFECT, AND DURING THE DEVELOPMENT OF THIS PORTION OF THE GAME THERE WERE SEVERAL ERRORS FOUND. ╘RACING AN ERROR IN ═ACHINE/┴SSEMBLY-╠ANGUAGE IS LIKE TRYING TO FIND A GRAMMATICAL ERROR IN A LANGUAGE YOU DON'T KNOW. ;-) ┬UT SERIOUSLY, THERE ARE SEVERAL WAYS TO TRACK DOWN ERRORS IN YOUR CODE. 1 - ╘RY TRACING IT THROUGH BY HAND PLAYING "╫HAT IF ╔ WERE THE COMPUTER" AND FOLLOWING WHAT EACH REGISTER DOES. 2 - ┴RE YOU SWITCHING THE ╠O╚I ORDER OF VARIABLES? ╔E: IS IT LDA #< OR LDA #>?? 3 - ╙ET ┬╥╦ POINTS AND RUN THE PROGRAM / SUBROUTINE WITHIN A MACHINE LANGUAGE MONITOR AND MAKE SURE THE REGISTERS / MEMORY LOCATIONS CONTAIN THE VALUES THAT THEY SHOULD. ╔F NOT, FIND OUT WHY. 4 - ╘RY TO SIMPLIFY YOUR CODE IN TERMS OF PROGRAMMING EASE - ═AKE THE ASSEMBLER DO THE WORK FOR YOU - IT'S A LOT LESS LIKELY TO MAKE ERRORS THAN YOU ARE. 5 - ╘HINK LOGICALLY!!! 6 - ├HANGE SOMETHING AT RANDOM AND PRAY. ╔ CAN'T STRESS NUMBERS 3 AND 5 ENOUGH. ─URING THE WRITING OF THE INSTALL'CHAR ROUTINE THERE WERE NUMEROUS BUGS THAT WERE EVENTUALLY TRACKED DOWN BY SETTING A ┬╥╦ INSTRUCTION FURTHER ALONG IN THE CODE AND SEEING EXACTLY WHAT THE REGISTER / MEMORY LOCATIONS WERE. ┴LSO THE USE OF TEMPORARY LOAD AND STORE INSTRUCTIONS INTO "SAFE" REGIONS OF MEMORY HELPED ME MONITOR WHAT SOME OF THE VALUES WERE. ╞OR EXAMPLE, AT ONE POINT ╔ HAD A SECTION OF CODE SIMILAIR TO THE FOLLOWING: CLC LDA VALUE ADC DATA BNE + INC DATA+1 + [.... ] ┴ND IT'S PURPOSE WAS TO ADD VALUE TO DATA. ╬OW ╔'VE FOUND SIMPLE ERRORS ARE USUALLY FOUND LAST, AFTER COMPLEX ERRORS. ┴ND NOT UNTIL A SET A BREAK POINT LIKE: CLC LDA VALUE ADC DATA <-----═ISSING ╔NSTRUCTION AFTER HERE-------------+ BNE + ▄ INC DATA+1 ▄ + ┬╥╦ ▄ [.... ] ▄ ▄ DID ╔ ACTUALLY FIGURE OUT THAT ╔ WAS MISSING THE ╙╘┴ ─┴╘┴ INSTRUCTION --+ ╙O, WHEN WRITING, MODIFYING, AND TRYING TO DEBUG CODE TRY TO TAKE YOUR TIME AND ISOLATE EVERY POSSIBLE PROBLEM. ┴LSO DON'T BE AFRAID TO STOP THE CODE MID-STREAM AS IN THE ABOVE WITH USE OF THE ┬╥╦. ┘OU CAN ALWAYS REMOVE IT (AND PROBAHLY SHOULD) IN THE FINAL CODE AND IT SERVES AS A VERY VALUABLE DEBUGGING TOOL WITH THE AID OF A MACHINE-LANGUAGE MONITOR. ╔╪. ═EMORY ═AP ├ONSIDERATIONS ------------------------- ┬EFORE YOU START A PROGRAM IT'S A GOOD IDEA TO CONSIDER WHERE IN MEMORY YOU WILL HAVE EVERYTHING. ╬OW WE'VE ALREADY STARTED SOME OF THE PROGRAM ABOVE AND JUST BLINDLY PICKED NUMBERS AT RANDOM IT SEEMED LIKE $3000 FOR THE CHARACTER SET FOR THE ├=64 ETC... ╫E DIDN'T - ╔'M INTRODUCING THE ═EMORY ═AP ├ONSIDERATIONS HERE TO SHOW THE EXAMPLE OF WHAT IF WE DIDN'T THINK ABOUT HOW MEMORY WAS GOING TO BE ORGANIZED. ╘HE ├=64 ONLY HAS 64K OF MEMORY OF WHICH TYPICALLY THE RANGE $0800-$A000 IS AVAILABLE AND $C000-$CFFF IS ALSO. ╔F WE HAD BLINDLY PICKED NUMBERS ALL OVER THE PLACE TO STORE OUR CODE THEN WE WOULD HAVE A DISORGANIZED PROGRAM THAT WOULD MOST LIKELY ACCIDENTALLY USE ONE SUBROUTINES STORAGE AS TEMPORARY DATA FOR ANOTHER. ╔T'S LIKE SHOOTING RANDOMLY IN ╠ASER ╘AG NOT CHECKING TO SEE IF THERE IS A TARGET THERE OR NOT FIRST... ╘HE END RESULT: ├HAOS. ├URRENTLY WE'RE NOT FOLLOWING THE RULE FOR "TEMPORARY VARIABLES" BUT AS WE GRADUALLY FADE OUT OF THE NORMAL ├-64/128 DEFAULT MODE AND WRITE OUR OWN ROUTINES / INTERRUPT HANDLERS WE'LL SWITCH THINGS OVER. ┴LSO, ON THE ├=128 INSTEAD OF USING ┬ANK 0 WITH THE ╔/╧ BLOCK ENABLED WE'RE CURRENTLY USING THE ┬┴╬╦ 15 CONFIGURATION AS THE PROGRAM DOESN'T EXTEND PAST $4000 YET ($0000-$4000 IS COMMON MEMORY IN THE NORMAL ├=128 CONFIGUARTION). 64 ├ONSIDERATIONS ----------------- ╘HE 64 WILL HAVE FREE MEMORY IN THE FOLLOWING AREAS: $0800-$A000, AND $C000-$CFFF. ╚OWEVER, IF WE DISABLE THE ┬ASIC ╥OM WE CAN HAVE THE WHOLE AREA FROM $0800-$CFFF FREE FOR OUR PROGRAM. ┬ECAUSE WE DON'T NEED THE ┬ASIC ╥OM WE WILL DO JUST THAT (IN THE LISTING NOW WE CURRENTLY WON'T BUT IT WILL BE DONE IN A FUTURE ISSUE). ╘HEREFORE HAVING THE CHARACTER SET AT $3000-$5000, THE MUSIC DATA AT $5000-$8000, THE PROGRAM WILL HAVE THE AREA FREE FROM $8000-$CFFF. $0800-$3000 WILL BE AVAILABLE IF NEEDED FOR ROUTINES WHO NEED TEMPORARY STORAGE. ╘EMPORARY ╙TORAGE IS GOING TO BE DEFINED AS FOLLOWS. ┼ACH ROUTINE THAT NEEDS TEMPORARY STORAGE WILL BE ASSIGNED A "LEVEL" NUMBER. ╘HE LOWER LEVELS WILL BE ASSIGNED LEVEL 1 ON UP TO LEVEL 3. ╘HE RANGE $0800-$3000 WILL BE BROKEN DOWN INTO THE FOLLOWING SUB-RANGES. ╠EVEL 1: $0800-$1000 ╠EVEL 2: $1000-$1800 ╠EVEL 3: $1800-$3000 ╘HIS WAY WHEN WRITING THE SUB-ROUTINES WE CAN BE ASSURED THAT A SECTION OF MEMORY IS NOT OVERWRITTEN BY A SUBROUTINE WE CALL. ╫HEN WE ACTUALLY START PROGRAMMING WE'LL DECIDE WHERE IN EACH SUB-RANGE THE ROUTINE WILL HAVE ACCESS TO. 128 ├ONSIDERATIONS ------------------ ╘HE 128 HAS TWO "BANKS" OF 64K EACH. ╬ORMALLY FOR LARGE PROGRAMS WE WOULD THINK ABOUT USING BOTH BANKS - (FROM THE IDEA: ╚EY! - ╫E GOT IT, WHY NOT FLAUNT IT?) BUT WE WON'T BE USING BOTH BANKS. ╞REE MEMORY ON THE ├128 TYPICALLY CONSISTS OF THE RANGE $0400-$09FF (WHERE WE'LL BE OVERWRITING THE 40 COLUMN SCREEN (WHICH WE'RE GONNA BLANK ANYWAY) AND THE ┬ASIC RUN-TIME STACK.) ┴LSO THE AREA FROM $0B00-$0FFF IS FREE (OVERWRITING THE TAPE AREA, THE RS-232 BUFFERS,L AND THE SPRITE DEFINITION AREA). ┴LSO $1300-$CFFF WILL BE FREE. ╬OW, THE ├=128 HAS DIFFERENT MEMORY MAPS IT CAN CONFIGURE ITSELF TO - ┬ANK 15 IS THE STANDARD MODE UNDER MOST BASIC PROGRAMS AND ALLOWS THE PROGRAMMER TO DIRECTLY "SYS" TO CALLS. ╘HE ══╒ (MEMORY MANAGEMENT UNIT - THE CHIP THAT DOES EVERYTHING) SEES MEMORY IN A SLIGHTLY DIFFERANT WAY THAN FROM BASIC. ╫E'LL COVER IT IN MORE DETAIL WHEN WE EXAMINE THE MEM_INIT ROUTINE. ╞OR NOW, WE'RE JUST GONNA SET UP IN THE PROGRAM AND NOT IN THE CODING SEGMENTS. ╘HE EXPLANATION OF WHAT WE'RE DOING WILL BE "REVEALED" IN A FUTURE ISSUE. ╫E WILL USE ┬ANK 0 OF MEMORY AND FROM $1300+ WILL BE THE PROGRAM. ╘HE RANGES OF $0400-$09FF AND $0B00-$0FFF WILL BE USED IN A SIMILAIR MANNAR AS THE ├64 RANGES WERE FOR ╘EMPORARY ╙TORAGE. ╫E WILL ALSO HAVE THE ╔/╧ SECTION FROM $D000-$DFFF SWAPPED IN. ╘HIS IS NOT A STANDARD "BASIC ┬┴╬╦ #" BUT WHEN WE COVER THE INIT'MEMORY ROUTINE WE'LL SEE HOW WE CAN DO THIS. ═USIC DATA WILL BE FROM $A000-$D000. ╪. ╠OOKING ╞ORWARD / ┬ACK ---------------------- ╚OPEFULLY THROUGH THE LISTING AND THE DISCUSSION OF THE ROUTINES YOU HAVE STARTED TO UNDERSTAND THE BASIC CONCEPT OF PROGRAMMING: BREAKING DOWN PROBLEMS INTO SMALLER SOLVABLE STEPS. ╘RY LOOKING BACK OVER THE CODE ASKING YOURSELF WHY THAT INSTRUCTION IS THERE. ╫HAT WOULD HAPPEN IF YOU SWITCHED THE ORDER? ╔S THERE AN EASIER, BETTER WAY TO DO THE SAME THING? ╫HY? ┬ETTER YET, HOW? ┼XAMINE THE CODE, MESS WITH IT, MUCK IT UP SO IT DOESN'T WORK AND THEN FIGURE OUT EXACTLY WHY. ╘HE ONLY WAY TO LEARN IS BY EXPERIMENTATION. (┬╘╫, MUCK UP A _COPY_ OF IT - NOT THE ORIGINAL ... *GRINS*) ╘AKE A LOOK AT THE DIFFERENT SECTIONS OF CODE AND ANALYZE THEM TO SEE HOW THEY DO WHAT THEY DO. ╘AKE A LOOK AT HOW THE CODE WAS ORGANIZED IN TERMS OF SIMPLIFICATION. ╘RACE THROUGH EACH SUBROUTINE SO THAT YOU'RE ABLE TO KNOW WHAT THE RETURN VALUES WILL BE. ╔N OTHER WORDS: ╙TUDY, ╙TUDY, ╙TUDY!! ╔'M IN SCHOOL AND SO ╔ KNOW ╔ JUST USED THE DREADED '╙' WORD BUT THAT'S WHAT YOU'RE GOING TO HAVE TO DO IF YOU'RE INTERESTED IN LEARNING 65XX/85XX MACHINE LANGUAGE. ╘HE ONLY WAY TO LEARN IT (EASILY) IS TO STUDY OTHER PEOPLE'S CODE AND TRY TO UNDERSTAND WHY THEY DID WHAT THEY DID. ╬EXT TIME WE WILL TAKE A LOOK AT THE INPUT ROUTINES FOR THE MOUSE, JOYSTICK AND KEYBOARD SCANNING. ╔N ADDITION WE WILL ALSO ALLOW THE PLAYER TO MOVE THE SHIP AROUND ON THE SCREEN TO TEST THE INPUT DRIVERS. ╔N ADDATION, ╔ AM STILL LOOKING FOR AN INDIVIDUAL TO HELP WITH MUSIC AND SOUND COMPOSITION FOR THIS PROGRAM. ┴ KNOWLEDGE OF THE ╙╔─ CHIP AND PROGRAMMING IS HELPFUL BUT NOT REQUIRED. ╔F YOU'RE WILLING TO HELP THEN PLEASE EMAIL ME AT DUCK@PEMBVAX1.PEMBROKE.EDU ╪╔. ╠ISTINGS -------- ┬ECAUSE OF THE ENORMITY OF THE PROGRAM LISTING (SOME 1,500+ LINES) IT WILL NOT BE LISTED IN THIS ARTICLE BUT WILL INSTEAD BE AVAILABLE VIA ANONYMOUS FTP AT CCOSUN.CALTECH.EDU UNDER PUB/RKNOP/╚┴├╦╔╬╟.═┴╟ AS INVAS1.SFX. ╞OR THOSE OF YOU ON THE MAILING LIST WHO WOULD LIKE TO RECIEVE IT, A ═AIL- ╙ERVER WILL BE SET UP SOON TO HANDLE REQUESTS AND INFORMATION WILL BE SENT TO YOU CONCERNING INFORMATION ABOUT USING IT AS SOON AS IT'S COMPLETED. ╔N THE INVASION1.SFX FILE THERE ARE THE FOLLOWING FILES: INVASION.SRC - THE MAIN FILE GRAPHICS.SRC - HANDLES ALL GRAPHICS ROUTINES LOGO.DAT - CUSTOM CHARACTER LOGO CHARS64.DAT - ALIEN CUSTOM CHARACTERS FOR ├=64 CHARS128.DAT - ALIEN CUSTOM CHARACTERS FOR ├=128 TITLETXT.DAT - TEXT DATA FOR TITLE SCREEN TITLECOL.DAT - COLOR DATA FOR TITLE SCREEN INVASION-128 - EXECUTABLE VERSION OF ╙PACE ╔NVASION SO FAR FOR ├=128 INVASION-64 - EXECUTABLE VERSION OF ╙PACE ╔NVASION SO FAR FOR ├=64 ╬OTE: ╞OR THE ├OMMODORE 128 IT'S RECOMMENDED THAT YOU DO A RUN/STOP-RESTORE AND THEN A "┬┴╬╦15:╙┘╙7168" TO EXECUTE THE PROGRAM. ╞OR THE ├OMMODORE 64 IT'S RECOMMENDED THE BORDER BE CHANGED VIA: "╨╧╦┼53280,0:╨╧╦┼53281,0:╙┘╙ 32768" TO RUN THE PROGRAM. ============================================================================== ╘HE ─EMO ├ORNER: ╞╠╔ - MORE COLOR TO THE SCREEN BY ╨ASI '┴LBERT' ╧JALA (PO87553@CS.TUT.FI OR ALBERT@CC.TUT.FI) ╫RITTEN ON 16-═AY-91 ╘RANSLATION 01-╩UN-92 (┴LL TIMINGS ARE IN ╨┴╠, ALTHO THE PRINCIPLES WILL APPLY TO ╬╘╙├ TOO) ┴LL OF US HAVE HEARD COMPLAINTS ABOUT THE COLOR CONSTRAINTS ON ├64. ╧NE 8X8 PIXEL CHARACTER POSITION MAY ONLY CARRY FOUR DIFFERENT COLORS. ╞╠╔ PICTURE CAN HAVE ALL OF THE 16 COLORS IN ONE CHAR POSITION. ╫HAT THEN IS THIS ╞╠╔ AND HOW IT IS DONE ? ╔N THE NORMAL MULTICOLOR MODE CAN ONE CHARACTER POSITION (4X8 PIXELS) HAVE ONLY FOUR DIFFERENT COLORS AND ONE OF THEM IS THE COMMON BACKGROUND COLOR. ├OLOR CODES ARE STORED IN HALF BYTES (NYBBLES) TO THE VIDEO MATRIX MEMORY (ANYWHERE VIDEO MATRIX POINTER POINTS AT, NORMALLY $0400) AND TO THE COLOR MEMORY ($─800-$─┬╞╞). ╔N MULTICOLOR MODE THE COLOR OF EACH PIXEL IS DETERMINED BY TWO BITS IN THE GRAPHICS MEMORY. ┬IT PAIR 11 WILL REFER TO COLOR MEMORY, BACKGROUND COLOR IS THE COLOR FOR BIT PAIR 00, AND VIDEO MATRIX WILL DEFINE THE COLORS FOR BIT PAIRS 01 AND 10. _╫HAT HAPPENS IN THE ╓╔├ ?_ ╓╔├ (╓IDEO ╔NTERFACE ├ONTROLLER) FETCHES COLOR INFORMATION FROM MEMORY ON EACH BAD LINE. ╘HIS WILL STEAL TIME FROM PROCESSOR, BECAUSE ╓╔├ NEEDS TO USE PROCESSOR'S BUS CYCLES. ┬AD LINE IS A CURSE IN THE ├64 WORLD. ╞ORTUNATELY ╓╔├'S DATA BUS IS 12 BITS WIDE AND SO THE COLOR DATA FETCH FOR EACH CHARACTER POSITION WILL TAKE ONLY ONE BUS CYCLE. ├OLOR MEMORY IS PHYSICALLY WIRED TO THE ╓╔├ DATABUS LINES ─8-─11. ╚OW DOES ╓╔├ KNOW WHERE TO FETCH THE GRAPHICAL INFORMATION ? ╙OME OF YOU KNOW THE MYSTICAL FORMULAS NEEDED TO MESS WITH THE PIXELS IN THE HIRES SCREEN. ╚OW ARE THESE FUNCTIONS OBTAINED ? ┴RE THEY JUST MAGIC ? ╬O, THERE ARE SOME INTERNAL COUNTERS IN ╓╔├. ╘HEY ALWAYS POINT TO THE RIGHT PLACE IN GRAFIX MEMORY AND THE ADDRESS IS DETERMINED LIKE THIS: ┴13 ┴12 ┴11 ┴10 ┴9 ┴8 ┴7 ┴6 ┴5 ┴4 ┴3 ┴2 ┴1 ┴0 ├┬13 ╓├9 ╓├8 ╓├7 ╓├6 ╓├5 ╓├4 ╓├3 ╓├2 ╓├1 ╓├0 ╥├2 ╥├1 ╥├0 ┴DDRESS BITS ┴15 AND ┴14 CHANGE ACCORDING TO THE SELECTED VIDEO BANK. ┴DDRESS BIT ┴13 IS ├┬13, WHICH MAY BE FOUND IN ╓╔├ REGISTER $18. ╔T SELECTS THE RIGHT SIDE OF THE VIDEO BANK TO BE THE BITMAP MEMORY. ╫ITH THESE BITS YOU CAN SET THE BITMAP TO EIGHT DIFFERENT PLACES IN MEMORY. ╚OWEVER, SOME OF THEM ARE USELESS BECAUSE OF THE CHARACTER ╥╧═ IMAGES AND ZERO PAGE/STACK. ╥EST OF THE BITS COME FROM THE INTERNAL COUNTERS. ╓├9-╓├0 (╓IDEO ├OUNTER) FORMS THE ADDRESS BITS 12-3. ╘HE COUNTER ROLLS THROUGH ALL 1000 CHARACTER POSITIONS, 0-39 ON THE FIRST EIGHT LINES, 40-79 ON THE SECOND EIGHT LINES AND SO ON. ╘HE LOWEST THREE BITS COME FROM THE ROW COUNTER, ╥├2-╥├0. ╘HIS IS ANOTHER ╓╔├ COUNTER AND IT COUNTS THE SCAN LINES FROM ZERO TO SEVEN. _┴ SOFTWARE GRAPHICS MODE - ╞╠╔_ ╓╔├ WILL SYSTEMATICALLY GO THROUGH EVERY BYTE IN THE BITMAP MEMORY, BUT HOW DOES IT KNOW WHERE AND WHEN TO GET THE COLOR INFORMATION ? ╘HIS IS WHERE THE MAIN PRINCIPLE OF ╞╠╔ (╞LEXIBLE ╠INE ╔NTERPRETATION) LIES. ├OLOR DATA IS FETCHED (AND THIS MEANS IT IS A BAD LINE), WHEN THE LINE COUNTER MATCHES WITH THE VERTICAL SCROLL REGISTER. ╓├9-╓├0 DEFINES WHERE THE COLOR DATA IS INSIDE THE VIDEO MATRIX AND COLOR MEMORY. ╔F WE CHANGE THE VERTICAL SCROLL REGISTER, WE CAN FOOL ╓╔├ TO THINK THAT EVERY LINE IS A BAD LINE, SO IT WILL FETCH THE COLOR INFORMATION ON EVERY LINE TOO. ┬ECAUSE ╓╔├ WILL FETCH THE COLORS CONTINUOSLY, WE CAN GET INDEPENDENT COLORS ON EACH SCAN LINE. ╫E JUST HAVE TO CHANGE COLORS AND ╓╔├ WILL HANDLE THE REST. ╒NFORTUNATELY THE RESULT IS THE LOSS OF 40 PROCESSOR CYCLES PER LINE (SEE THE ═ISSING ├YCLES ARTICLE FOR MORE INFORMATION ABOUT ╓╔├ STEALING CYCLES). _─OING IT IN PRACTICE_ ╔N PRACTICE THERE IS NO TIME TO CHANGE COLOR MEMORY, BUT IN MULTICOLOR MODE ╓╔├ USES VIDEO MATRIX FOR COLOR INFORMATION TOO. ╫E HAVE JUST ENOUGH TIME TO CHANGE THE VIDEO MATRIX POINTER, $─018. ╬OW ╓╔├ WILL SEE A DIFFERENT VIDEO MATRIX ON EACH SCAN LINE, DIFFERENT BLOCK OF MEMORY. ╫ITH THE FOUR UPPER BITS IN THE REGISTER WE SELECT ONE OF THE 16 VIDEO MEMORIES IN THE VIDEO BANK. ╩UST REMEMBER THAT THE REGISTER ALSO SELECTS THE POSITION OF THE GRAPHICS MEMORY (BITMAP) INSIDE THE VIDEO BANK. ┬ECAUSE WE HAVE TO KEEP THE BITMAP IN THE SAME VIDEO BANK, WE ONLY HAVE HALF OF THE BANK FREE FOR VIDEO MATRICES. ╞ORTUNATELY, THAT'S ALL WE NEED TO GET INDIVIDUAL MULTICOLOR COLORS FOR EACH LINE AND CHARACTER POSITION. ╓╔├ WILL FETCH THE COLOR DATA FROM THE EIGHT VIDEO MATRICES AND THEN IT WILL ROLL ON TO THE NEXT 40 BYTES. ┴FTER EIGHT LINES AND MATRICES WE WILL SELECT THE FIRST VIDEO MATRIX AGAIN. (╙EE PICTURE 1) ╒SUALLY IT IS NOT NECASSARY TO USE THE WHOLE SCREEN FOR A ╞╠╔ PICTURE, ESPECIALLY IF YOU WANT TO HAVE A SCROLLER OR SOME OTHER EFFECTS. ┘OU JUST HAVE TO MAKE SURE THAT ╓╔├ IS FOOLABLE IN THE USUAL WAY. ╘HE TIMING IS ALSO VERY IMPORTANT, EVEN ONE CYCLE VARIATIONS IN THE ROUTINE ENTRY ARE NOT ALLOWED. ╘HERE IS MANY WAYS TO DO THE SYNCHRONIZATION. ╧NE WAY IS TO USE A SPRITE, AS IN THE PREVIOUS ARTICLE. (╙EE ├= ╚ACKING, ╓OL. 1, ╔SS. 3, ╘HE ─EMO ├ORNER: ═ISSING ├YCLES). _╬OT MUCH TIME_ ┬ECAUSE A BAD LINE WILL STEAL 40 CYCLES, THERE IS ONLY 23 CYCLES LEFT ON EACH SCAN LINE. ╔T IS ENOUGH FOR CHANGING THE VIDEO MATRIX AND BACKGROUD COLOR. ╘HERE IS NOT A MOMENT TO LOSE, BECAUSE YOU MUST CHANGE THE VERTICAL SCROLL REGISTER, VIDEO MATRIX POINTER AND THE BACKGROUND COLOR. ╘HIS IS WHY YOU CAN'T HAVE SPRITES IN FRONT OF A ╞╠╔ PICTURE. ╫ITH ╞╠╔ WE GET TWO SELECTABLE COLORS FOR EACH CHARACTER POSITION AND LINE, EACH SCAN LINE CAN HAVE IT'S OWN BACKGROUND COLOR AND EACH CHARACTER POSITION STILL HAS ITS OWN CHARACTER COLOR FROM COLOR MEMORY. ╔N THEORY EACH CHARACTER POSITION COULD HAVE 25 DIFFERENT COLORS, UNFORTUNATELY ╓╔├ ONLY HAS 16. _┴ LITTLE FEATURE_ ╓╔├ DOES NOT LIKE IT WHEN WE CHANGE THE VERTICAL SCROLL REGISTER ($─011), AND IS A BIT ANNOYED. ╔T 'SEES' CODE 255 (LIGHT GRAY) IN VIDEO MATRIX AND 9 (BROWN) IN THE COLOR MEMORY INSTEAD OF THE CORRECT VALUES STORED THERE. ┴CTUALLY THE COLOR VALUE SEEMS TO BE THE LOWER NYBBLE OF THE DATA BYTE CURRENTLY ON THE DATA BUS (ACCESSED BY THE PROCESSOR (╠─┴#=$┴9)). ╒NFORTUNATELY THERE IS NO CHANCE TO DO THE REGISTER CHANGE IN THE BORDER AND THUS THE THREE LEFTMOST CHARACTER COLUMNS ARE A BIT USELESS, BECAUSE THE COLORS ARE FIXED. ╚OWEVER, THIS DOESN'T MEAN THAT YOU CAN'T USE THOSE THREE COLUMNS. ╞╠╔ EDITORS MAY NOT SUPPORT THE FIXED COLORS THOUGH, SO IT MAY BE HARD TO USE THEM. _╫HAT TO DO WITH ╞╠╔ ?_ ┬ECAUSE ╞╠╔ WILL EAT UP ALL THE AVAILABLE PROCESSOR TIME (NO ├OPPER :-), IT IS NOT SUITABLE FOR ANY ACTION-GAMES. ┼ACH ╞╠╔ PICTURE TAKES ABOUT 17 K┬ OF MEMORY: NOT SO MANY PICTURES FIT ON ONE FLOPPY. ╙O, THE ONLY PLACE FOR ╞╠╔ IS DEMOS, INTROS, BOARD-TYPE GAMES AND MAYBE A ╟╔╞ VIEWER.. -------------------------------------------------------------------------- ╨ICTURE 1: ╞ROM WHICH MATRIX ╓╔├ FETCHES THE MULTICOLOR VALUES _ ___________________________________________________________ ▄ ... ▄ ═ATRIX0 ▄ ═ATRIX0 ▄ ═ATRIX0 ▄ ▄ , .▄____3__________▄____4__________▄____5__________▄ ... ▄ ╒ .▄ ═ATRIX1 ▄ ═ATRIX1 ▄ ═ATRIX1 ▄ ▄ S .▄____3__________▄____4__________▄____5__________▄ . ▄├HAR E ▄ ═ATRIX2 ▄ ═ATRIX2 ▄ ═ATRIX2 ▄ . ▄╠INE L ▄____3__________▄____4__________▄____5__________▄ . ▄┌ERO E ▄ ═ATRIX3 ▄ ═ATRIX3 ▄ ═ATRIX3 ▄ ▄ S ▄____3__________▄____4__________▄____5__________▄ ▄ S, ▄ ═ATRIX4 ▄ ═ATRIX4 ▄ ═ATRIX4 ▄ ▄ ▄____3__________▄____4__________▄____5__________▄ ▄ C ▄ ═ATRIX5 ▄ ═ATRIX5 ▄ ═ATRIX5 ▄ ▄ O ▄____3__________▄____4__________▄____5__________▄ ▄ L ▄ ═ATRIX6 ▄ ═ATRIX6 ▄ ═ATRIX6 ▄ ▄ U ▄____3__________▄____4__________▄____5__________▄ ▄ M ▄ ═ATRIX7 ▄ ═ATRIX7 ▄ ═ATRIX7 ▄ ▄_ N ▄____3__________▄____4__________▄____5__________▄ S ▄ ═ATRIX0 ▄ ═ATRIX0 ▄ ═ATRIX0 ▄ ▄___43__________▄___44__________▄___45__________▄ ▄ ═ATRIX1 ▄ ═ATRIX1 ▄ ═ATRIX1 ▄ ▄___43__________▄___44__________▄___45__________▄ ▄ ▄ ... ▄ . ▄ . ▄ . -------------------------------------------------------------------------- _┴DDITIONAL READING_ ╔F YOU HAVE AN ┴MIGA YOU MIGHT WANT TO GET YOUR HANDS INTO MY CONVERSION PROGRAMS IN ├64╟╞╪1.LHA. ╘HE PACKET ALSO INCLUDES ╞╠╔ VIEWER FOR ╨┴╠ ├64'S AND SOME DOCUMENTATION ABOUT THE ╞╠╔ FILE FORMAT. ╔T ALSO HAS THE SAME UTILITIES FOR ╦OALA FORMAT PICTURES. ┴VAILABLE FROM: CWAVES.STFX.CA NIC.FUNET.FI:/PUB/AMIGA/GRAPHICS/APPLICATIONS/CONVERT ├64╟╞╪.DOC ├64╟FX1.0 ┴ ├64 GRAFIX FORMAT CONVERSION PACKAGE )1991,1992 ╨ASI '┴LBERT' ╧JALA ┼-MAIL: PO87553@CS.TUT.FI ALBERT@CC.TUT.FI ╘HIS PACKAGE CONTAINS PROGRAMS WHICH ARE USED TO CONVERT PORTABLE PIXMAP (PPM) FILES TO ├64 GRAPHICS FORMATS (╞╠╔ AND KOALA) UNDER ┴MIGA╧╙. ╘HE PACKAGE INCLUDES ├ SOURCE CODES FOR THE PROGRAMS, SO IT IS POSSIBLE TO PORT THE PROGRAMS TO ANOTHER ENVIRONMENT. ├64╟╞╪1.1 INCLUDES ╒NIX-COMPILABLE SOURCES. ╔N ADDITION TO THIS PACKAGE YOU NEED E.G. ╨┬═╨LUS TO CONVERT ┴MIGA ILBM FILES TO PPM FIRST. ┴ND OF COURSE SOME WAY TO TRANSFER FILES BETWEEN THE MACHINES. ============================================================================= ╥╙-232 ├ONVERTER BY ╫ARREN ╘USTIN (WARREN@COL.HP.COM) ╘HIS ARTICLE PRESENTS A WAY TO INTERFACE FROM THE ├= RS232 HARDWARE BEHIND THE USER PORT TO A STANDARD 25PIN FEMALE RS232 CONNECTOR USING ONLY ONE ╔├ AND A FEW CAPACITORS. ╔T IS NOT A ╒┴╥╘ OR A ╙╫╔╞╘╠╔╬╦ TYPE INTERFACE WHICH TAKE PLACE OF THE INTERNAL ├= RS232 CIRCUITRY, BUT A SIMPLE LEVEL SHIFTING INTERFACE THAT USES THE INTERNAL RS232 ROUTINES AND TRANSLATES THE USER PORT LEVELS TO RS232 LEVELS. ╘HEREFORE YOU CAN ONLY GET UPTO 2400BAUD/9600BAUD (├=64/├=128) WITH THIS DESIGN. ╘HE "OLD" WAY TO DO THIS WAS TO USED ═├1488 AND ═├1489 PARTS (A LINE DRIVER AND LINE RECEIVER), HOWEVER THESE REQUIRED A NEGATIVE SUPPLY TO INTERFACE PROPERLY. ╘HE USER PORT ONLY SUPPLIES +5VOLTS, HENCE THIS PRESENTS A PROBLEM. ╘HERE HAS BEEN SUCCESS USING THESE PARTS OR DISCRETE TRANSISTORS AND RESISTORS SINCE MANY MODEMS ARE SOMEWHAT FRIENDLY AND SEEM TO WORK EVEN THOUGH THE LEVELS WERE MARGINAL. ┴LSO, SOME SIGNALS WERE NOT USED, ALLOWING FOR POTENTIAL PROBLEMS. ┴NOTHER WAY TO SOLVE THIS PROBLEM WAS TO BUY A $25-30 INTERFACE. ╔F YOU CAN FIND THE ╔├ BELOW, YOU HAVE ANOTHER CHOICE THAT IS RELATIVELY INEXPENSIVE. ╘HE ╠╘1133 IS BASICALLY THE ═├1488 AND 1489 PUT TOGETHER INTO ONE PART WITH AN INTERNAL CHARGE PUMP SCHEME THAT ALLOWS THE INTERNAL DRIVERS TO OUTPUT +5 AND -5 VOLTS TO THE RS232 CONNECTOR. ╔T ALSO HAS ENOUGH DRIVERS AND RECEIVERS TO HANDLE ALL OF THE SIGNALS THAT THE ├= USES FOR RS232. ╙O WITH THIS ╔├, 5 CAPACITORS AND THE TWO CONNECTORS (USER PORT AND RS232) YOU CAN BUILD YOUR OWN INTERFACE TO THE STANDARD 25 PIN MODEM CABLE. ╚ERE ARE THE PLANS FOR AN ╒SER PORT ╘╧ ╥╙232 CONNECTOR USING JUST ╧╬┼ ╔├ AND 4 CAPACITORS. ╔T USES A ╠INEAR ╘ECHNOLOGY ╠╘1133 BUFFER THAT HAS 3 ╥╙232 DRIVERS AND 5 RECEIVERS. ╔T HAS WORKED FOR ME WITH NO PROBLEMS AND TAKES A MINIMUM AMOUT OF WIRING TO GET TO WORK. ═Y BOARD IS ONLY THE WIDTH OF THE USER PORT AND ABOUT 1.5 INCHES DEEP IN SIZE. ╨ARTS LIST: ---------- ╠╘1133├╬ PLASTIC DIP OR ╠╘1133├╩ CERAMIC DIP ╥╙232 DRIVER FROM ╠INEAR ╘ECHNOLOGIES (╔T TAKES 27M┴ MAX (17M┴ TYPICAL) SO IS WELL BELOW THE 100M┴ LIMIT OF THE USER PORT) ─RIVER ╔N PINS (15,19,21) ╘╘╠/├═╧╙ COMPATIBLE. ╒NUSED INPUTS ▄ ▄ ▄ SHOULD BE TIED TO +5V. ─RIVER ╧UT PINS (11, 7, 5) ╥╙232 COMPATIBLE. ╙HORT CIRCUIT PROTECTED FROM -30V TO +30V. ╥ECEIVER ╔N PINS (6, 8, 9, 10,12) ┴CCEPT ╥╙232 LEVELS (+-30V) ▄ ▄ ▄ ▄ ▄ AND HAVE 0.4V OF HYSTERESIS TO ▄ ▄ ▄ ▄ ▄ PROVIDE NOISE IMMUNITY. ╥ECEIVER ╧UT PINS (20,18,17,16,14) ╘╘╠/├═╧╙ OUTPUTS. ╬╧╘┼: ╠INES ABOVE INDICATE WHICH INPUTS GO WITH WHICH OUTPUTS, AND THE PAIRS CAN BE INTERCHANGED FREELY. ╔ CONNECTED THEM AS DESCRIBED BELOW BECAUSE THE WIRING WORKED OUT THE BEST FOR ME. 4 - >= 1U╞ CAPACITORS ╒SED TO GENERATE ╥╙232 VOLTAGES BY A CHARGE PUMP TECHNIQUE INSIDE ╔├ 1 1U╞ CAPACITOR ╘O BYPASS THE 5VOLT SUPPLY FOR NOISE REJECTION. 1 ╒SER PORT FEMALE CONNECTOR. (╔ JUST DUG THIS UP, ╔'M NOT SURE WHERE THESE CAN BE FOUND, ╔ THINK IT IS 0.159" SPACING, 24PIN. 1 ╥╙232 25PIN FEMALE CONNECTOR. ├AN BE FOUND AT ╥-╙HACK ╙OME SORT OF .1" SPACING PROTO BOARD ├ONNECTIONS: ----------- ╒SER PORT CONNECTOR (╠OOKING INTO THE ├64 OR ├128) 1 2 3 4 5 6 7 8 9 10 11 12 ------------------------------------ ▄╪╪╪╪╪╪╪╪╪╪╪╪╪╪╪╪╪╪╪╪╪╪╪╪╪╪╪╪╪╪╪╪╪╪▄ ------------------------------------ ┴ ┬ ├ ─ ┼ ╞ ╚ ╩ ╦ ╠ ═ ╬ ╟ROUND & ╨OWER: -------------- ╨INS 1, ┴, 12, ╬ TO ╟ROUND OF BOARD. ╠╘1133 PIN 2 TO PIN 2 OF ╒SER PORT CONNECTOR (+5 VOLTS) 1U╞ CAPACITOR BETWEEN PIN2 AND GROUND (BYPASS CAP) ╠╘1133 PIN 13 TO ╟ROUND. ╥╙232 CONNECTOR PINS 7 & 1 TO ╟ROUND. ╠╘1133 CAPACITORS: 1U╞ FROM PIN 1 (╓+) TO GROUND (╔F POLARIZED (ELECTROLYTIC) + SIDE TO PIN 1) 1U╞ FROM PIN 24 (╓-) TO GROUND (┴S ABOVE BUT + SIDE TO GROUND) 1U╞ FROM PIN 3 (├1+) TO PIN 4 (├1-) (┴GAIN IF POLARIZED, + SIDE TO PIN 3) 1U╞ FROM PIN 22 (├2+) TO PIN 23 (├2-) (┴GAIN IF POLARIZED, + SIDE TO PIN 22) ├OMMODORE SIDE ╥╙232 SIDE ╒SER PORT ╙IGNAL ╨IN OF ╙IGNAL ╨IN OF ╥╙232 PIN NAME ╠╘1133 DIRECTION ╠╘1133 CONNECTOR --------- ------ ------ --------- ------ --------- ┬ ╞╠┴╟2 ─IN 20 <-- 6 3 ├ ╨┬0 ─IN ALSO CONNECT TO ABOVE PIN 20 ─ ╨┬1 ╥╘╙ 21 --> 5 4 ┼ ╨┬2 ─╘╥ 19 <-- 7 20 ╞ ╨┬3 ╥╔ 18 --> 8 22 ╚ ╨┬4 ─├─ 17 --> 9 8 ╩ ╨┬5 ╬OT USED ╦ ╨┬6 ├╘╙ 16 --> 10 5 ╠ ╨┬7 ─╙╥ 14 <-- 12 6 ═ ╨┴2 ─OUT 15 --> 11 2 ╘HIS ASSUMES THAT YOU WANT TO CONNECT ALL OF THE COMMUNICATION LINES. ╔ DID IT THIS WAY BECAUSE THE ├128 PROGRAMMERS REFERENCE GUIDE HAD ALL OF THE SIGNALS ABOVE LISTED. ╔F YOU WANT TO DROP ╥╔ (RING INDICATOR) YOU COULD ALSO USE AN ╠╘1134 WHICH HAS 4 DRIVERS AND 4 RECEIVERS. ╨ARTS ╙UBSTITUTION: ╘HERE ARE OTHER ╔├'S AVAILABLE WHICH WILL WORK IN THIS APPLICATION. ╘HE RS232 BUS LEVELS FOR THE ╠╘ PARTS ARE SPEC'ED AT ▐ +/- 7V TYPICAL, WHILE THE ═┴╪╔═ PARTS ARE +/-9V TYPICAL. (┬OTH ARE MIN AT +/- 5V WHICH SHOULD WORK IN ALL APPLICATIONS). ╔ THINK THAT AN INTERFACE CAN BE DONE WITH ONLY 3 LINES, ─IN(╥X), ─OUT(╘X), AND EITHER ─╙╥ OR ├╘╙, SO IF YOU CAN'T GET THE ╠╘1133 ONE OF THESE OTHERS MIGHT WORK, ALTHOUGH THE PINOUTS WOULD BE DIFFERENT. ╘HE MAX YOU WOULD NEED IS WHAT THE ╠╘1133 SUPPLIES, 3 DRIVERS & 5 RECEIVERS. ╚ERE IS A DESCRIPTION OF PARTS THAT MIGHT BE SUBSTITUTED: (╬OTE, WITH ALL OF THEM YOU SHOULD USE A BYPASS CAP ON THE +5V SUPPLY WHICH ╔ HAVE ╬╧╘ INCLUDED IN THE COUNTS BELOW.) ╥╙232 ╥╙232 # OF ┼╪╘┼╥╬┴╠ ╬┴═┼ ╨╔╬╙ ─╥╔╓┼╥╙ ╥┼├┼╔╓┼╥╙ ├┴╨╙ ├╧══┼╬╘╙ ------------------------------------------------------------------------- ╠INEAR ╘ECHNOLOGY PARTS... (╧N THE PARTS WITH SHUTDOWN (╙─), THE PIN MUST BE TIED TO +5 TO OPERATE) ╠╘1133 24 3 5 4 ╔N ARTICLE ABOVE ------------------------------------------------------------------------- ╠╘1130 28 5 5 4 ╧VERKILL (╙─P14) ╠╘1131 28 5 4 4 2 EX ─R, 1 < ╥CVR ╠╘1132 24 5 3 4 2 EX ─R, 2 < ╥CVR ╠╘1134 24 4 4 4 1 < ╥CVR ╠╘1136 28 4 5 4 1 EX ─R (╙─P14) ╠╘1137 28 3 5 4 ╙─P13 ╠╘1138 28 5 3 4 ╠╘1132 W/╙─P13 ═┴╪╔═ PARTS... (╙OME ALSO HAVE A ╘╘╠ ┼╬_ PIN THAT MUST BE TIED TO 0V TO OPERATE) (╧N THESE PARTS, ╙─ MUST BE TIED TO 0V TO OPERATE!) ═┴╪232 16 2 2 4 ═AY WORK ═┴╪233 20 2 2 0! ╬O EXTERNAL CAPS ═┴╪235 24 5 5 0! ╧VERKILL, BUT ╬╧ CAPS, ╙─P21, ┼╬_P20 ═┴╪236 24 4 3 4 1 EX ─R, 2 < ╥CVR, ╙─P21, ┼╬_P20 ═┴╪237 24 5 3 4 2 EX ─╥, 2 < ╥CVR ═┴╪238 24 4 4 4 1 EX ─╥, 1 < ╥CVR ╔N SUMMARY, YOU CAN SEE THERE ARE MANY DIFFERENT PARTS YOU COULD USE, ESPECIALLY IF YOU DON'T NEED ALL THE SIGNALS. ╘HE ═┴╪╔═ PARTS SEEM TO DO THE JOB IN FEWER PINS AND A LITTLE BETTER TYPICAL DRIVE SPEC AND ╔ WOULD RECOMMEND THE ═┴╪235 OVERALL SINCE YOU ONLY NEED 1 BYPASS CAP TO MAKE IT OPERATE! ============================================================================= ╔NTRODUCTION TO THE ╓╔├-╔╔ BY ╨ASI '┴LBERT' ╧JALA ( ... ) ╘HE ╓IDEO ╔NTERFACE ├ONTROLLER USED IN ├64 HAVE SEVERAL DIFFERENT OPERATING MODES AND DIFFERENT GRAPHICAL PRIMITIVES. ┬ASICALLY THERE IS A) CHARACTER MODE, B) BITMAP MODE AND C) MOVABLE OBJECTS THAT CAN BE MIXED WITH THE OTHER GRAPHICS. ╘HESE PRIMITIVES CAN ALSO BE PUT INTO A MORE COLORFUL MODE, BUT YOU LOSE HALF OF THE RESOLUTION IN THAT PROCESS. ╔. ╙TANDARD ├HARACTER ─ISPLAY ═ODE ╔N THE CHARACTER DISPLAY MODE, ╓╔├ FETCHES CHARACTER POINTERS FROM VIDEO MATRIX, WHICH CONSISTS OF 1000 8-BIT BYTES FORMATTED AS 25 ROWS OF 40 CHARACTERS EACH. ╘HE 8-BIT CHARACTER CODE IMPLIES 256 DIFFERENT CHARACTERS SIMULTANEOUSLY ONSCREEN. ┼ACH CHARACTER CODE CAN HAVE AN UNIQUE IMAGE, WHICH CONSISTS OF 8 BYTES IN CHARACTER MEMORY. ╘HE POSITION OF THE CHARACTER MEMORY CAN BE MOVED WITH THE CHARACTER BASE POINTER AND THUS IT IS POSSIBLE TO HAVE SEVERAL CHARACTER SETS SIMULTANEOSLY IN MEMORY. ╧NE CHARACTER MEMORY IS 2048 BYTES. ╔N ADDITION TO THE CHARACTER CODE, EACH POSITION IN VIDEO MATRIX HAS AN ASSOCIATED COLOR NYBBLE (4 BITS) IN COLOR MEMORY ($─800-$─╞╞╞). ╞OR EACH ZERO-BIT IN THE CHARSET THE BACKGROUND COLOR FROM REGISTER $21 IS DISPLAYED, THE COLOR-NYBBLE IS USED FOR THE ONE-BIT. ╔╔. ├HARACTER ═ULTICOLOR ═ODE ╔N CHARACTER MULTICOLOR MODE, COLOR SELECTION IS INCREASED. ┼ACH BYTE IS FETCHED FROM THE CHARACTER MEMORY JUST LIKE IN THE STANDARD CHARACTER MODE, BUT THEY ARE INTERPRETED DIFFERENTLY. ╔N THIS MODE BYTES ARE DIVIDED INTO BIT-PAIRS. ╞OR BIT PAIR "00" THE BACKGROUND COLOR FROM REGISTER $21 IS DISPLAYED, BACKGROUND COLOR #1 IS USED FOR BIT PAIR "01" AND BACKGROUND COLOR #2 FOR BIT PAIR "10". ╘HE COLOR NYBBLE WILL DEFINE THE COLOR FOR BIT PAIR "11". ╘HE HIGHEST BIT IN THE COLOR MEMORY DEFINES WHETHER THE CHARACTER IS TO BE DISPLAYED IN MULTICOLOR ("1") OR IN STANDARD MODE ("0"). ┬ECAUSE OF THIS, ONLY COLORS IN THE RANGE FROM 0 TO 7 ARE POSSIBLE FOR BIT PAIR "11". ┴ND SINCE TWO BITS ARE REQUIRED TO SPECIFY ONE DOT COLOR, THE CHARACTER IS NOW DISPLAYED AS A 4X8 MATRIX INSTEAD OF THE 8X8 MATRIX AND THE SIZE OF THE DOTS ARE DOUBLED HORIZONTALLY. ╔╔╔. ┼XTENDED ├OLOR ═ODE ╘HE EXTENDED COLOR MODE ALLOWS THE SELECTION OF ONE BACKGROUND COLOR FROM FOUR POSSIBILITIES FOR EACH CHARACTER POSITION IN THE NORMAL 8X8 RESOLUTION. ╘HE CHARACTER IMAGE DATA IS PROCESSED LIKE IN STANDARD CHARACTER MODE, BUT THE TWO MOST SIGNIFICANT BITS IN THE CHARACTER CODE (VIDEO MATRIX) ARE USED TO SELECT THE RIGHT BACKGROUND COLOR REGISTER. ╧NLY CHARACTER IMAGES FROM 0 TO 63 ARE ACCESSIBLE, BECAUSE TWO OF THE MOST SIGNIFICANT BITS ARE USED FOR THE BACKGROUND COLOR SELECTION. ┼XTENDED COLOR MODE AND MULTICOLOR MODE SHOULD NOT BE SELECTED SIMULTANEOSLY, BECAUSE THIS WILL RESULT A BLACK SCREEN. ╚OWEVER, THIS IS A VERY EASY WAY TO HIDE SOMETHING IF NEEDED. ╔╓. ╙TANDARD ┬IT ═AP ═ODE ╔N BIT MAP MODE, A ONE-TO-ONE CORRESPONDENCE EXISTS BETWEEN EACH DISPLAYED DOT AND A MEMORY BIT. ╘HE BIT MAP PROVIDES A RESOLUTION OF 320╚ X 200╓ INDIVIDUALLY CONTROLLED PIXELS. ╘HE VIDEO MATRIX IS STILL ACCESSED AS IN CHARACTER MODE, BUT THE DATA IS INTERPRETED AS COLOR DATA. ╫HEN A BIT IS "0" IN THE BIT MAP DATA, THE COLOR FROM THE LOWER NYBBLE IS SELECTED. ╘HE HIGHER NYBBLE FROM THE VIDEO MATRIX IS USED FOR THE BIT "1". ╓. ═ULTICOLOR ┬IT ═AP ═ODE ╔N MULTICOLOR BIT MAP MODE TWO BITS IN THE BIT MAP MEMORY DETERMINE THE COLOR OF ONE PIXEL. ╔F THE BIT PAIR IS "11", THE COLOR FOUND FROM THE COLOR MEMORY IS USED. ╘HE BACKGROUND COLOR IS USED FOR BIT PAIR "00" AND THE VIDEO MATRIX DEFINES THE COLORS FOR BIT PAIRS "01" AND "10". ┴S IT TAKES TWO BITS TO DEFINE ONE PIXEL COLOR, THE HORIZAONTAL RESOLUTION IS HALVED TO 160╚ X 200╓. ╓╔. ═OVABLE ╧BJECT ┬LOCKS (═╧┬S) ╘HE MOVABLE OBJECT BLOCK IS A SPECIAL TYPE OF GRAPHICAL OBJECT WHICH CAN BE DISPLAYED INDEPENDENTLY FROM THE OTHER GRAPHICS. ┼ACH ONE OF THE ═╧┬S CAN BE MOVED INDEPENDENTLY ANYWHERE IN THE SCREEN. ┼IGHT UNIQUE ═╧┬S CAN BE DISPLAYED SIMULATANIOUSLY, EACH DEFINED BY 64 BYTES IN MEMORY WHICH ARE DISPLAYED AS A 24 X 21 PIXEL ARRAY. ┼ACH ═╧┬ CAN BE SELECTIVELY ENABLED (═N┼="1") OR DISABLED (═N┼="0"). ┴ ═╧┬ IS POSITIONED VIA ITS ╪ AND ┘ POSITION REGISTERS. ╬INE BITS ARE NEEDED TO DEFINE THE VERTICAL POSITION AND THE MOST SIGNIFICANT BITS OF ALL ═╧┬S ARE STORED IN THE REGISTER $10. ┴S ╪ LOCATIONS 23 TO 347 AND ┘ LOCATIONS 50 TO 249 ARE ENTIRELY VISIBLE ON THE SCREEN, ═╧┬S CAN BE SMOOTHLY MOVED TO AN OFF-SCREEN POSITION. ┼ACH ═╧┬ HAS ITS OWN COLOR REGISTER AND A ═╧┬ CAN BE DISPLAYED EITHER IN STANDARD OR MULTICOLOR MODE (═N═├="1"). ┴S USUALLY, MULTICOLOR MODE GIVES MORE COLORS, BUT HALVES THE HORIZONTAL RESOLUTION. ╔N MULTICOLOR MODE BIT PAIR "00" IS TRANSPARENT, THE ═╧┬ COLOR REGISTER DEFINES THE COLOR FOR PAIR "10", AND ═╧┬ MULTICOLOR REGISTERS GIVE THE COLORS FOR PAIRS "01" AND "11". ═╧┬S CAN BE SELECTIVELY EXPANDED IN BOTH DIRECTIONS. ╫HEN ═╧┬ IS EXPANDED, THE PIXEL SIZE ALSO EXPANDS AND IT IS STILL DISPLAYED AS 24 X 21 MATRIX (12 X 21 IN MULTICOLOR MODE). ═╧┬ PRIORITIES DEFINE WHETHER A ═╧┬ APPEARS BEHIND OR ON TOP OF THE CHARACTER OR BIT MAP GRAPHICS. ┴ "1" IN ═N─╨ MEANS ═╧┬ IS DISPLAYED BEHIND. ═╧┬ COLLISION REGISTERS MAY BE USED TO DETECT IF A NON-TRANSPARENT DATA OF TWO ═╧┬S OR A ═╧┬ AND CHARACTER OR BITMAP FOREGROUND DATA IS COLLIDING. [┼D'S ╬OTE: ═╧┬'S ARE ╙PRITES. ├OMMODORE INITIALLY REFERRED TO THEM AS ═╧┬'S AND STILL DOES IN SOME AREAS.] ╓╔╔. ╧THER FEATURES ╘HE DISPLAY SCREEN MAY BE BLANKED BY SETTING THE ─┼╬ BIT TO A "0". ╘HE ENTIRE SCREEN WILL BE FILLED WITH THE BORDER COLOR AS SET IN REGISTER 32 ($20). ╫HEN THE SCREEN IS BLANKED, ╓╔├ WILL NEED ONLY TRANSPARENT MEMORY CYCLES AND THE PROCESSOR IS NOT SLOWED DOWN. ╚OWEVER, ═╧┬ DATA IS STILL FETCHED, IF THE ═╧┬S ARE NOT ALSO DISABLED. ╘HE NORMAL DISPLAY CONSISTS OF 25 ROWS OF 40 CHARACTERS EACH. ╘HE DISPLAY WINDOW CAN BE REDUCED TO 24 ROWS AND 38 CHARACTERS. ╘HIS HAS NO EFFECT ON HOW THE DATA IS INTERPRETED, ONLY THE CHARACTERS NEXT TO THE BORDER ARE COVERED BY THE BORDER. ╥╙┼╠ CONTROLS THE NUMBER OF ROWS ("1" FOR 25 ROWS) AND ├╙┼╠ CONTROLS THE NUMBER OF COLUMNS ("1" FOR 40 COLUMNS). ╘HE DISPLAY DATA MAY BE SCROLLED UP TO ONE CHARACTER SPACE IN BOTH VERTICAL AND HORIZONTAL DIRECTION. ╨OSITION OF THE SCREEN IS SET WITH THE 3 LOWEST ORDER (LEAST SIGNIFICANT) BITS IN REGISTERS 22 ($16) AND 17 ($11). ╠IGHT PEN LATCH IS USED TO CATCH THE POSITION OF THE LIGHT PEN WHEN A PULSE IS RECEIVED IN THE ╠╨ PIN. ╘HE VALUE IS LATCHED ONLY ONCE IN A FRAME. ╘HE RASTER REGISTER IS A DUAL-FUNCTION REGISTER. ┴ READ FROM THE RASTER REGISTER RETURNS THE CURRENT RASTER POSITION AND A WRITE TO IT WILL SET THE RASTER COMPARE VALUE. ╫HEN THE WRITTEN VALUE AND THE CURRENT RASTER LINE MATCHES, A RASTER INTERRUPT IS GENERATED IF ENABLED. ╥ASTER REGISTER HAS ITS MOST SIGNIFICANT (9TH) BIT IN REGISTER 17 ($11). ╘HE INTERRUPT REGISTER SHOWS THE STATUS OF THE FOUR SOURCES OF INTERRUPT. ┴ CORRESPONDING BIT WILL BE SET TO "1" WHEN AN INTERRUPT SOURCE HAS GENERATED AN INTERRUPT REQUEST. ╘O ENABLE AN INTERRUPT REQUEST TO SET THE /╔╥╤ OUTPUT TO ZERO, THE CORRESPONDING ENABLE BIT IN REGISTER 26 ($1A) MUST BE SET TO "1". ╘HE INTERRUPT LATCH MAY ONLY BE CLEARED BY WRITING A "1" TO THE DESIRED LATCH IN THE INTERRUPT REGISTER. ----------------------------------------------------------------------------- ╓╔├ REGISTER MAP (┬ASE ADDRESS $D000) ┴DDRESS ─┬7 ─┬6 ─┬5 ─┬4 ─┬3 ─┬2 ─┬1 ─┬0 ─ESCRIPTION ------------------------------------------------------------------- 00 $00 ═0╪7 ═0╪6 ═0╪5 ═0╪4 ═0╪3 ═0╪2 ═0╪1 ═0╪0 ═╧┬ 0 ╪-POSITION 01 $01 ═0┘7 ═0┘6 ═0┘5 ═0┘4 ═0┘3 ═0┘2 ═0┘1 ═0┘0 ═╧┬ 0 ┘-POSITION 02 $02 ═1╪7 ═1╪6 ═1╪5 ═1╪4 ═1╪3 ═1╪2 ═1╪1 ═1╪0 ═╧┬ 1 ╪-POSITION 03 $03 ═1┘7 ═1┘6 ═1┘5 ═1┘4 ═1┘3 ═1┘2 ═1┘1 ═1┘0 ═╧┬ 1 ┘-POSITION 04 $04 ═2╪7 ═2╪6 ═2╪5 ═2╪4 ═2╪3 ═2╪2 ═2╪1 ═2╪0 ═╧┬ 2 ╪-POSITION 05 $05 ═2┘7 ═2┘6 ═2┘5 ═2┘4 ═2┘3 ═2┘2 ═2┘1 ═2┘0 ═╧┬ 2 ┘-POSITION 06 $06 ═3╪7 ═3╪6 ═3╪5 ═3╪4 ═3╪3 ═3╪2 ═3╪1 ═3╪0 ═╧┬ 3 ╪-POSITION 07 $07 ═3┘7 ═3┘6 ═3┘5 ═3┘4 ═3┘3 ═3┘2 ═3┘1 ═3┘0 ═╧┬ 3 ┘-POSITION 08 $08 ═4╪7 ═4╪6 ═4╪5 ═4╪4 ═4╪3 ═4╪2 ═4╪1 ═4╪0 ═╧┬ 4 ╪-POSITION 09 $09 ═4┘7 ═4┘6 ═4┘5 ═4┘4 ═4┘3 ═4┘2 ═4┘1 ═4┘0 ═╧┬ 4 ┘-POSITION 10 $0A ═5╪7 ═5╪6 ═5╪5 ═5╪4 ═5╪3 ═5╪2 ═5╪1 ═5╪0 ═╧┬ 5 ╪-POSITION 11 $0B ═5┘7 ═5┘6 ═5┘5 ═5┘4 ═5┘3 ═5┘2 ═5┘1 ═5┘0 ═╧┬ 5 ┘-POSITION 12 $0C ═6╪7 ═6╪6 ═6╪5 ═6╪4 ═6╪3 ═6╪2 ═6╪1 ═6╪0 ═╧┬ 6 ╪-POSITION 13 $0D ═6┘7 ═6┘6 ═6┘5 ═6┘4 ═6┘3 ═6┘2 ═6┘1 ═6┘0 ═╧┬ 6 ┘-POSITION 14 $0E ═7╪7 ═7╪6 ═7╪5 ═7╪4 ═7╪3 ═7╪2 ═7╪1 ═7╪0 ═╧┬ 7 ╪-POSITION 15 $0F ═7┘7 ═7┘6 ═7┘5 ═7┘4 ═7┘3 ═7┘2 ═7┘1 ═7┘0 ═╧┬ 7 ┘-POSITION 16 $10 ═7╪8 ═6╪8 ═5╪8 ═4╪8 ═3╪8 ═2╪8 ═1╪8 ═0╪8 ═╙┬ OF ╪-POSITION 17 $11 ╥├8 ┼├═ ┬══ ─┼╬ ╥╙┼╠ ┘2 ┘1 ┘0 (╙EE TEXT) 18 $12 ╥├7 ╥├6 ╥├5 ╥├4 ╥├3 ╥├2 ╥├1 ╥├0 ╥ASTER REGISTER 19 $13 ╠╨╪8 ╠╨╪7 ╠╨╪6 ╠╨╪5 ╠╨╪4 ╠╨╪3 ╠╨╪2 ╠╨╪1 ╠IGHT ╨EN ╪ 20 $14 ╠╨┘7 ╠╨┘6 ╠╨┘5 ╠╨┘4 ╠╨┘3 ╠╨┘2 ╠╨┘1 ╠╨┘0 ╠IGHT ╨EN ┘ 21 $15 ═7┼ ═6┼ ═5┼ ═4┼ ═3┼ ═2┼ ═1┼ ═0┼ ═╧┬ ┼NABLE 22 $16 - - ╥┼╙ ═├═ ├╙┼╠ ╪2 ╪1 ╪0 (╙EE TEXT) 23 $17 ═7┘┼ ═6┘┼ ═5┘┼ ═4┘┼ ═3┘┼ ═2┘┼ ═1┘┼ ═0┘┼ ═╧┬ ┘-EXPAND 24 $18 ╓═13 ╓═12 ╓═11 ╓═10 ├┬13 ├┬12 ├┬11 - ═EMORY ╨OINTERS 25 $19 ╔╥╤ - - - ╔╠╨ ╔══├ ╔═┬├ ╔╥╙╘ ╔NTERRUPT ╥EGISTER 26 $1A - - - - ┼╠╨ ┼══├ ┼═┬├ ┼╥╙╘ ┼NABLE ╔NTERRUPT 27 $1B ═7─╨ ═6─╨ ═5─╨ ═4─╨ ═3─╨ ═2─╨ ═1─╨ ═0─╨ ═╧┬-─┴╘┴ ╨RIORITY 28 $1C ═7═├ ═6═├ ═5═├ ═4═├ ═3═├ ═2═├ ═1═├ ═0═├ ═╧┬ ═ULTICOLOR SELECT 29 $1D ═7╪┼ ═6╪┼ ═5╪┼ ═4╪┼ ═3╪┼ ═2╪┼ ═1╪┼ ═0╪┼ ═╧┬ ╪-┼XPAND 30 $1E ═7═ ═6═ ═5═ ═4═ ═3═ ═2═ ═1═ ═0═ ═╧┬-═╧┬ ├OLLISION 31 $1F ═7─ ═6─ ═5─ ═4─ ═3─ ═2─ ═1─ ═0─ ═╧┬-─┴╘┴ ├OLLISION 32 $20 - - - - ┼├3 ┼├2 ┼├1 ┼├0 ┼XTERIOR ├OLOR 33 $21 - - - - ┬0├3 ┬0├2 ┬0├1 ┬0├0 ┬ACKGROUND #0 ├OLOR 34 $22 - - - - ┬1├3 ┬1├2 ┬1├1 ┬1├0 ┬ACKGROUND #1 ├OLOR 35 $23 - - - - ┬2├3 ┬2├2 ┬2├1 ┬2├0 ┬ACKGROUND #2 ├OLOR 36 $24 - - - - ┬3├3 ┬3├2 ┬3├1 ┬3├0 ┬ACKGROUND #3 ├OLOR 37 $25 - - - - ══03 ══02 ══01 ══00 ═╧┬ ═ULTICOLOR #0 38 $26 - - - - ══13 ══12 ══11 ══10 ═╧┬ ═ULTICOLOR #1 39 $27 - - - - ═0├3 ═0├2 ═0├1 ═0├0 ═╧┬ 0 ├OLOR 40 $28 - - - - ═1├3 ═1├2 ═1├1 ═1├0 ═╧┬ 1 ├OLOR 41 $29 - - - - ═2├3 ═2├2 ═2├1 ═2├0 ═╧┬ 2 ├OLOR 42 $2A - - - - ═3├3 ═3├2 ═3├1 ═3├0 ═╧┬ 3 ├OLOR 43 $2B - - - - ═4├3 ═4├2 ═4├1 ═4├0 ═╧┬ 4 ├OLOR 44 $2C - - - - ═5├3 ═5├2 ═5├1 ═5├0 ═╧┬ 5 ├OLOR 45 $2D - - - - ═6├3 ═6├2 ═6├1 ═6├0 ═╧┬ 6 ├OLOR 46 $2E - - - - ═7├3 ═7├2 ═7├1 ═7├0 ═╧┬ 7 ├OLOR ═N╪ = ═╧┬ N ╪ POSITION ═N┘ = ═╧┬ N ┘ POSITION ╥├ = ╥ASTER COMPARE REGISTER ┼├═ = ┼XTENDED COLOR MODE ═┬┬ = ┬IT MAP MODE ─┼╬ = ─ISPLAY ENABLE ╥╙┼╠ = ╥OW SELECT ┘ = ╙CREEN ┘ POSITION ╠╨╪ = ╠IGHT PEN ╪ POSITION ╠╨┘ = ╠IGHT PEN ┘ POSITION ═N┼ = ═╧┬ N ┼NABLE ╥┼╙ = ┴LWAYS SET TO ZERO! ═├═ = ═ULTICOLOR MODE ├╙┼╠ = ├OLUMN SELECT ╪ = ╙CREEN ╪ POSITION ═N┘┼ = ═╧┬ N ┘ EXPAND ╓═ = ╓IDEO MATRIX POINTER ├┬ = ├HARACTER BASE POINTER ═N─╨ = ═╧┬ TO DATA PRIORITY ═N═├ = ═╧┬ N MULTICOLOR SELECT ═N╪┼ = ═╧┬ N ╪ EXPAND ============================================================================= ╠╔╘╘╠┼ ╥┼─ ╥┼┴─┼╥: ═╙-─╧╙ FILE READER FOR THE 128 AND 1571/81 DRIVES. BY ├RAIG ┬RUCE <CSBRUCE@NEUMANN.UWATERLOO.CA> 1. ╔╬╘╥╧─╒├╘╔╧╬ ╘HIS ARTICLE PRESENTS A PROGRAM THAT READS ═╙-─╧╙ FILES AND THE ROOT DIRECTORY OF ═╙-─╧╙ DISKS. ╘HE PROGRAM COPIES ONLY FROM DRIVE TO DRIVE WITHOUT BUFFERING FILE DATA INTERNALLY. ╘HIS IS SIMPLER AND IMPOSES NO LIMITS ON THE SIZE OF THE FILES TRANSFERRED, ALTHOUGH IT REQUIRES THE USE OF TWO DISK DRIVES (OR A LOGICAL DRIVE). ╘HE USER-INTERFACE CODE IS WRITTEN IN ┬┴╙╔├ AND PRESENTS A FULL-SCREEN FILE SELECTION MENU. ╘HE GRUNT-WORK CODE IS WRITTEN IN ASSEMBLY LANGUAGE AND OPERATES AT MAXIMUM VELOSITY. ╘HE ┬URST ├OMMAND ╔NSTRUCTION ╙ET OF THE 1571/81 IS USED TO READ THE ═╙-─╧╙ DISK BLOCKS AND THE STANDARD KERNEL ROUTINES ARE USED FOR OUTPUTTING THE DATA. (╔ AM AN OPERATING SYSTEMS SPECIALIST, SO ╔ CALL IT A KERN┼L!) ╘HUS, THE ═╙-─╧╙ FILES MUST BE READ FROM A 1571 OR 1581 DISK DRIVE, BUT THE OUTPUT DEVICE MAY BE ANY DISK DRIVE TYPE, THE SCREEN OR A PRINTER, OR A VIRTUAL DRIVE TYPE SUCH AS ╥┴═╠INK, ╥┴═─RIVE, OR ╥┴═─╧╙ (FOR THE ╥┼╒). ╔T IS INTERESTING TO NOTE THAT THE DATA CAN BE READ IN FROM AN ═╙-─╧╙ DISK FASTER THAN IT CAN BE WRITTEN OUT TO A 1571, 1581, OR EVEN A ╥┴═─╧╙ FILE. ┴ ╥┴═╠INK CAN SWALLOW THE DATA ONLY SLIGHTLY FASTER THAN IT CAN BE READ. ╠ITTLE ╥ED ╥EADER (╠╥╥) SUPPORTS DOUBLE DENSITY 3.5" DISKS FORMATTED WITH 80 TRACKS, 9 SECTORS PER TRACK, AND 2 SIDES WITH A 1581 AND 5.25" DOUBLE DENSITY DISKS FORMATTED WITH 40 TRACKS, 9 SECTORS PER TRACK, AND 2 SIDES WITH A 1571. ┴ LIMIT OF 128 DIRECTORY ENTRIES AND 3 ╞ILE ┴LLOCATION ╘ABLE (╞┴╘) SECTORS IS IMPOSED. ╘HERE MUST BE 2 COPIES OF THE ╞┴╘ AND THE CLUSTER SIZE MAY BE 1 OR 2 SECTORS. ╘HE SECTOR SIZE MUST BE 512 BYTES. ╧H, ABOUT THE NAME. ╔T IS A PLAY ON THE NAME OF ANOTHER ═╙-─╧╙ FILE COPIER AVAILABLE FOR THE ├-128. "╠ITTLE" MEANS THAT IT IS SMALLER IN SCOPE THAN THE OTHER PROGRAM, AND "╥ED" IS A DIFFERENT PRIMARY COLOR TO AVOID ANY LEGAL COMPLICATIONS. ╔T IS ALSO THE NON-WHITE COLOR OF THE FLAG OF THE COUNTRY OF ORIGIN OF THIS PROGRAM (NO, ╔ AM NOT ╩APANESE). ┴LSO, THIS PROGRAM IS ╨UBLIC ─OMAIN ╙OFTWARE, AS IS ALL SOFTWARE ╔ DEVELOP FOR 8-BIT ├OMMODORE ├OMPUTERS. ╞EEL FREE TO ┼-MAIL ME IF YOU HAVE QUESTIONS OR COMMENTS ABOUT THIS ARTICLE. 2. ╒╙┼╥ ╟╒╔─┼ ╠╧┴─ AND ╥╒╬ THE "LRR.128" ┬┴╙╔├ PROGRAM FILE. ╫HEN THE PROGRAM IS FIRST RUN, IT WILL DISPLAY AN "INITIALIZING" MESSAGE AND WILL LOAD IN THE BINARY MACHINE LANGUAGE PACKAGE FROM THE "CURRENT" ├OMMODORE ─╧╙ DRIVE (THE CURRENT DRIVE IS OBTAINED FROM ╨┼┼╦(186) - THE LAST DEVICE ACCESSED). ╘HE BINARY PACKAGE IS LOADED ONLY ON THE FIRST RUN AND IS NOT RELOADED ON SUBSEQUENT RUNS IF THE PACKAGE ╔─ FIELD IS IN PLACE. 2.1. ═┴╔╬ ╙├╥┼┼╬ ╘HE MAIN SCREEN OF THE PROGRAM IS THEN DISPLAYED. ╘HE MAIN SCREEN OF THE PROGRAM WILL LOOK SOMETHING LIKE THIS: ═╙-─┼╓=9 ═╙-╘┘╨┼=1581 ├┬═-─┼╓=8 ╬╒═ ╙ ╘╥╬ ╘┘╨ ╞╔╠┼╬┴═┼ ┼╪╘ ╠┼╬╟╘╚ --- - --- --- -------- --- ------ 1 * ┴╙├ ╙┼╤ ╚┴├╦4 ╘╪╘ 120732 2 ┬╔╬ ╨╥╟ ╥┴═─╧╙ ╙╞╪ 34923 ─=─╔╥┼├╘╧╥┘ ═=═╙-─┼╓ ╞=├┬═-─┼╓ ╤=╤╒╔╘ ╘=╘╧╟╟╠┼-├╧╠╒═╬, ├=├╧╨┘-╞╔╠┼╙, +/- ╨┴╟┼ EXCEPT THAT IMMEDIATELY AFTER STARTING UP, "<NO FILES>" WILL BE DISPLAYED RATHER THAN FILENAMES. ╘HE "═╙-─┼╓" AND "═╙-╘┘╨┼" FIELDS GIVE THE DEVICE NUMBER AND TYPE OF THE DRIVE CONTAINING THE ═╙-─╧╙ DISK TO COPY FROM, AND THE "├┬═-─┼╓" GIVES THE DEVICE NUMBER OF THE DRIVE/VIRTUAL DRIVE/CHARACTER DEVICE TO COPY FILE DATA TO. ╔NFORMATION ABOUT ALL ═╙-─╧╙ FILES IN THE ROOT DIRECTORY OF THE ═╙-─╧╙ DISK IS DISPLAYED IN COLUMNS BELOW THE DRIVE INFORMATION. "╬╒═" GIVES THE NUMBER OF THE ═╙-─╧╙ FILE IN THE DIRECTORY LISTING, AND "╙" INDICATES WHETHER THE FILE IS "SELECTED" OR NOT. ╔F THE FILE IS SELECTED, AN ASTERISK (*) IS DISPLAYED; OTHERWISE, A BLANK IS DISPLAYED. ╫HEN YOU LATER ENTER ├OPY ═ODE, ONLY THE FILES THAT HAVE BEEN "SELECTED" ARE COPIED. ╘HE "╘╥╬" FIELD INDICATES THE CHARACTER TRANSLATION SCHEME TO BE USED WHEN THE FILE IS COPIED. ┴ VALUE OF "┬╔╬" (BINARY) MEANS NO TRANSLATION AND A VALUE OF "┴╙├" (ASCII) MEANS THE FILE CHARACTERS ARE TO BE TRANSLATED FROM ═╙-─╧╙ ┴╙├╔╔ (OR "┴╙├╔╔-├R╠F") TO ╨┼╘╙├╔╔. ╘HE "╘┘╨" FIELD INDICATES THE TYPE OF ├OMMODORE-─╧╙ FILE TO CREATE FOR WRITING THE ═╙-─╧╙ FILE CONTENTS INTO. ╘HE POSSIBLE VALUES ARE "╙┼╤" (SEQUENTIAL) AND "╨╥╟" (PROGRAM). ╘HE VALUES OF THE ╘╥╬ AND ╘┘╨ FILEDS ARE SET INDEPENDENTLY, SO YOU CAN COPY BINARY DATA TO ╙┼╤ FILES AND ASCII DATA TO ╨╥╟ FILES IF YOU WISH. ╘HE "╞╔╠┼╬┴═┼" AND "┼╪╘" FIELDS GIVE THE FILENAME AND EXTENSION TYPE OF THE ═╙-─╧╙ FILES AND "╠┼╬╟╘╚" GIVES THE EXACT LENGTH OF THE FILES IN BYTES. ╬OTE THAT IF YOU PERFORM "┴╙├" TRANSLATION ON A FILE, ITS ╨┼╘╙├╔╔ VERSION WILL HAVE A SHORTER LENGTH. 2.2. ╒╙┼╥ ├╧══┴╬─╙ ╘HE BOTTOM OF THE SCREEN GIVES THE COMMAND SUMMARY. ┴FTER STARTING THE PROGRAM, YOU WILL WANT TO SETUP THE ═╙-─╧╙ AND ├┬═-─╧╙ DRIVES WITH THE "═" AND "╞" COMMANDS. ╙IMPLY PRESS THE (LETTER) KEY CORRESPONDING TO THE COMMAND NAME TO ACTIVATE THE COMMAND. ╨RESSING ═ WILL PROMPT YOU FOR THE ═╙-─╧╙ ─RIVE ╬UMBER AND THE ═╙-─╧╙ ─RIVE ╘YPE. ╔N BOTH CASES, TYPE THE NUMBER AND PRESS ╥┼╘╒╥╬. (╙ORRY FOR INSULTING ALL NON-NOVICES OUT THERE, BUT ╔ WANT TO BE COMPLETE). ╘HE ═╙-─╧╙ DRIVE NUMBER CANNOT BE THE SAME AS THE ├┬═-─╧╙ DRIVE NUMBER (SINCE THE PROGRAM COPIES FROM DRIVE-TO-DRIVE WITHOUT INTERNAL BUFFERING). ╞OR THE DRIVE TYPE, ENTER AN "8", "81", OR "1581" FOR A 1581 DRIVE OR ANYTHING ELSE FOR A 1571 DRIVE. ╨RESSING ╞ WILL PROMPT YOU FOR THE ├┬═-─╧╙ DEVICE NUMBER. ┘OU MAY ENTER A NUMBER FROM 0 TO 30, EXCEPT THAT IT MUST NOT BE THE ═╙-─╧╙ DRIVE NUMBER. ┼NTER A "1" FOR ├ASSETTE ─RIVE (╟OD FORBID!), A "3" FOR THE SCREEN, A "4" FOR THE PRINTER (WITH AN AUTOMATIC SECONDARY ADDRESS OF 7 (LOWERCASE)), ANY NUMBER ABOVE 7 FOR A ├OMMODORE DISK DRIVE OR SPECIAL VIRTUAL DRIVE, OR A VALUE OF "0" FOR THE SPECIAL "NULL" DRIVE. ┴ ├┬═-─┼╓ VALUE OF 0 WILL CASE THE PROGRAM TO READ ═╙-─╧╙ FILES AND DO NOTHING WITH THE OUTPUT. ┘OU CAN USE THIS FEATURE TO CHECK OUT THE RAW READING SPEED OF THE PROGRAM. ┴FTER SETTING UP THE DRIVES, PRESS ─ TO READ IN THE ROOT DIRECTORY OFF THE ═╙-─╧╙ DISK. ╘HE DATA WILL COME BLAZING IN FROM THE DISK BUT ┬┴╙╔├ WILL TAKE ITS GOOD OLE TIME SIFTING THROUGH IT. ╞ILENAMES ARE DISPLAYED ON THE SCREEN AS THEY ARE SCANNED IN. ╘HE PROGRAM WILL (EVENTUALLY) RETURN TO THE MAIN SCREEN AND DISPLAY THE FORMATTED FILE INFORMATION. ╧NE NOTE: THE PROCESS OF LOGGING IN A 1581 ═╙-─╧╙ DISK TAKES ABOUT 12 SECONDS (ON MY 1581, ANYWAY), SO BE PATIENT. ┴N ═╙-─╧╙ DISK WILL HAVE TO BE "LOGGED IN" EVERY TIME YOU CHANGE ═╙-─╧╙ DISKS. (─ISKS ARE LOGGED IN AUTOMATICALLY). ┴ COUPLE OF NOTES ABOUT ACCESSING ═╙-─╧╙ DISKS: DON'T TRY TO ACCESS A DEVICE THAT IS NOT PRESENT BECAUSE THE MACHINE LANGUAGE ROUTINES CANNOT HANDLE THIS ERROR FOR SOME REASON AND WILL LOCK UP, REQUIRING A ╙╘╧╨+╥┼╙╘╧╥┼. ┴LSO, MAKE SURE THAT AN ACTUAL ═╙-─╧╙ DISK IS LOADED INTO THE DRIVE. ╔F YOU ACCIDENTALLY PLACE ├OMMODORE-─╧╙ DISK INTO THE ═╙-─╧╙ DRIVE, THE 1581 WILL REPORT AN INVALID BOOT PARAMETERS ERROR (#60), BUT A 1571 WILL LOCK UP (SINCE ╔ DON'T CHECK THE SECTOR SIZE AND MY BURST ROUTINES ARE EXPECTING 512 BYTES TO COME OUT OF A SECTOR WHEREAS ├OMMODORE DISKS HAVE ONLY 256 BYTES PER SECTOR). ╬OW YOU ARE READY TO PICK WHAT FILES YOU WANT COPIED AND HOW YOU WANT THEM COPIED. ┘OU WILL NOTICE THAT A "CURSOR" APPEARS IN THE "╙" COLUMN OF THE FIRST FILE. ┘OU MAY MOVE THE CURSOR AROUND WITH THE CURSOR KEYS: ╒╨, ─╧╫╬, ╠┼╞╘, ╥╔╟╚╘, ╚╧═┼, AND ├╠╥. ├╠╥ (╙╚╔╞╘-╚╧═┼) WILL MOVE THE CURSOR BACK TO THE FIRST FILE ON THE FIRST SCREEN. ┘OU CAN MOVE THE CURSOR AMONG THE SELECT, TRANSLATION, AND FILE-TYPE COLUMNS OF ALL THE FILES. ╨RESSING A ╙╨┴├┼ OR A ╥┼╘╒╥╬ WILL TOGGLE THE VALUE OF THE FIELD THAT THE CURSOR IS ON. ╘O TOGGLE ALL OF THE VALUES OF THE "CURSOR" COLUMN (INCLUDING FILES ON ALL OTHER SCREENS), PRESS ╘. ┘OU WILL NOTICE THAT MOVING THE CURSOR AROUND AND TOGGLING FIELDS IS A BIT SLUGGISH, ESPECIALLY IF YOU ARE IN ╙LOW MODE ON THE 40-COLUMN SCREEN. ─ID ╔ MENTION THAT THIS PROGRAM WILL RUN ON EITHER THE 40 OR 80-COLUMN SCREEN? ╘OGGLING AN ENTIRE COLUMN CAN TAKE A COUPLE OF SECONDS. ╔F THERE ARE MORE THAN 18 ═╙-─╧╙ FILES, YOU CAN PRESS THE "+" AND "-" KEYS TO MOVE AMONG ALL OF THE SCREENS OF FILES. ╘HE CURSOR MOVEMENT KEYS WILL WRAP AROUND ON THE CURRENT SCREEN. "+" IS PAGE FORWARD, AND "-" IS PAGE BACKWARD. ╘HE SCREENS WRAP AROUND TOO. ┴FTER YOU HAVE SELECTED ALL OF THE FILES YOU WANT TO COPY AND THEIR TRANSLATION AND FILE-TYPE FIELDS HAVE BEEN SET, PRESS THE ├ KEY TO GO INTO ├OPY ═ODE (NEXT SECTION). ┴FTER COPYING, YOU ARE RETURNED TO THE MAIN SCREEN WITH ALL OF THE FIELD SETTINGS STILL INTACT. ╘O EXIT FROM THE PROGRAM, PRESS ╤. 2.3. ├╧╨┘ ═╧─┼ ╫HEN YOU ENTER COPY MODE, THE SCREEN WILL CLEAR AND THE NAME OF EACH SELECTED FILE IS DISPLAYED AS IT IS BEING COPIED. ╔F AN ERROR IS ENCOUNTERED ON EITHER THE ═╙-─╧╙ OR ├┬═-─╧╙ DRIVE DURING COPYING, AN ERROR MESSAGE WILL BE DISPLAYED AND COPYING WILL CONTINUE (AFTER YOU PRESS A KEY FOR ═╙-─╧╙ ERRORS). ╘O GENERATE A ├┬═-─╧╙ FILENAME FROM AN ═╙-─╧╙ FILENAME, THE EIGHT FILENAME CHARACTERS ARE TAKEN (INCLUDING SPACES) AND A DOT (.) AND THE THREE CHARACTERS OF THE EXTENSION ARE APPENDED. ╘HEN, ALL SPACES ARE REMOVED, AND IF THE NAME ENDS WITH A DOT (.) CHARACTER, THEN THAT DOT CHARACTER IS REMOVED AS WELL. ╔ THINK THIS IS FAIRLY REASONABLE. ╔F THERE ALREADY IS A FILE WITH THE SAME FILENAME ON THE ├┬═-─╧╙ DISK, THEN YOU WILL BE PROMPTED IF YOU WANT TO OVERWRITE THE FILE OR NOT. ┼NTERING AN "N" WILL ABORT THE COPYING OF THAT FILE AND GO ON TO THE NEXT FILE, AND ENTERING A "Y" (OR ANYTHING ELSE) WILL CAUSE THE ├┬═-─╧╙ FILE TO BE "SCRATCHED" AND THEN RE-WRITTEN. ╘HE PHYSICAL COPYING OF THE FILE IS DONE COMPLETELY IN MACHINE LANGUAGE AND NOTHING IS DISPLAYED ON THE SCREEN WHILE THIS IS HAPPENING, BUT YOU CAN FOLLOW THINGS BY LOOKING AT DAS BLINKIN LICHTES AND LISTENING FOR CLICKS AND GRINDS. ┘OU WILL PROBABLY BE SURPRISED BY THE ═╙-─╧╙ FILE READING SPEED (╔ MEAN IN A GOOD WAY). ╘HE DISK DATA IS READ IN WHOLE TRACKS AND CACHED IN MEMORY AND THE DIRECTORY INFORMATION AND THE ╞┴╘ ARE RETAINED IN MEMORY AS WELL. ╘HE RESULT IS THAT MINIMAL TIME IS SPENT READING DISK DATA, AND NO COSTLY SEEKS ARE REQUIRED FOR OPENING A NEW ═╙-─╧╙ FILE. ┴ RESULT IS THAT SMALL FILES ARE COPIED ONE AFTER ANOTHER VERY QUICKLY. ┘OU WILL HAVE TO WAIT, HOWEVER, ON THE RELATIVELY SLOW STANDARD KERNEL/├OMMODORE-─╧╙ FILE WRITING. ┴ FEW CHANGES HAD TO BE MADE TO THE PROGRAM TO ACCOMODATE THE ╥┴═─╧╙ PROGRAM. ╥┴═─╧╙ USES MEMORY FROM $2300 TO $3╞╞╞ OF ╥┴═0, WHICH IS NOT REALLY A GOOD PLACE FOR A DEVICE DRIVER, AND IT USES SOME OF THE ZERO-PAGE LOCATIONS THAT ╔ WANTED TO USE. ┬UT, DIFFICULTIES WERE OVERCOME. ╘HE IMPORTANCE OF ╥┴═─╧╙ COMPATIBILITY IS THAT IF YOU ONLY HAVE ONE DISK DRIVE BUT YOU HAVE AN ╥┼╒, YOU CAN USE ╥┴═─╧╙ TO STORE THE ═╙-─╧╙ FILES TEMPORARILY. ╔F YOU ONLY HAVE ONE DISK DRIVE AND NO ╥┼╒, YOU ARE ╙╧╠ (╧UT OF ╠UCK) UNLESS YOU CAN GET A ╥AM─ISK-TYPE PROGRAM FOR AN UNEXPANDED 128. ╘HE ╥┴═─╧╙ PROGRAM IS AVAILABLE FROM ╞╘╨ SITE "CCOSUN.CALTECH.EDU" IN FILE "/PUB/RKNOP/UTIL128/RAMDOSII.SFX". ╧NE NOTE ╔ FOUND OUT ABOUT ╥┴═─╧╙: YOU CANNOT USE A ─╧╨┼╬#1,(├╞$),╒(├─),╫ WITH IT LIKE YOU ARE SUPPOSED TO BE ABLE TO; YOU HAVE TO USE A ─╧╨┼╬#1,(├╞$+",╫"),╒(├─) ╚ERE IS A TABLE OF COPYING SPEEDS FOR COPYING FROM 1571S AND 1581S WITH ┴╙├ AND ┬╔╬ TRANSLATION MODES. ┴LL FIGURES ARE IN BYTES/SECOND. ╘HESE RESULTS WERE OBTAINED FROM COPYING A 127,280 BYTE TEXT FILE (THE TEXT OF ├= ╚ACKING ╔SSUE #3). ╞╥╧═ \ ╘╧: "NULL" ╥┴═╠INK ╥┴═─╧╙ ╩─1581 ╩─1571 -------+ ------ ------- ------ ------ ------ 81-BIN ▄ 5772 3441 2146 N/A 644 81-ASC ▄ 5772 3434 2164 N/A 661 71-BIN ▄ 4323 2991 1949 1821 N/A 71-ASC ▄ 4323 2982 1962 1847 N/A ╘HE "NULL" DEVICE IS THAT "0" ├┬═-─╧╙ DEVICE NUMBER, AND A COUPLE OF ENTRIES ARE "N/A" SINCE ╔ ONLY HAVE ONE 1571 AND ONE 1581. ╬OTE THAT MY 71 AND 81 ARE ╩IFFY─╧╙-IFIED, SO THE PERFORMANCE OF A STOCK 71/81 WILL BE POORER. ╩IFFY─╧╙ GIVES ABOUT A 2X PERFORMANCE IMPROVEMENT FOR THE STANDARD FILE ACCESSING CALLS (OPEN, CLOSE, CHRIN, CHROUT). ╥┴═─╧╙ DOESN'T SEEM TO BE AS SNAPPY AS YOU MIGHT THINK. ╘HE "NULL" FIGURES ARE QUITE IMPRESSIVE, BUT THE RAW SECTOR READING SPEED WITHOUT THE OVERHEAD OF MUCKING AROUND WITH FILE ORGANIZATION IS 6700 BYTES/SEC FOR A 1581 AND 4600 ┬/S FOR A 71. ╘HE REASON THAT THE 1571 OPERATES SO QUICKLY IS THAT ╔ USE A SECTOR INTERLEAVE OF 4 (WHICH IS OPTIMAL) FOR READING THE TRACKS. ╔ THINK THAT OTHER ═╙-─╧╙ FILE COPIER PROGRAM USES AN INTERLEAVE OF 1 (WHICH IS NOT OPTIMAL). ╔ LOSE SOME OF THE RAW PERFORMANCE BECAUSE ╔ COPY THE FILE DATA INTERNALLY ONCE BEFORE OUTPUTTING IT (TO SIMPLIFY SOME OF THE CODE). ╔N A COUPLE OF PLACES YOU WILL NOTICE THAT ┴╙├ TRANSLATION GIVES SLIGHTLY BETTER OR SLIGHTLY WORSE PERFORMANCE THAN ┬╔╬. ╘HIS IS BECAUSE ALTHOUGH SLIGHTLY MORE WORK IS REQUIRED TO TRANSLATE THE CHARACTERS, SLIGHTLY FEWER CHARACTERS WILL HAVE TO BE WRITTEN TO THE ├┬═-─╧╙ FILE, SINCE ╨┼╘╙├╔╔ USES ONLY ├╥ WHERE ═╙-─╧╙ ┴╙├╔╔ USES ├╥ AND ╠╞ TO REPRESENT END-OF-LINE. ╘RANSLATION IS DONE BY USING A TABLE (THAT YOU CAN CHANGE IF YOU WISH). ═ANY ENTRIES IN THIS TABLE CONTAIN A VALUE OF ZERO, WHICH MEANS THAT NO CHARACTER WILL BE OUTPUT ON TRANSLATION. ═OST OF THE CONTROL CHARACTERS AND ALL OF THE CHARACTERS OF VALUE 128 (0X80) OR GREATER ARE THROWN AWAY ON BEING TRANSLATED. ╘HE TABLE IS SET UP SO THAT ├╥ CHARACTERS ARE THROWN AWAY AND THE ╠╞ CHARACTER IS TRANSLATED TO A ├┬═-─╧╙ ├╥ CHARACTER. ╘HUS, BOTH ═╙-─╧╙ ┴╙├╔╔ FILES AND ╒╬╔╪ ┴╙├╔╔ FILES CAN BE TRANSLATED CORRECTLY. 2. ┬╒╥╙╘ ├╧══┴╬─╙ ╘HREE BURST COMMANDS FROM THE 1571/81 DISK DRIVE ┬URST ├OMMAND ╔NSTRUCTION ╙ET ARE REQUIRED TO ALLOW THIS PROGRAM TO READ THE ═╙-─╧╙ DISKS: ╤UERY ─ISK ╞ORMAT, ╙ECTOR ╔NTERLEAVE, AND ╥EAD. ╘HE GRUNGY DETAILS ABOUT ISSUING BURST COMMANDS AND BURST MODE HANDSHAKING ARE COVERED IN ├= ╚ACKING ╔SSUE #3. ╘HE ╤UERY ─ISK ╞ORMAT COMMAND IS USED TO "LOG IN" THE ═╙-─╧╙ DISK. ╘HE ╔NQUIRE ─ISK BURST COMMAND CANNOT BE USED WITH AN ═╙-─╧╙ DISK ON THE 1581 FOR SOME UNKNOWN REASON. ╔ FOUND THIS OUT THE HARD WAY. ╘HE ╤UERY ─ISK ╞ORMAT COMMAND HAS THE FOLLOWING FORMAT: ┬┘╘┼ \ BIT: 7 6 5 4 3 2 1 0 ▄ ╓ALUE -------+--------+-----+-----+-----+-----+-----+-----+-----+------- 0 ▄ 0 ▄ 1 ▄ 0 ▄ 1 ▄ 0 ▄ 1 ▄ 0 ▄ 1 ▄ "╒" 1 ▄ 0 ▄ 0 ▄ 1 ▄ 1 ▄ 0 ▄ 0 ▄ 0 ▄ 0 ▄ "0" 2 ▄ ╞ ▄ ╪ ▄ ╪ ▄ ╙ ▄ 1 ▄ 0 ▄ 1 ▄ ╬ ▄ 10 -------+--------------------------------------------------+------- WHERE THE ╞, ╙, AND ╬ BITS HAVE A VALUE OF 0 FOR OUR PURPOSES. ┴ RESPONSE OF A BURST STATUS BYTE AND SIX OTHER THROW-AWAY BYTES IS GIVEN FROM THE DRIVE. ╘HIS COMMAND TAKES QUITE A LONG TIME TO EXECUTE ON MY 1581 BUT WORKS QUITE QUICKLY ON MY 1571. ┘OU ONLY HAVE TO LOG IN A DISK WHENEVER YOU CHANGE DISKS. ╘HE ╙ECTOR ╔NTERLEAVE COMMAND IS USED TO SET A SOFT INTERLEAVE FOR THE ╥EAD COMMAND. ╔ USE AN INTERLEAVE OF 1 FOR THE 1581 AND AN INTERLEAVE OF 4 FOR THE 1571. ╘HIS MEANS THAT THE ═╙-─╧╙ SECTORS WILL COME FROM 1571 TO THE COMPUTER IN THE FOLLOWING ORDER: 1, 5, 9, 4, 8, 3, 7, 2, 6 (THERE ARE 9 SECTORS PER TRACK ON AN ═╙-─╧╙ DISK (BOTH 3.5" AND 5.25"), NUMBERED FROM 1 TO 9). ╠╥╥ HANDLES THE DATA COMING IN IN THIS ORDER, AND IN STRAIGHT ORDER FROM THE 1581. ╘HE ╙ECTOR ╔NTERLEAVE COMMAND HAS THE FOLLOWING FORMAT, WHERE THE ╫ AND ╬ BITS ARE 0 FOR US: ┬┘╘┼ \ BIT: 7 6 5 4 3 2 1 0 ▄ ╓ALUE -------+--------+-----+-----+-----+-----+-----+-----+-----+------- 0 ▄ 0 ▄ 1 ▄ 0 ▄ 1 ▄ 0 ▄ 1 ▄ 0 ▄ 1 ▄ "╒" 1 ▄ 0 ▄ 0 ▄ 1 ▄ 1 ▄ 0 ▄ 0 ▄ 0 ▄ 0 ▄ "0" 2 ▄ ╫ ▄ ╪ ▄ ╪ ▄ 0 ▄ 1 ▄ 0 ▄ 0 ▄ ╬ ▄ 8 3 ▄ <INTERLEAVE> ▄ 1 OR 4 -------+--------------------------------------------------+------- ╘HE ╥EAD COMMAND IS USED TO TRANSFER THE NINE SECTORS OF A TRACK TO THE COMPUTER IN THE ORDER SPECIFIED BY THE INTERLEAVE. ╘HE FORMAT IS: ┬┘╘┼ \ BIT: 7 6 5 4 3 2 1 0 ▄ ╓ALUE -------+--------+-----+-----+-----+-----+-----+-----+-----+------- 0 ▄ 0 ▄ 1 ▄ 0 ▄ 1 ▄ 0 ▄ 1 ▄ 0 ▄ 1 ▄ "╒" 1 ▄ 0 ▄ 0 ▄ 1 ▄ 1 ▄ 0 ▄ 0 ▄ 0 ▄ 0 ▄ "0" 2 ▄ ╘/╠ ▄ ┼ ▄ ┬/╪ ▄ ╙ ▄ 0 ▄ 0 ▄ 0 ▄ ╬ ▄ 0 OR 16 3 ▄ <TRACK> ▄ ??? 4 ▄ <SECTOR> ▄ 1 5 ▄ <NUMBER OF SECTORS> ▄ 9 -------+--------------------------------------------------+------- ╘HERE ARE A COUPLE OF DIFFERENCES BETWEEN THE 1571 AND 1581 VERSIONS OF THIS COMMAND. ═OST IMPORTANT, THE ╙ BIT (╙IDE OF DISK TO USE) HAS THE OPPOSITE MEANING ON THE TWO DRIVES. ╘HERE'S NO GOOD REASON THAT ╔ KNOW OF FOR THIS INCONSISTENCY. ╘HIS IS THE REASON THAT ╠╥╥ NEEDS TO KNOW WHAT TYPE OF ═╙-─╧╙ DRIVE IT IS DEALING WITH (PLUS INTERLEAVING). ╘HE READ COMMAND RETURNS THE FOLLOWING DATA USING BURST MODE HANDSHAKING: +-------------------+ 0 ▄ ┬URST ╙TATUS ┬YTE ▄ +-------------------+ 1 ▄ ▄ ... + 512 ─ATA ┬YTES ▄ 512 ▄ ▄ +-------------------+ FOR EACH SECTOR TRANSFERRED. ╔F THE ┬URST ╙TATUS ┬YTE INDICATES AN ERROR, THEN THE DATA IS NOT TRANSFERRED AND NONE OF THE FOLLOWING SECTORS ARE EITHER. ╔F THE STATUS BYTE GIVES A "─ISK ├HANGED" ERROR, THEN YOU HAVE TO LOG IN THE DISK WITH THE ╤UERY ─ISK ╞ORMAT COMMAND BEFORE READ WILL WORK PROPERLY. ╘HIS IS ACTUALLY A GOOD FEATURE SINCE IT LETS YOU KNOW ABOUT A DISK CHANGE SO YOU CAN UPDATE ANY DATA STRUCTURES YOU MAY HAVE. ╠╥╥ SIMPLY RE-LOGS IN THE DISK WITHOUT UPDATING ANY DATA STRUCTURES AND RE-TRIES THE FAILED READ OPERATION. 3. ═╙-─╧╙ ─╔╙╦ ╞╧╥═┴╘ ┴N ═╙-─╧╙ DISK IS SEPARATED INTO 4 DIFFERENT PARTS: THE ┬OOT ╙ECTOR, THE ╞┴╘(S), THE ╥OOT ─IRECTORY, AND THE ╞ILE ─ATA ╙ECTORS. ╘HE LOGICAL SECTORS (BLOCKS) OF A DISK ARE NUMBERED FROM 0 TO SOME MAXIMUM NUMBER (1439 FOR A 3.5", 719 FOR A 5.25" ── DISK). ╘HE PHYSICAL LAYOUT AND THE LOGICAL SECTOR NUMBERS TYPICALLY USED BY A 3.5" DISK ARE SHOWN HERE: +-------------------+ 0 ▄ ┬OOT ╙ECTOR ▄ +-------------------+ 1..3 ▄ ╞┴╘ COPY #1 ▄ +-------------------+ 4..6 ▄ ╞┴╘ COPY #2 ▄ +-------------------+ 7..14 ▄ ╥OOT ─IRECTORY ▄ +-------------------+ 15 ▄ ▄ ... ▄ ╞ILE ─ATA ╙ECTORS ▄ 1439 ▄ ▄ +-------------------+ 3.1. ╘╚┼ ┬╧╧╘ ╙┼├╘╧╥ ╘HE ┬OOT ╙ECTOR IS ALWAYS AT LOGICAL SECTOR NUMBER 0. ╔T CONTAINS SOME IMPORTANT INFORMATION ABOUT THE FORMAT OF THE DISK AND IT ALSO CONTAINS CODE TO BOOT AN ═╙-─╧╙ MACHINE FROM. ╫E AREN'T CONCERNED WITH THE BOOTSTRAPPING CODE, BUT THE IMPORTANT VALUES WE NEED TO OBTAIN FROM THE BOOT SECTOR ARE: ┴┬┬╥ ╧╞╞╙┼╘ 1571 1581 ─┼╙├╥╔╨╘╔╧╬ ---- ------ ---- ---- ----------- ├╙ 13 2 2 ├LUSTER SIZE IN SECTORS ╬┬ 14 1 1 ╬UMBER OF BOOT SECTORS ╬╞ 16 2 2 ╬UMBER OF ╞┴╘S ╞╠ 23 2 3 ╞┴╘ SIZE IN SECTORS ─┼ 17 112 112 ╬UMBER OF ROOT DIRECTORY ENTRIES ╘╙ 19,20 720 1440 ╘OTAL ╬UMBER OF SECTORS ╬╙ 24 9 9 ╬UMBER OF SECTORS PER TRACK ╬╚ 26 2 2 ╬UMBER OF SIDES ╘HE 1571 AND 1581 COLUMNS GIVE THE TYPICAL VALUES OF THESE PARAMETERS FOR 5.25" AND 3.5" DISKS. ╘HE ╧╞╞╙┼╘ IS THE ADDRESS OF THE PARAMETER WITHIN THE BOOT SECTOR. ╘HE TOTAL NUMBER OF SECTORS IS GIVEN IN LOW-BYTE, HIGH-BYTE ORDER (SINCE THE 80X86 FAMILY IS LITTLE-ENDIAN LIKE THE 6502 FAMILY). ╞ROM THE ABOVE PARAMETERS, WE CAN DERIVE THE FOLLOWING IMPORTANT PARAMETERS: ┴┬┬╥ ╞╧╥═╒╠┴ 1571 1581 ─┼╙├╥╔╨╘╔╧╬ ---- ------- ---- ---- ----------- ╞1 ╬┬+╬╞*╞╠ 5 7 ╞IRST ROOT DIRECTORY SECTOR ╞╙ ╬┬+╬╞*╞╠+─┼ 12 14 ╞IRST FILE DATA SECTOR NUMBER ╬├ (╘╙-╞╙)/├╙ 354 713 ╘OTAL NUMBER OF FILE CLUSTERS ╠╥╥ IMPOSES A NUMBER OF LIMITS ON THESE PARAMETERS AND WILL ERROR-OUT IF YOU TRY TO USE A DISK THAT IS OUTSIDE OF ╠╥╥'S LIMITS. 3.2. ├╚┼╫╔╬╟ ╘╚┼ ╞┴╘ ═╙-─╧╙ DISKS USE A DATA STRUCTURE CALLED A ╞ILE ┴LLOCATION ╘ABLE (╞┴╘) TO RECORD WHICH CLUSTERS BELONG TO WHICH FILE IN WHAT ORDER AND WHICH BLOCKS ARE FREE. ┴ CLUSTER IS A SET OF CONTIGUOUS SECTORS WHICH ARE ALLOCATED TO FILES AS A GROUP. ╠╥╥ HANDLES CLUSTER SIZES OF 1 AND 2 SECTORS, GIVING A LOGICAL FILE BLOCK SIZE OF 512 OR 1024 BYTES. ╘YPICALLY, A CLUSTER SIZE OF 2 SECTORS IS USED. ╘HE ╞┴╘ IS AN ARRAY OF 12-BIT NUMBERS, WITH AN ENTRY CORRESPONDING TO EACH CLUSTER THAT CAN BE ALLOCATED TO FILES. ╞┴╘ ENTRIES 0 AND 1 ARE RESERVED. ╔F A ╞┴╘ ENTRY CONTAINS A VALUE OF $000, THEN THE CORRESPONDING CLUSTER IS FREE AND CAN BE ALLOCATED TO A FILE; OTHERWISE, THE CLUSTER IS ALLOCATED AND THE ╞┴╘ ENTRY CONTAINS THE NUMBER OF THE ╬┼╪╘ ╞┴╘ ENTRY THAT BELONGS TO THE FILE. ╘HUS, ═╙-─╧╙ FILES ARE STORED IN A SINGLY-LINKED LIST OF CLUSTERS LIKE ├OMMODORE-─╧╙ FILES ARE, EXCEPT THAT THE LINKS ARE NOT IN THE DATA SECTORS BUT RATHER ARE IN THE ╞┴╘. ╘HE POINTER TO THE FIRST ╞┴╘ ENTRY FOR A FILE IS GIVEN IN THE FILE'S DIRECTORY ENTRY. ┴ SPECIAL ╬╒╠╠/╬╔╠ POINTER VALUE OF $╞╞╞ IS USED TO INDICATE THE END OF THE CHAIN OF CLUSTERS ALLOCATED TO A FILE. ╘HIS VALUE IS STORED IN THE ╞┴╘ ENTRY OF THE LAST CLUSTER ALLOCATED TO A FILE (OF COURSE). ├ONSIDER THE FOLLOWING EXAMPLE ╞┴╘: ┼╬╘╥┘ ╓┴╠╒┼ ----- ----- $000 $╞╞╞ $001 $╞╞╞ $002 ▄----$003 <------─IRECTORY ┼NTRY $003 +--> $005----+ $004 $000 ▄ $005 $╞╞╞ <--+ ┼NTRIES 0 AND 1 ARE INSIGNIFICANT SINCE THEY ARE RESERVED. ╙AY THAT A FILE STARTS AT ╞┴╘ ENTRY #2. ╘HEN, IT CONSISTS OF THE FOLLOWING CHAIN OF CLUSTERS: 2, 3, AND 5. ├LUSTER #4 IS FREE. ├LUSTERS CAN BE ALLOCATED TO A FILE IN RANDOM ORDER, BUT IF THEY ARE ALLOCATED CONTIGUOUSLY IN FORWARD ORDER, THEN THE FILE WILL BE ABLE TO BE READ FASTER. ╘HE ╞┴╘ IS SUCH AN IMPORTANT DATA STRUCTURE THAT TYPICALLY TWO COPIES ARE KEPT ON THE DISK INCASE ONE OF THEM SHOULD BECOME CORRUPTED. ╘HE ═╙-─╧╙ DESIGNERS WERE A LITTLE SNEAKY IN STORING THE 12-BIT ╞┴╘ ENTRIES - THEY USED ONLY 12 REAL BITS PER ENTRY. ╔E., THEY STORE TWO ╞┴╘ ENTRIES IN THREE BYTES, WHERE THE TWO ENTRIES SHARE THE TWO NYBBLES OF THE MIDDLE BYTE. ╘HE FOLLOWING DIAGRAM SHOWS HOW THE NYBBLES 1 (HIGH), 2 (MID), AND 3 (LOW) ARE STORED INTO ╞┴╘ ENTRIES ┴ AND ┬: ┬┘╘┼: 0 1 2 +---+---+ +---+---+ +---+---+ ┼╬╘╥┘: ▄ ┴ ▄ ┴ ▄ ▄ ┬ ▄ ┴ ▄ ▄ ┬ ▄ ┬ ▄ ╬┘┬┬╠┼: ▄ 2 ▄ 3 ▄ ▄ 3 ▄ 1 ▄ ▄ 1 ▄ 2 ▄ +---+---+ +---+---+ +---+---+ ┴NYWAY, LET'S JUST SAY IT'S A BIT TRICKY TO EXTRACT THE 12-BIT VALUES FROM THIS COMPRESSED DATA STRUCTURE. ╧N TOP OF THAT, ╔ DON'T THINK THERE IS ANY SAVING IN DISK SPACE RESULTING FROM COMPRESSING THIS STRUCTURE; THEY MIGHT AS WELL HAVE JUST USED A 16-BIT ╞┴╘ (LIKE THEY DO NOWADAYS ON LARGER DISKS). 3.3. ╘╚┼ ╥╧╧╘ ─╔╥┼├╘╧╥┘ ╘HE ROOT DIRECTORY HAS A FIXED SIZE, ALTHOUGH ╔ DON'T THINK THAT SUBDIRECTORIES DO. ╠╥╥ CANNOT ACCESS SUBDIRECTORIES. ┼ACH 512-BYTE SECTOR OF THE ROOT DIRECTORY CONTAINS SIXTEEN 32-BYTE DIRECTORY ENTRIES. ╧NE DIRECTORY ENTRY IS REQUIRED FOR EACH FILE STORED ON THE DISK. ┴ DIRECTORY ENTRY HAS THE FOLLOWING STRUCTURE: ╧╞╞╙┼╘ ╠┼╬ ─┼╙├╥╔╨╘╔╧╬ ------ --- ----------- 0..7 8 ╞ILENAME 8..10 3 ┼XTENSION 11 1 <UNUSED?> 12 1 ┴TTRIBUTES: $10=─IRECTORY, $08=╓OLUME╔D 13..21 9 <UNUSED> 22..25 4 ─ATE 26..27 2 ╙TARTING ╞┴╘ ENTRY NUMBER 28..31 4 ╞ILE LENGTH IN BYTES ╘HE FILENAME AND EXTENSION ARE STORED WITH TRAILING PADDING SPACES. ╔F A DIRECTORY ENTRY IS UNUSED OR DELETED, THEN THE FIRST CHARACTER OF THE FILENAME IS EITHER A $00 OR A $┼5 (229). ╘HIS IS WHY YOU HAVE TO PROVIDE THE FIRST CHARACTER OF A FILENAME IF YOU ARE UNDELETING A FILE ON AN ═╙-─╧╙ MACHINE. ╬OTE THAT THERE IS ENOUGH UNUSED SPACE THAT ═ICROSOFT OR ╔┬═ COULD HAVE DITCHED THE ANNOYING 8+3 CHARACTER FILENAME FORMAT. ╘HE ATTRIBUTES BITS TELL WHETHER THE DIRECTORY ENTRY IS FOR A REGULAR FILE, A SUBDIRECTORY, A DISK VOLUME NAME (IN WHICH CASE THERE IS NO FILE DATA), AND A COUPLE OF OTHER THINGS ╔ CAN'T REMEMBER. ╔'M NOT SURE ABOUT THE EXACT POSITION OR FORMAT OF THE DATE, BUT ╠╥╥ DOESN'T USE IT ANYWAY. ╘HE STARTING ╞┴╘ ENTRY NUMBER AND THE FILE LENGTH ARE STORED IN LOWER-BYTE-FIRST ORDER. 3.4. ╘╚┼ ╞╔╠┼ ─┴╘┴ ╙╨┴├┼ ╘HE RAMAINDER OF THE DISK SPACE IS USED FOR STORING FILE DATA IN CLUSTERS OF 1 OR 2 SECTORS EACH. ╟IVEN A CLUSTER NUMBER (WHICH IS ALSO THE ╞┴╘ ENTRY NUMBER), THE FOLLOWING FORMULA IS USED TO CALCULATE THE STARTING LOGICAL SECTOR NUMBER OF THE CLUSTER: (├LUSTER╬UMBER - 2) * ├LUSTER╙IZE╔N┬LOCKS + ╞IRST╞ILE─ATA╠OGICAL╙ECTOR╬UMBER WHERE "╞IRST╞ILE─ATA╠OGICAL╙ECTOR╬UMBER" IS THE "╞╙" PARAMETER DERIVED EARLIER. ╘HE FOLLOWING CONSECUTIVE LOGICAL SECTOR NUMBERS UP TO THE NUMBER OF SECTORS PER CLUSTER FORM THE REST OF THE CLUSTER. ╬OTE THAT A SINGLE CLUSTER CAN SPAN SECTORS FROM ONE SIDE OF THE DISK TO ANOTHER OR FROM ONE TRACK TO ANOTHER. ╫E PERFORM THE "(├LUSTER╬UMBER - 2)" PORTION OF THE CALCULATION SINCE THE FIRST TWO ╞┴╘ ENTRIES ARE RESERVED. ╙INCE THE ╥EAD BURST COMMAND OF THE 1571/81 WANTS THE SIDE, TRACK, AND SECTOR NUMBER OF A SECTOR RATHER THAN ITS LOGICAL NUMBER, WE ALSO NEED FORMULAE FOR THESE CONVERSIONS: ╘RACK = ╠OGICAL╙ECTOR╬UMBER / 18 ╙ECTOR = ╠OGICAL╙ECTOR╬UMBER % 9 + 1 ╙IDE = (╠OGICAL╙ECTOR╬UMBER / 9) % 2 ╘HESE FORMULAE ARE MORE PROBLEMATIC THAN THE PREVIOUS ONE SINCE THEY REQUIRE DIVISION BY 9 AND 18. ╠╥╥ USES THE METHOD OF REPEATED SUBTRACTION TO PERFROM THE NECESSARY DIVISION (ONLY ONE DIVISION IS NECESSARY). ╘HE ABOVE FORMULAE IMPLY THAT SEQUENTIAL LOGICAL SECTORS ARE STORED ON THE TOP OF THE DISK FIRST AND THEN THE BOTTOM OF THE DISK OF THE SAME TRACK, AND THEN ON THE TOP OF THE NEXT TRACK, ETC. ╘HIS IS A GOOD SECTOR NUMBERING SCHEME (UNLIKE THE ├┬═-─╧╙ SCHEME FOR 1571 SECTORS) SINCE IT IS FASTER TO SWITCH SIDES OF THE DISK THAN IT IS TO SWITCH TRACKS, SO YOU CAN READ THE DISK FASTER. ╧H YEAH, THE WAY THAT YOU KNOW HOW MANY FILE DATA BYTES ARE IN THE LAST CLUSTER OF A FILE CHAIN (THE CLUSTER WITH THE ╬╒╠╠ ╞┴╘ ENTRY) IS TO TAKE THE FILE LENGTH FROM THE DIRECTORY ENTRY AND "MOD" (THE ├ LANGUAGE % OPERATOR) IT WITH THE CLUSTER SIZE. ╧NE SPECIAL CASE IS IF THIS CALCULATION RESULTS IN A ZERO, THEN THE LAST CLUSTER IS COMPLETELY FULL (RATHER THAN COMPLETELY EMPTY AS THE CALCULATION WOULD SUGGEST). ╘HIS CALCULATION IS EASILY DONE IN MACHINE LANGUAGE WITH AN ┴╬─ OPERATION SINCE THE CLUSTER SIZE IS ALWAYS A POWER OF TWO. 4. ╞╔╠┼ ├╧╨┘╔╬╟ ╨┴├╦┴╟┼ ╘HIS SECTION DISCUSSES THE INTERFACE TO AND IMPLEMENTATION OF THE ═╙-─╧╙ FILE COPYING PACKAGE. ╔T IS WRITTEN IN ASSEMBLY LANGUAGE AND IS LOADED INTO MEMORY AT ADDRESS $8000 ON BANK 0 AND REQUIRES ABOUT 13╦ OF MEMORY. ╘HE PACKAGE IS LOADED AT THIS HIGH ADDRESS TO BE OUT OF THE WAY OF THE MAIN ┬┴╙╔├ PROGRAM, EVEN IF ╥┴═─╧╙ IS INSTALLED. 4.1. ╔╬╘┼╥╞┴├┼ ╘HE SUBROUTINE CALL AND PARAMETER PASSING INTERFACE TO THE FILE COPYING PACKAGE IS SUMMARIZED AS FOLLOWS: ┴──╥┼╙╙ ─┼╙├╥╔╨╘╔╧╬ ------- ----------- ╨╦ ╔NIT╨ACKAGE SUBROUTINE ╨╦+3 ╠OAD─IRECTORY SUBROUTINE ╨╦+6 ├OPY╞ILE SUBROUTINE ╨╦+9 TWO-BYTE PACKAGE IDENTIFICATION NUMBER ╨╦+15 ERRNO : ERROR CODE RETURNED ╨╦+16 ═╙-─╧╙ DEVICE NUMBER (8 TO 30) ╨╦+17 ═╙-─╧╙ DEVICE TYPE ($00=1571, $╞╞=1581) ╨╦+18 TWO-BYTE STARTING CLUSTER NUMBER FOR FILE COPYING ╨╦+20 LOW AND MID BYTES OF FILE LENGTH FOR COPYING WHERE "╨╦" IS THE LOAD ADDRESS OF THE PACKAGE. ┴DDITIONAL SUBROUTINE PARAMETERS ARE PASSED IN THE PROCESSOR REGISTERS. ╘HE "╔NIT╨ACKAGE" SUBROUTINE SHOULD BE CALLED WHEN THE PACKAGE IS FIRST INSTALLED, WHENEVER THE ═╙-─╧╙ DEVICE NUMBER IS CHANGED, AND WHENEVER A NEW DISK IS MOUNTED TO INVALIDATE THE INTERNAL TRACK CACHE. ╔T REQUIRES NO PARAMETERS. ╘HE "╠OAD─IRECTORY" SUBROUTINE WILL LOAD THE DIRECTORY, ╞┴╘, AND THE ┬OOT ╙ECTOR PARAMETERS INTO THE INTERNAL MEMORY OF THE PACKAGE FROM THE CURRENT ═╙-─╧╙ DEVICE NUMBER. ╬O (OTHER) INPUT PARAMETERS ARE NEEDED AND THE SUBROUTINE RETURNS A POINTER TO THE DIRECTORY SPACE IN THE .┴┘ REGISTERS AND THE NUMBER OF DIRECTORY ENTRIES IN THE .╪ REGISTER. ╔F AN ERROR OCCURS, THEN THE SUBROUTINE RETURNS WITH THE ├ARRY FLAG SET AND THE ERROR CODE IS AVAILABLE IN THE "ERRNO" INTERFACE VARIABLE. ╘HE DIRECTORY ENTRY DATA IS IN THE DIRECTORY SPACE AS IT WAS READ IN RAW FROM THE DIRECTORY SECTORS ON THE ═╙-─╧╙ DISK. ╘HE "├OPY╞ILE" SUBROUTINE WILL COPY A SINGLE FILE FROM THE ═╙-─╧╙ DISK TO A SPECIFIED ├┬═-╦ERNAL LOGICAL FILE NUMBER (THE ├┬═ FILE MUST ALREADY BE OPENED). ╔F THE ├┬═ LOGICAL FILE NUMBER IS ZERO, THEN THE FILE DATA IS SIMPLY DISCARDED AFTER IT IS READ FROM THE ═╙-─╧╙ FILE. ╘HE STARTING CLUSTER NUMBER OF THE FILE TO COPY AND THE LOW AND MID BYTES OF THE FILE LENGTH ARE PASSED IN THE ╨╦+18 AND ╨╦+20 INTERFACE WORDS. ╘HE TRANSLATION MODE TO USE IS PASSED IN THE .┴ REGISTER ($00=BINARY, $╞╞=ASCII) AND THE ├┬═ LOGICAL FILE NUMBER TO OUTPUT TO IS PASSED IN THE .╪ REGISTER. ╔F AN ERROR OCCURS, THE ROUTINE RETURNS WITH THE ├ARRY FLAG SET AND THE ERROR CODE IN THE "ERRNO" INTERFACE VARIABLE. ╘HERE ARE NO OTHER OUTPUT PARAMETERS. ╬OTE THAT SINCE THE STARTING CLUSTER NUMBER AND LOW-FILE LENGTH OF THE FILE TO BE COPIED ARE REQUIRED RATHER THAN THE FILENAME, IT IS THE RESPONSIBILITY OF THE FRONT-END APPLICATION PROGRAM TO DIG THROUGH THE RAW DIRECTORY SECTOR DATA TO GET THIS INFORMATION. ╘HE APPLICATION MUST ALSO OPEN THE ├OMMODORE-─╧╙ FILE OF WHATEVER FILETYPE ON WHATEVER DEVICE IS REQUIRED; THE PACKAGE DOES NOT NEED TO KNOW THE ├OMMODORE-─╧╙ DEVICE NUMBER. ╘HE ═╙-─╧╙ DEVICE NUMBER AND DEVICE TYPE INTERFACE VARIABLES ALLOW YOU TO SET THE ═╙-─╧╙ DRIVE AND THE PACKAGE IDENTIFICATION NUMBER ALLOWS THE APPLICATION PROGRAM TO CHECK IF THE PACKAGE IS ALREADY LOADED INTO MEMORY SO THAT IT ONLY HAS TO LOAD THE PACKAGE THE FIRST TIME THE APPLICATION IS RUN AND NOT ON RE-RUNS. ╘HE IDENTIFICATION SEQUENCE IS A VALUE OF $├┬ FOLLOWED BY A VALUE OF 131. 4.2. ╔═╨╠┼═┼╬╘┴╘╔╧╬ ╘HIS SECTION PRESENTS THE CODE THAT IMPLEMENTS THE ═╙-─╧╙ FILE READING PACKAGE. ╔T IS HERE IN A SPECIAL FORM; EACH CODE LINE IS PRECEDED BY A FEW SPECIAL CHARACTERS AND THE LINE NUMBER. ╘HE SPECIAL CHARACTERS ARE THERE TO ALLOW YOU TO EASILY EXTRACT THE ASSEMBLER CODE FROM THE REST OF THIS MAGAZINE (AND ALL OF MY UGLY COMMENTS). ╧N A ╒NIX SYSTEM, ALL YOU HAVE TO DO IS EXECUTE THE FOLLOWING COMMAND LINE (SUBSTITUTE FILENAMES AS APPROPRIATE): GREP '^\.%...\!' ╚ACK4 ▄ SED 'S/^.%...\!..//' ▄ SED 'S/.%...\!//' >LRR.S ┘OU'LL NOTICE THAT THE INITIAL COMMENT LINES HERE WERE AN AFTERTHOUGHT. .%000! ;╠ITTLE ╥ED ╥EADER ═╙-─╧╙ FILE COPIER PROGRAM .%000! ;WRITTEN 92/10/03 BY ├RAIG ┬RUCE FOR ├= ╚ACKING ╬ET ═AGAZINE .%000! ╘HE CODE IS WRITTEN FOR THE ┬UDDY ASSEMBLER AND HERE ARE A COUPLE SETUP DIRECTIVES. ╬OTE THAT MY COMMENTS COME BEFORE THE SECTION OF CODE. .%001! .ORG $8000 .%002! .OBJ "@:LRR.BIN" .%003! .%004! ;====JUMP TABLE AND PARAMETERS INTERFACE ==== .%005! .%006! JMP INIT╨ACKAGE .%007! JMP LOAD─IRECTORY .%008! JMP COPY╞ILE .%009! .%010! .BYTE $CB,131 ;IDENTIFICATION .%011! .BYTE 0,0,0,0 .%012! ╘HESE VARIABLES ARE INCLUDED IN THE PACKAGE PROGRAM SPACE TO MINIMIZE UNWANTED INTERACTION WITH OTHER PROGRAMS LOADED AT THE SAME TIME, SUCH AS THE ╥┴═─╧╙ DEVICE DRIVER. .%013! ERRNO .BUF 1 ;(LOCATION PK+15) .%014! SOURCE─EVICE .BUF 1 .%015! SOURCE╘YPE .BUF 1 ;$00=1571, $FF=1581 .%016! START├LUSTER .BUF 2 .%017! LEN═╠ .BUF 2 ;LENGTH MEDIUM AND LOW BYTES .%018! .%019! ;====GLOBAL DECLARAIONS==== .%020! .%021! KERNEL╠ISTEN = $FFB1 .%022! KERNEL╙ECOND = $FF93 .%023! KERNEL╒NLSN = $FFAE .%024! KERNEL┴CPTR = $FFA2 .%025! KERNEL├IOUT = $FFA8 .%026! KERNEL╙PINP = $FF47 .%027! KERNEL├HKOUT = $FFC9 .%028! KERNEL├LRCHN = $FFCC .%029! KERNEL├HROUT = $FFD2 .%030! .%031! ST = $D0 .%032! CIA├LOCK = $DD00 .%033! CIA╞LAGS = $DC0D .%034! CIA─ATA = $DC0C .%035! ╘HESE ARE THE PARAMETERS AND DERIVED PARAMETERS FROM THE BOOT SECTOR. ╘HEY ARE KEPT IN THE PROGRAM SPACE TO AVOID INTERACTIONS. .%036! CLUSTER┬LOCK├OUNT .BUF 1 ;1 OR 2 .%037! FAT┬LOCKS .BUF 1 ;UP TO 3 .%038! ROOT─IR┬LOCKS .BUF 1 ;UP TO 8 .%039! ROOT─IR┼NTRIES .BUF 1 ;UP TO 128 .%040! TOTAL╙ECTORS .BUF 2 ;UP TO 1440 .%041! FIRST╞ILE┬LOCK .BUF 1 .%042! FIRST╥OOT─IR┬LOCK .BUF 1 .%043! FILE├LUSTER├OUNT .BUF 2 .%044! ╘HE CYLINDER (TRACK) AND SIDE THAT IS CURRENTLY STORED IN THE TRACH CACHE. .%045! BUF├YLINDER .BUF 1 .%046! BUF╙IDE .BUF 1 .%047! FORMAT╨ARMS .BUF 6 .%048! ╘HIS PACKAGE IS SPLIT INTO A NUMBER OF LEVELS. ╘HIS LEVEL INTERFACES WITH THE ╦ERNAL SERIAL BUS ROUTINES AND THE BURST COMMAND PROTOCOL OF THE DISK DRIVES. .%049! ;====HARDWARE LEVEL==== .%050! ├ONNECT TO THE ═╙-─╧╙ DEVICE AND SEND THE "╒0" BURST COMMAND PREFIX AND THE BURST COMMAND BYTE. .%051! SEND╒0 = * ;( .┴=BURST├OMMAND├ODE ) : .├╙=ERR .%052! PHA .%053! LDA #0 .%054! STA ST .%055! LDA SOURCE─EVICE .%056! JSR KERNEL╠ISTEN .%057! LDA #$6F .%058! JSR KERNEL╙ECOND .%059! LDA #"U" .%060! JSR KERNEL├IOUT .%061! BIT ST .%062! BMI SEND╒0┼RROR .%063! LDA #"0" .%064! JSR KERNEL├IOUT .%065! PLA .%066! JSR KERNEL├IOUT .%067! BIT ST .%068! BMI SEND╒0┼RROR .%069! CLC .%070! RTS .%071! .%072! SEND╒0┼RROR = * .%073! LDA #5 .%074! STA ERRNO .%075! SEC .%076! RTS .%077! ╘OGGLE THE "─ATA ┴CCEPTED / ╥EADY ╞OR ═ORE" CLOCK SIGNAL FOR THE BURST TRANSFER PROTOCOL. .%078! TOGGLE├LOCK = * .%079! LDA CIA├LOCK .%080! EOR #$10 .%081! STA CIA├LOCK .%082! RTS .%083! ╫AIT FOR A BURST BYTE TO ARRIVE IN THE SERIAL DATA REGISTER OF ├╔┴#1 FROM THE FAST SERIAL BUS. .%084! SERIAL╫AIT = * .%085! LDA #$08 .%086! - BIT CIA╞LAGS .%087! BEQ - .%088! RTS .%089! ╫AIT FOR AND GET A BURST BYTE FROM THE FAST SERIAL BUS, AND SEND THE "─ATA ┴CCEPTED" SIGNAL. .%090! GET┬URST┬YTE = * .%091! JSR SERIAL╫AIT .%092! LDX CIA─ATA .%093! JSR TOGGLE├LOCK .%094! TXA .%095! RTS .%096! ╙END THE BURST COMMANDS TO "LOG IN" THE ═╙-─╧╙ DISK AND SET THE ╥EAD SECTOR INTERLEAVE FACTOR. .%097! MOUNT─ISK = * ;() : .├╙=ERR .%098! LDA #%00011010 .%099! JSR SEND╒0 .%100! BCC + .%101! RTS .%102! + JSR KERNEL╒NLSN .%103! BIT ST .%104! BMI SEND╒0┼RROR .%105! CLC .%106! JSR KERNEL╙PINP .%107! BIT CIA╞LAGS .%108! JSR TOGGLE├LOCK .%109! JSR GET┬URST┬YTE .%110! STA ERRNO .%111! AND #$0F .%112! CMP #2 .%113! BCS MOUNT┼XIT ╟RAB THE THROW-AWAY PARAMETERS FROM THE MOUNT OPERATION. .%114! LDY #0 .%115! - JSR GET┬URST┬YTE .%116! STA FORMAT╨ARMS,Y .%117! INY .%118! CPY #6 .%119! BCC - .%120! CLC ╙ET THE SECTOR INTERLEAVE TO 1 FOR A 1581 OR 4 FOR A 1571. .%121! ;** SET INTERLEAVE .%122! LDA #%00001000 .%123! JSR SEND╒0 .%124! BCC + .%125! RTS .%126! + LDA #1 ;INTERLEAVE OF 1 FOR 1581 .%127! BIT SOURCE╘YPE .%128! BMI + .%129! LDA #4 ;INTERLEAVE OF 4 FOR 1571 .%130! + JSR KERNEL├IOUT .%131! JSR KERNEL╒NLSN .%132! MOUNT┼XIT = * .%133! RTS .%134! ╥EAD ALL OF THE SECTORS OF A GIVEN TRACK INTO THE TRACK CACHE. .%135! BUFPTR = 2 .%136! SECNUM = 4 .%137! .%138! READ╘RACK = * ;( .┴=CYLINDER, .╪=SIDE ) : TRACKBUF, .├╙=ERR .%139! PHA .%140! TXA ╟ET THE SIDE AND PUT IT INTO THE COMMAND BYTE. ╥EMEMBER THAT WE HAVE TO FLIP THE SIDE BIT FOR A 1581. .%141! AND #$01 .%142! ASL .%143! ASL .%144! ASL .%145! ASL .%146! BIT SOURCE╘YPE .%147! BPL + .%148! EOR #$10 .%149! + JSR SEND╒0 .%150! BCC + .%151! RTS .%152! + PLA ;CYLINDER NUMBER .%153! JSR KERNEL├IOUT .%154! LDA #1 ;START SECTOR NUMBER .%155! JSR KERNEL├IOUT .%156! LDA #9 ;SECTOR COUNT .%157! JSR KERNEL├IOUT .%158! JSR KERNEL╒NLSN ╨REPARE TO RECEIVE THE TRACK DATA. .%159! SEI .%160! CLC .%161! JSR KERNEL╙PINP .%162! BIT CIA╞LAGS .%163! JSR TOGGLE├LOCK .%164! LDA #<TRACKBUF .%165! LDY #>TRACKBUF .%166! STA BUFPTR .%167! STY BUFPTR+1 ╟ET THE SECTOR DATA FOR EACH OF THE 9 SECTORS OF THE TRACK. .%168! LDA #0 .%169! STA SECNUM .%170! - BIT SOURCE╘YPE .%171! BMI + ╔F WE ARE DEALING WITH A 1571, WE HAVE TO SET THE BUFFER POINTER FOR THE NEXT SECTOR, TAKING INTO ACCOUNT THE SOFT INTERLEAVE OF 4. .%172! JSR GET1571┬UF╨TR .%173! + JSR READ╙ECTOR .%174! BCS TRACK┼XIT .%175! INC SECNUM .%176! LDA SECNUM .%177! CMP #9 .%178! BCC - .%179! CLC .%180! TRACK┼XIT = * .%181! CLI .%182! RTS .%183! ╟ET THE BUFFER POINTER FOR THE NEXT 1571 SECTOR. .%184! GET1571┬UF╨TR = * .%185! LDA #<TRACKBUF .%186! STA BUFPTR .%187! LDX SECNUM .%188! CLC .%189! LDA #>TRACKBUF .%190! ADC BUFPTR1571,X .%191! STA BUFPTR+1 .%192! RTS .%193! .%194! BUFPTR1571 = * .%195! .BYTE 0,8,16,6,14,4,12,2,10 .%196! ╥EAD AN INDIVIDUAL SECTOR INTO MEMORY AT THE SPECIFIED ADDRESS. .%197! READ╙ECTOR = * ;( BUFPTR ) : .├╙=ERR ╟ET AND CHECK THE BURST STATUS BYTE FOR ERRORS. .%198! JSR GET┬URST┬YTE .%199! STA ERRNO .%200! AND #$0F .%201! CMP #2 .%202! BCC + .%203! RTS .%204! + LDX #2 .%205! LDY #0 .%206! ╥ECEIVE THE 512 SECTOR DATA BYTES INTO MEMORY. .%207! READ┬YTE = * .%208! LDA #$08 .%209! - BIT CIA╞LAGS .%210! BEQ - .%211! LDA CIA├LOCK .%212! EOR #$10 .%213! STA CIA├LOCK .%214! LDA CIA─ATA .%215! STA (BUFPTR),Y .%216! INY .%217! BNE READ┬YTE .%218! INC BUFPTR+1 .%219! DEX .%220! BNE READ┬YTE .%221! RTS .%222! ╘HIS NEXT LEVEL OF ROUTINES DEALS WITH LOGICAL SECTORS AND THE TRACK CACHE RATHER THAN WITH HARDWARE. .%223! ;====LOGICAL SECTOR LEVEL==== .%224! ╔NVALIDATE THE TRACK CACHE IF THE ═╙-─╧╙ DRIVE NUMBER IS CHANGED OR IF A NEW DISK IS INSERTED. ╘HIS ROUTINE HAS TO ESTABLISH A ╥┴═ CONFIGURATION OF $0┼ SINCE IT WILL BE CALLED FROM ╥┴═0. ├ONFIGURATION $0┼ GIVES ╥┴═0 FROM $0000 TO $┬╞╞╞, ╦ERNAL ╥╧═ FROM $├000 TO $╞╞╞╞, AND THE ╔/╧ SPACE OVER THE ╦ERNAL FROM $─000 TO $─╞╞╞. ╘HIS CONFIGURATION IS SET BY ALL APPLICATION INTERFACE SUBROUTINES. .%225! INIT╨ACKAGE = * .%226! LDA #$0E .%227! STA $FF00 .%228! LDA #$FF .%229! STA BUF├YLINDER .%230! STA BUF╙IDE .%231! CLC .%232! RTS .%233! ╠OCATE A SECTOR (BLOCK) IN THE TRACK CACHE, OR READ THE CORRESPONDING PHYSICAL TRACK INTO THE TRACK CACHE IF NECESSARY. ╘HIS ROUTINE ACCEPTS THE CYLINDER, SIDE, AND SECTOR NUMBERS OF THE BLOCK. .%234! SECTOR╙AVE = 5 .%235! .%236! READ┬LOCK = * ;( .┴=CYLINDER,.╪=SIDE,.┘=SECTOR ) : .┴┘=BLK╨TR,.├╙=ERR ├HECK IF THE CORRECT TRACK IS IN THE TRACK CACHE. .%237! CMP BUF├YLINDER .%238! BNE READ┬LOCK╨HYSICAL .%239! CPX BUF╙IDE .%240! BNE READ┬LOCK╨HYSICAL ╔F SO, THEN LOCATE THE SECTOR'S ADDRESS AND RETURN THAT. .%241! DEY .%242! TYA .%243! ASL .%244! CLC .%245! ADC #>TRACKBUF .%246! TAY .%247! LDA #<TRACKBUF .%248! CLC .%249! RTS .%250! ╚ERE, WE HAVE TO READ THE PHYSICAL TRACK INTO THE TRACK CACHE. ╫E SAVE THE INPUT PARAMETERS AND CALL THE HARDWARE-LEVEL TRACK-READING ROUTINE. .%251! READ┬LOCK╨HYSICAL = * .%252! STA BUF├YLINDER .%253! STX BUF╙IDE .%254! STY SECTOR╙AVE .%255! JSR READ╘RACK ├HECK FOR ERRORS. .%256! BCC READ┬LOCK╨HYSICAL╧K .%257! LDA ERRNO .%258! AND #$0F .%259! CMP #11 ;DISK CHANGE .%260! BEQ + .%261! SEC .%262! RTS ╔F THE ERROR THAT HAPPENED IS A "─ISK ├HANGE" ERROR, THEN MOUNT THE DISK AND TRY TO READ THE PHYSICAL TRACK AGAIN. .%263! + JSR MOUNT─ISK .%264! LDA BUF├YLINDER .%265! LDX BUF╙IDE .%266! LDY SECTOR╙AVE .%267! BCC READ┬LOCK╨HYSICAL .%268! RTS .%269! ╚ERE, THE PHYSICAL TRACK HAS BEEN READ INTO THE TRACK CACHE OK, SO WE RECOVER THE ORIGINAL INPUT PARAMETERS AND TRY THE TOP OF THE ROUTINE AGAIN. .%270! READ┬LOCK╨HYSICAL╧K = * .%271! LDA BUF├YLINDER .%272! LDX BUF╙IDE .%273! LDY SECTOR╙AVE .%274! JMP READ┬LOCK .%275! ─IVIDE THE GIVEN NUMBER BY 18. ╘HIS IS NEEDED FOR THE CALCULATIONS TO CONVERT A LOGICAL SECTOR NUMBER TO THE CORRESPONDING PHYSICAL CYLINDER, SIDE, AND SECTOR NUMBERS THAT THE LOWER-LEVEL ROUTINES REQUIRE. ╘HE METHOD OF REPEATED SUBTRACTION IS USED. ╘HIS ROUTINE WOULD PROBABLY WORK FASTER IF WE TRIED TO REPEATEDLY SUBTRACT 360 (18*20) AT THE TOP, BUT ╔ DIDN'T BOTHER. .%276! DIVIDE┬Y18 = * ;( .┴┘=NUMBER ) : .┴=QUOTIENT, .┘=REMAINDER .%277! ;** COULD REPEATEDLY SUBTRACT 360 HERE .%278! LDX #$FF .%279! - INX .%280! SEC .%281! SBC #18 .%282! BCS - .%283! DEY .%284! BPL - .%285! CLC .%286! ADC #18 .%287! INY .%288! TAY .%289! TXA .%290! RTS .%291! ├ONVERT THE GIVEN LOGICAL BLOCK NUMBER TO THE CORRESPONDING PHYSICAL CYLINDER, SIDE, AND SECTOR NUMBERS. ╘HIS ROUTINE FOLLOWS THE FORMULAE GIVEN EARLIER WITH A FEW SIMPLIFYING TRICKS. .%292! CONVERT╠OGICAL┬LOCK╬UM = * ;( .┴┘=BLOCK╬UM ) : .┴=CYL, .╪=SIDE, .┘=SEC .%293! JSR DIVIDE┬Y18 .%294! LDX #0 .%295! CPY #9 .%296! BCC + .%297! PHA .%298! TYA .%299! SBC #9 .%300! TAY .%301! PLA .%302! LDX #1 .%303! + INY .%304! RTS .%305! ├OPY A SEQUENTIAL GROUP OF LOGICAL SECTORS INTO MEMORY. ╘HIS ROUTINE IS USED BY THE DIRECTORY LOADING ROUTINE TO LOAD THE ╞┴╘ AND ╥OOT ─IRECTORY, AND IS USED BY THE CLUSTER READING ROUTINE TO RETRIEVE ALL OF THE BLOCKS OF A CLUSTER. ┴FTER THE GIVEN STARTING LOGICAL SECTOR NUMBER IS CONVERTED INTO ITS PHYSICAL CYLINDER, SIDE, AND SECTOR EQUIVALENT, THE PHYSICAL VALUES ARE INCREMENTED TO GET THE ADDRESS OF SUCCESSIVE SECTORS OF THE GROUP. ╘HIS AVOIDS THE OVERHEAD OF THE LOGICAL TO PHYSICAL CONVERSION. ╤UITE A NUMBER OF TEMPORARIES ARE NEEDED. .%306! DEST╨TR = 6 .%307! CUR├YLINDER = 8 .%308! CUR╙IDE = 9 .%309! CUR╙ECTOR = 10 .%310! BLOCK├OUNTDOWN = 11 .%311! SOURCE╨TR = 12 .%312! .%313! COPY┬LOCKS = * ;( .┴┘=START┬LOCK, .╪=BLOCK├OUNT, ($6)=DEST ) : .├╙=ERR .%314! STX BLOCK├OUNTDOWN .%315! JSR CONVERT╠OGICAL┬LOCK╬UM .%316! STA CUR├YLINDER .%317! STX CUR╙IDE .%318! STY CUR╙ECTOR .%319! .%320! COPY┬LOCK╠OOP = * .%321! LDA CUR├YLINDER .%322! LDX CUR╙IDE .%323! LDY CUR╙ECTOR .%324! JSR READ┬LOCK .%325! BCC + .%326! RTS .%327! + STA SOURCE╨TR .%328! STY SOURCE╨TR+1 .%329! LDX #2 .%330! LDY #0 ╚ERE ╔ UNROLL THE COPYING LOOP A LITTLE BIT TO CUT THE OVERHEAD OF THE BRANCH INSTRUCTION IN HALF. (┴ CYCLE SAVED... YOU KNOW). .%331! - LDA (SOURCE╨TR),Y .%332! STA (DEST╨TR),Y .%333! INY .%334! LDA (SOURCE╨TR),Y .%335! STA (DEST╨TR),Y .%336! INY .%337! BNE - .%338! INC SOURCE╨TR+1 .%339! INC DEST╨TR+1 .%340! DEX .%341! BNE - ╔NCREMENT THE CYLINDER, SIDE, SECTOR VALUES. .%342! INC CUR╙ECTOR .%343! LDA CUR╙ECTOR .%344! CMP #10 .%345! BCC + .%346! LDA #1 .%347! STA CUR╙ECTOR .%348! INC CUR╙IDE .%349! LDA CUR╙IDE .%350! CMP #2 .%351! BCC + .%352! LDA #0 .%353! STA CUR╙IDE .%354! INC CUR├YLINDER .%355! + DEC BLOCK├OUNTDOWN .%356! BNE COPY┬LOCK╠OOP .%357! CLC .%358! RTS .%359! ╥EAD A CLUSTER INTO THE ├LUSTER ┬UFFER, GIVEN THE CLUSTER NUMBER. ╘HE CLUSTER NUMBER IS CONVERTED TO A LOGICAL SECTOR NUMBER AND THEN THE SECTOR COPYING ROUTINE IS CALLED. ╘HE FORMULA GIVEN EARLIER IS USED FOR THE CONVERSION. .%360! READ├LUSTER = * ;( .┴┘=CLUSTER╬UMBER ) : CLUSTER┬UF, .├╙=ERR .%361! ;** CONVERT CLUSTER NUMBER TO LOGICAL BLOCK NUMBER .%362! SEC .%363! SBC #2 .%364! BCS + .%365! DEY .%366! + LDX CLUSTER┬LOCK├OUNT .%367! CPX #1 .%368! BEQ + .%369! ASL .%370! STY 7 .%371! ROL 7 .%372! LDY 7 .%373! + CLC .%374! ADC FIRST╞ILE┬LOCK .%375! BCC + .%376! INY .%377! .%378! ;** READ LOGICAL BLOCKS COMPRISING CLUSTER .%379! + LDX #<CLUSTER┬UF .%380! STX 6 .%381! LDX #>CLUSTER┬UF .%382! STX 7 .%383! LDX CLUSTER┬LOCK├OUNT .%384! JMP COPY┬LOCKS .%385! ╘HIS NEXT LEVEL OF ROUTINES DEAL WITH THE DATA STRUCTURES OF THE ═╙-─╧╙ DISK FORMAT. .%386! ;====═╙-─╧╙ FORMAT LEVEL==== .%387! .%388! BOOT┬LOCK = 2 .%389! ╥EAD THE DISK FORMAT PARAMETERS, DIRECTORY, AND ╞┴╘ INTO MEMORY. .%390! LOAD─IRECTORY = * ;( ) : .┴┘=DIRBUF, .╪=DIR┼NTRIES, .├╙=ERR .%391! LDA #$0E .%392! STA $FF00 .%393! ╥EAD THE BOOT SECTOR AND EXTRACT THE PARAMETERS. .%394! ;** GET PARAMETERS FROM BOOT SECTOR .%395! LDA #0 .%396! LDY #0 .%397! JSR CONVERT╠OGICAL┬LOCK╬UM .%398! JSR READ┬LOCK .%399! BCC + .%400! RTS .%401! + STA BOOT┬LOCK .%402! STY BOOT┬LOCK+1 .%403! LDY #13 ;GET CLUSTER SIZE .%404! LDA (BOOT┬LOCK),Y .%405! STA CLUSTER┬LOCK├OUNT .%406! CMP #3 .%407! BCC + .%408! ╔F A DISK PARAMETER IS FOUND TO EXCEED THE LIMITS OF ╠╥╥, ERROR CODE #60 IS RETURNED. .%409! INVALID╨ARMS = * .%410! LDA #60 .%411! STA ERRNO .%412! SEC .%413! RTS .%414! .%415! + LDY #16 ;CHECK ╞┴╘ REPLICATION COUNT, MUST BE 2 .%416! LDA (BOOT┬LOCK),Y .%417! CMP #2 .%418! BNE INVALID╨ARMS .%419! LDY #22 ;GET ╞┴╘ SIZE IN SECTORS .%420! LDA (BOOT┬LOCK),Y .%421! STA FAT┬LOCKS .%422! CMP #4 .%423! BCS INVALID╨ARMS .%424! LDY #17 ;GET DIRECTORY SIZE .%425! LDA (BOOT┬LOCK),Y .%426! STA ROOT─IR┼NTRIES .%427! CMP #129 .%428! BCS INVALID╨ARMS .%429! LSR .%430! LSR .%431! LSR .%432! LSR .%433! STA ROOT─IR┬LOCKS .%434! LDY #19 ;GET TOTAL SECTOR COUNT .%435! LDA (BOOT┬LOCK),Y .%436! STA TOTAL╙ECTORS .%437! INY .%438! LDA (BOOT┬LOCK),Y .%439! STA TOTAL╙ECTORS+1 .%440! LDY #24 ;CHECK SECTORS PER TRACK, MUST BE 9 .%441! LDA (BOOT┬LOCK),Y .%442! CMP #9 .%443! BNE INVALID╨ARMS .%444! LDY #26 .%445! LDA (BOOT┬LOCK),Y .%446! CMP #2 ;CHECK NUMBER OF SIDES, MUST BE 2 .%447! BNE INVALID╨ARMS .%448! LDY #14 ;CHECK NUMBER OF BOOT SECTORS, MUST BE 1 .%449! LDA (BOOT┬LOCK),Y .%450! CMP #1 .%451! BNE INVALID╨ARMS .%452! ├ALCULATE THE DERIVED PARAMETERS. .%453! ;** GET DERIVED PARAMETERS .%454! LDA FAT┬LOCKS ;FIRST ROOT DIRECTORY SECTOR .%455! ASL .%456! CLC .%457! ADC #1 .%458! STA FIRST╥OOT─IR┬LOCK .%459! CLC ;FIRST FILE SECTOR .%460! ADC ROOT─IR┬LOCKS .%461! STA FIRST╞ILE┬LOCK .%462! LDA TOTAL╙ECTORS ;NUMBER OF FILE CLUSTERS .%463! LDY TOTAL╙ECTORS+1 .%464! SEC .%465! SBC FIRST╞ILE┬LOCK .%466! BCS + .%467! DEY .%468! + STA FILE├LUSTER├OUNT .%469! STY FILE├LUSTER├OUNT+1 .%470! LDA CLUSTER┬LOCK├OUNT .%471! CMP #2 .%472! BNE + .%473! LSR FILE├LUSTER├OUNT+1 .%474! ROR FILE├LUSTER├OUNT .%475! ╟EE, ╔ HAVE MORE COMMENTS EMBEDDED IN THE CODE THAN ╔ DID LAST ISSUE. .%476! ;** LOAD ╞┴╘ .%477! + LDA #<FATBUF .%478! LDY #>FATBUF .%479! STA 6 .%480! STY 7 .%481! LDA #1 .%482! LDY #0 .%483! LDX FAT┬LOCKS .%484! JSR COPY┬LOCKS .%485! BCC + .%486! RTS .%487! .%488! ;** LOAD ACTUAL DIRECTORY .%489! + LDA #<DIRBUF .%490! LDY #>DIRBUF .%491! STA 6 .%492! STY 7 .%493! LDA FIRST╥OOT─IR┬LOCK .%494! LDY #0 .%495! LDX ROOT─IR┬LOCKS .%496! JSR COPY┬LOCKS .%497! BCC + .%498! RTS .%499! + LDA #<DIRBUF .%500! LDY #>DIRBUF .%501! LDX ROOT─IR┼NTRIES .%502! CLC .%503! RTS .%504! ╘HIS ROUTINE LOCATES THE GIVEN ╞┴╘ TABLE ENTRY NUMBER AND RETURNS THE VALUE STORED IN IT. ╙OME WORK IS NEEDED TO DEAL WITH THE 12-BIT COMPRESSED DATA STRUCTURE. .%505! ENTRY┴DDR = 2 .%506! ENTRY╫ORK = 4 .%507! ENTRY┬ITS = 5 .%508! ENTRY─ATA0 = 6 .%509! ENTRY─ATA1 = 7 .%510! ENTRY─ATA2 = 8 .%511! .%512! GET╞AT┼NTRY = * ;( .┴┘=FAT┼NTRY╬UMBER ) : .┴┘=FAT┼NTRY╓ALUE .%513! STA ENTRY┬ITS ─IVIDE THE ╞┴╘ ENTRY NUMBER BY TWO AND MULTIPLY BY THREE BECAUSE TWO ╞┴╘ ENTRIES ARE STORED IN THREE BYTES. ╘HEN ADD THE ╞┴╘ BASE ADDRESS AND WE HAVE THE ADDRESS OF THE THREE BYTES THAT CONTAIN THE ╞┴╘ ENTRY WE ARE INTERESTED IN. ╔ RETRIEVE THE THREE BYTES INTO ZERO-PAGE MEMORY FOR EASY MANIPULATION. .%514! ;** DIVIDE BY TWO .%515! STY ENTRY┴DDR+1 .%516! LSR ENTRY┴DDR+1 .%517! ROR .%518! .%519! ;** TIMES THREE .%520! STA ENTRY╫ORK .%521! LDX ENTRY┴DDR+1 .%522! ASL .%523! ROL ENTRY┴DDR+1 .%524! CLC .%525! ADC ENTRY╫ORK .%526! STA ENTRY┴DDR .%527! TXA .%528! ADC ENTRY┴DDR+1 .%529! STA ENTRY┴DDR+1 .%530! .%531! ;** ADD BASE, GET DATA .%532! CLC .%533! LDA ENTRY┴DDR .%534! ADC #<FATBUF .%535! STA ENTRY┴DDR .%536! LDA ENTRY┴DDR+1 .%537! ADC #>FATBUF .%538! STA ENTRY┴DDR+1 .%539! LDY #2 .%540! - LDA (ENTRY┴DDR),Y .%541! STA ENTRY─ATA0,Y .%542! DEY .%543! BPL - .%544! LDA ENTRY┬ITS .%545! AND #1 .%546! BNE + .%547! ╔F THE ORIGINAL GIVEN ╞┴╘ ENTRY NUMBER IS EVEN, THEN WE WANT THE FIRST 12-BIT COMPRESSED FIELD. ╘HE NYBBLES ARE EXTRACTED ACCORDING TO THE DIAGRAM SHOWN EARLIER. .%548! ;** CASE 1: FIRST 12-BIT CLUSTER .%549! LDA ENTRY─ATA1 .%550! AND #$0F .%551! TAY .%552! LDA ENTRY─ATA0 .%553! RTS .%554! ╧THERWISE, WE WANT THE SECOND 12-BIT FIELD. .%555! ;** CASE 2: SECOND 12-BIT CLUSTER .%556! + LDA ENTRY─ATA1 .%557! LDX #4 .%558! - LSR ENTRY─ATA2 .%559! ROR .%560! DEX .%561! BNE - .%562! LDY ENTRY─ATA2 .%563! RTS .%564! ╞INALLY, THIS IS THE FILE COPYING LEVEL. ╔T DEALS WITH READING THE CLUSTERS OF ═╙-─╧╙ FILES AND COPYING THE DATA THEY CONTAIN TO THE ALREADY-OPEN ├┬═ ╦ERNAL FILE, POSSIBLY WITH ┴╙├╔╔-TO-╨┼╘╙├╔╔ TRANSLATION. .%565! ;====FILE COPY LEVEL==== .%566! .%567! TRANS═ODE = 14 .%568! LFN = 15 .%569! CBM─ATA╨TR = $60 .%570! CBM─ATA╠EN = $62 .%571! CLUSTER = $64 .%572! ├OPY THE GIVEN CLUSTER TO THE ├┬═ OUTPUT FILE. ╘HIS ROUTINE FETCHES THE NEXT CLUSTER OF THE FILE FOR THE NEXT TIME THIS ROUTINE IS CALLED, AND IF IT HITS THE ╬╒╠╠ POINTER OF THE LAST CLUSTER OF A FILE, IT ADJUSTS THE NUMBER OF VALID FILE DATA BYTES THE CURRENT CLUSTER CONTAINS TO ╞ILE╠ENGTH % ├LUSTER╠ENGTH (SEE NOTE BELOW). .%573! COPY╞ILE├LUSTER = * ;( CLUSTER, LFN, TRANS═ODE ) : .├╙=ERR ╥EAD THE CLUSTER AND SETUP TO COPY THE WHOLE CLUSTER TO THE ├┬═ FILE. .%574! LDA CLUSTER .%575! LDY CLUSTER+1 .%576! JSR READ├LUSTER .%577! BCC + .%578! RTS .%579! + LDA #<CLUSTER┬UF .%580! LDY #>CLUSTER┬UF .%581! STA CBM─ATA╨TR .%582! STY CBM─ATA╨TR+1 .%583! LDA #0 .%584! STA CBM─ATA╠EN .%585! LDA CLUSTER┬LOCK├OUNT .%586! ASL .%587! STA CBM─ATA╠EN+1 .%588! ╞ETCH THE NEXT CLUSTER NUMBER OF THE FILE, AND ADJUST THE CLUSTER DATA LENGTH FOR THE LAST CLUSTER OF THE FILE. .%589! ;**GET NEXT CLUSTER .%590! LDA CLUSTER .%591! LDY CLUSTER+1 .%592! JSR GET╞AT┼NTRY .%593! STA CLUSTER .%594! STY CLUSTER+1 .%595! CMP #$FF .%596! BNE COPY╞ILE├LUSTER─ATA .%597! CPY #$0F .%598! BNE COPY╞ILE├LUSTER─ATA .%599! LDA LEN═╠ .%600! STA CBM─ATA╠EN .%601! LDA #$01 .%602! LDX CLUSTER┬LOCK├OUNT .%603! CPX #1 .%604! BEQ + .%605! LDA #$03 .%606! + AND LEN═╠+1 ╘HE FOLLOWING THREE LINES WERE ADDED IN A LAST MINUTE PANIC AFTER REALIZING THAT IF ╞ILE╠ENGTH % ├LUSTER╙IZE == 0, THEN THE LAST CLUSTER OF THE FILE CONTAINS ├LUSTER╙IZE BYTES, NOT ZERO BYTES. .%000! BNE + .%000! LDX LEN═╠ .%000! BEQ COPY╞ILE├LUSTER─ATA .%607! + STA CBM─ATA╠EN+1 .%608! .%609! COPY╞ILE├LUSTER─ATA = * .%610! JSR COMMIE╧UT .%611! RTS .%612! ├OPY THE FILE DATA IN THE ═╙-─╧╙ CLUSTER BUFFER TO THE ├┬═ OUTPUT FILE. .%613! CBM─ATA╠IMIT = $66 .%614! .%615! COMMIE╧UT = * ;( CBM─ATA╨TR, CBM─ATA╠EN ) : .├╙=ERR ╔F THE THE LOGICAL FILE NUMBER TO COPY TO IS 0 ("NULL DEVICE"), THEN DON'T BOTHER COPYING ANYTHING. .%616! LDX LFN .%617! BNE + .%618! CLC .%619! RTS ╧THERWISE, PREPARE THE LOGICAL FILE NUMBER FOR OUTPUT. .%620! + JSR KERNEL├HKOUT .%621! BCC COMMIE╧UT═ORE .%622! STA ERRNO .%623! RTS .%624! .%625! COMMIE╧UT═ORE = * ╨ROCESS THE CLUSTER DATA IN CHUNKS OF UP TO 255 BYTES OR THE NUMBER OF DATA BYTES REMAINING IN THE CLUSTER. .%626! LDA #255 .%627! LDX CBM─ATA╠EN+1 .%628! BNE + .%629! LDA CBM─ATA╠EN .%630! + STA CBM─ATA╠IMIT .%631! LDY #0 .%632! - LDA (CBM─ATA╨TR),Y .%633! BIT TRANS═ODE .%634! BPL + ╔F WE HAVE TO TRANSLATE THE CURRENT ┴╙├╔╔ CHARACTER, LOOK UP THE ╨┼╘╙├╔╔ VALUE IN THE TRANSLATION TABLE AND OUTPUT THAT VALUE. ╔F THE TRANSLATION TABLE ENTRY VALUE IS $00, THEN DON'T OUTPUT A CHARACTER (FILTER OUT INVALID CHARACTER CODES). .%635! TAX .%636! LDA TRANS┬UF,X .%637! BEQ COMMIE╬EXT .%638! + JSR KERNEL├HROUT .%639! COMMIE╬EXT = * .%640! INY .%641! CPY CBM─ATA╠IMIT .%642! BNE - .%643! ╔NCREMENT THE CLUSTER BUFFER POINTER AND DECREMENT THE CLUSTER BUFFER CHARACTER COUNT ACCORDING TO THE NUMBER OF BYTES JUST PROCESSED, AND REPEAT THE ABOVE IF MORE FILE DATA REMAINS IN THE CURRENT CLUSTER. .%644! CLC .%645! LDA CBM─ATA╨TR .%646! ADC CBM─ATA╠IMIT .%647! STA CBM─ATA╨TR .%648! BCC + .%649! INC CBM─ATA╨TR+1 .%650! + SEC .%651! LDA CBM─ATA╠EN .%652! SBC CBM─ATA╠IMIT .%653! STA CBM─ATA╠EN .%654! BCS + .%655! DEC CBM─ATA╠EN+1 .%656! + LDA CBM─ATA╠EN .%657! ORA CBM─ATA╠EN+1 .%658! BNE COMMIE╧UT═ORE ╔F WE ARE FINISHED WITH THE CLUSTER, THEN CLEAR THE ├┬═ ╦ERNAL OUTPUT CHANNEL. .%659! JSR KERNEL├LRCHN .%660! CLC .%661! RTS .%662! ╘HE FILE COPYING MAIN ROUTINE. ╙ET UP FOR THE STARTING CLUSTER, AND CALL THE CLUSTER COPYING ROUTINE UNTIL END-OF-FILE IS REACHED. ├HECKS FOR A ╬╒╠╠ CLUSTER POINTER IN THE DIRECTORY ENTRY TO HANDLE ZERO-LENGTH FILES. .%663! COPY╞ILE = * ;( START├LUSTER, LEN═╠, .┴=TRANS═ODE, .╪=LFN ) : .├╙=ERR .%664! LDY #$0E .%665! STY $FF00 .%666! STA TRANS═ODE .%667! STX LFN .%668! LDA START├LUSTER .%669! LDY START├LUSTER+1 .%670! STA CLUSTER .%671! STY CLUSTER+1 .%672! JMP + .%673! - JSR COPY╞ILE├LUSTER .%674! BCC + .%675! RTS .%676! + LDA CLUSTER .%677! CMP #$FF .%678! BNE - .%679! LDA CLUSTER+1 .%680! CMP #$0F .%681! BNE - .%682! CLC .%683! RTS .%684! ╘HIS IS THE TRANSLATION TABLE USED TO CONVERT FROM ┴╙├╔╔ TO ╨┼╘╙├╔╔. ┘OU CAN MODIFY IT TO SUIT YOUR NEEDS IF YOU WISH. ╔F YOU CANNOT REASSEMBLE THIS FILE, THEN YOU CAN SIFT THROUGH THE BINARY FILE AND LOCATE THE TABEL AND CHANGE IT THERE. ┴N ENTRY OF $00 MEANS THE CORRESPONDING ┴╙├╔╔ CHARACTER WILL NOT BE TRANSLATED. ┘OU'LL NOTICE THAT ╔ HAVE SET UP TRANSLATIONS FOR THE FOLLOWING ┴╙├╔╔ CONTROL CHARACTERS INTO ╨┼╘╙├╔╔: ┬ACKSPACE, ╘AB, ╠INEFEED (├╥), AND ╞ORMFEED. ╔ ALSO TRANSLATE THE NON-╨┼╘╙├╔╔ CHARACTERS SUCH AS █, ▄, ▐, AND _ ACCORDING TO WHAT THEY PROBABLY WOULD HAVE BEEN IF ├OMMODORE WASN'T SO CONCERNED WITH THE GRAPHICS CHARACTERS. .%685! TRANS┬UF = * .%686! ;0 1 2 3 4 5 6 7 8 9 A B C D E F .%687! .BYTE $00,$00,$00,$00,$00,$00,$00,$00,$14,$09,$0D,$00,$93,$00,$00,$00 ;0 .%688! .BYTE $00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00 ;1 .%689! .BYTE $20,$21,$22,$23,$24,$25,$26,$27,$28,$29,$2A,$2B,$2C,$2D,$2E,$2F ;2 .%690! .BYTE $30,$31,$32,$33,$34,$35,$36,$37,$38,$39,$3A,$3B,$3C,$3D,$3E,$3F ;3 .%691! .BYTE $40,$C1,$C2,$C3,$C4,$C5,$C6,$C7,$C8,$C9,$CA,$CB,$CC,$CD,$CE,$CF ;4 .%692! .BYTE $D0,$D1,$D2,$D3,$D4,$D5,$D6,$D7,$D8,$D9,$DA,$5B,$5C,$5D,$5E,$5F ;5 .%693! .BYTE $C0,$41,$42,$43,$44,$45,$46,$47,$48,$49,$4A,$4B,$4C,$4D,$4E,$4F ;6 .%694! .BYTE $50,$51,$52,$53,$54,$55,$56,$57,$58,$59,$5A,$DB,$DC,$DD,$DE,$DF ;7 .%695! .BYTE $00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00 ;8 .%696! .BYTE $00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00 ;9 .%697! .BYTE $00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00 ;A .%698! .BYTE $00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00 ;B .%699! .BYTE $00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00 ;C .%700! .BYTE $00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00 ;D .%701! .BYTE $00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00 ;E .%702! .BYTE $00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00 ;F .%703! ╘HIS IS WHERE THE TRACK CACHE, ETC. ARE STORED. ╘HIS SECTION REQUIRES 11╦ OF STORAGE SPACE BUT DOES NOT INCREASE THE LENGTH OF THE BINARY PROGRAM FILE SINCE THESE STORAGE AREAS ARE ─┼╞╔╬┼─ RATHER THAN ALLOCATED WITH ".BUF" DIRECTIVES. ╘HE ╒NIX TERMINOLOGY FOR THIS TYPE OF UNINITIALIZED DATA IS "BSS". .%704! ;====BSS STORAGE==== .%705! .%706! BSS = * .%707! TRACKBUF = BSS .%708! CLUSTER┬UF = TRACKBUF+4608 .%709! FATBUF = CLUSTER┬UF+1024 .%710! DIRBUF = FATBUF+1536 .%711! END = DIRBUF+4096 5. ╒╙┼╥-╔╬╘┼╥╞┴├┼ ╨╥╧╟╥┴═ ╘HIS SECTION PRESENTS THE LISTING OF THE USER-INTERFACE ┬┴╙╔├ PROGRAM. ┘OU SHOULD BE AWARE THAT YOU CAN EASILY CHANGE SOME OF THE DEFAULTS TO YOUR OWN PREFERENCES IF YOU WISH. ╘HIS PROGRAM IS NOT LISTED IN THE ".%NNN!" FORMAT THAT THE ASSEMBLER LISTING IS SINCE YOU CAN RECOVER THIS LISTING FROM THE UUENCODED BINARY PROGRAM FILE. ╘HIS PROGRAM SHOULD BE A LITTLE EASIER TO FOLLOW THAN THE ASSEMBLER LISTING SINCE ┬┴╙╔├ IS A SELF-COMMENTING LANGUAGE. :-) 10 REM LITTLE RED READER, BY CRAIG BRUCE, 30-SEP-92, FOR C= HACKING NETMAG 11 : ╘HESE LINES SET UP THE DEFAULT ├┬═-─╧╙ AND ═╙-─╧╙ DEVICE NUMBERS, TAKING CARE TO DISALLOW THEM TO BE THE SAME DEVICE. ┘OU CAN CHANGE THIS TO YOUR OWN DRIVE CONFIGURATION. 20 CD=PEEK(186) : REM ** DEFAULT CBM-DOS DRIVE ** 25 DV=9:DT=0 : REM ** MS-DOS DRIVE, TYPE (0=1571,255=1581) 26 IF DV=CD THEN DV=8:DT=0 : REM ** ALTERNATE MS-DOS DRIVE 27 : 30 PRINT CHR$(147);"INITIALIZING..." : PRINT 40 BANK0 : PK=DEC("8000") 50 IF PEEK(PK+9)=DEC("CB") AND PEEK(PK+10)=131 THEN 60 55 PRINT"LOADING MACHINE LANGUAGE ROUTINES..." : BLOAD"LRR.BIN",U(CD) 60 POKE PK+16,DV : POKE PK+17,DT : SYS PK ╔ "DIM" THE FOLLOWING VARIABLES BEFORE THE ARRAYS TO AVOID THE OVERHEAD OF PUSHING THE ARRAYS AROUND WHEN CREATING NEW SCALAR VARIABLES. 70 DIM T,R,B,I,A$,C,DT$,FL$,IL$,X,X$ 80 DIM DI$(128),CL(128),SZ(128) 90 IF DT=255 THEN DT$="1581" :ELSE DT$="1571" 100 FL$=CHR$(19)+CHR$(17)+CHR$(17)+CHR$(17)+CHR$(17) 110 IL$=FL$:FORI=1TO19:IL$=IL$+CHR$(17):NEXT 120 GOTO 500 130 : 131 REM ** LOAD MS-DOS DIRECTORY ** 140 PRINT"LOADING DIRECTORY..." : PRINT 150 SYS PK : SYS PK+3 160 DL=0 ╘HE "RREG" INSTRUCTION RETURNS THE RETURN VALUES OF THE .┴, .╪, .┘, AND .╙ REGISTERS FROM THE LAST "SYS" CALL. ╔ CHECK THE 1-BIT OF THE .╙ REGISTER (THE ├ARRY FLAG) FOR ERROR RETURNS. 170 RREG BL,DC,BH,S : E=PEEK(PK+15) 180 IF (S AND 1) THEN GOSUB 380 : RETURN 190 PRINT"SCANNING DIRECTORY..." : PRINT 200 DB=BL+256*BH 210 IF DC=0 THEN 360 220 FOR DP=DB TO DB+32*(DC-1) STEP 32 230 IF PEEK(DP)=0 OR PEEK(DP)=229 THEN 350 240 IF PEEK(DP+12) AND 24 THEN 350 250 DL=DL+1 ╘HIS NEXT LINE IS WHERE ╔ SET THE DEFAULT SELECTION STATUS, TRANSLATION TYPE, AND ├┬═ FILE TYPE FOR THE ═╙-─╧╙ FILES. ┘OU CAN CHANGE THESE DEFAULTS SIMPLY BY OVERTYPING THE STRING IN ( ▄ ▄▄▄ ▄▄▄ ) THE "╓" LOCATIONS. ╓ ╓╓╓ ╓╓╓ 260 D$=RIGHT$(" "+STR$(DL),3)+" ASC SEQ " : REM ** DEFAULT SEL/TR/FT ** 270 A$="" : FORI=0TO10 : A$=A$+CHR$(PEEK(DP+I)) : NEXT 280 A$=LEFT$(A$,8)+" "+RIGHT$(A$,3) 290 PRINT DL; A$ 300 D$=D$+A$+" " 310 CL(DL)=PEEK(DP+26)+256*PEEK(DP+27) 320 SZ=PEEK(DP+28)+256*PEEK(DP+29)+65536*PEEK(DP+30) 330 DI$(DL)=D$+RIGHT$(" "+STR$(SZ),6) 340 SZ(DL)=SZ 350 NEXT DP 360 RETURN 370 : 371 REM ** REPORT MS-DOS DISK ERROR ** 380 PRINT CHR$(18);"MS-DOS DISK ERROR #";MID$(STR$(E),2); 390 PRINT " ($";MID$(HEX$(E),3);"), PRESS KEY.";CHR$(146) 400 GETKEY A$ : RETURN 410 : 411 REM ** SCREEN HEADING ** 420 PRINTCHR$(147);"MS-DEV=";MID$(STR$(DV),2);" MS-TYPE=";DT$; 430 PRINT" CBM-DEV=";MID$(STR$(CD),2):PRINT 440 RETURN 450 : 451 REM ** SCREEN FOOTING ** 460 PRINT IL$;"D=DIRECTORY M=MS-DEV F=CBM-DEV Q=QUIT" 470 PRINT"T=TOGGLE-COLUMN, C=COPY-FILES, +/- PAGE"; 480 RETURN 490 : 491 REM ** MAIN ROUTINE ** 500 T=1 : C=0 510 R=0 520 GOSUB 420 530 PRINT "NUM S TRN TYP FILENAME EXT LENGTH" 540 PRINT "--- - --- --- -------- --- ------" 550 GOSUB 460 560 B=T+17 : IF B>DL THEN B=DL 570 PRINT FL$;: IF T>DL THEN 590 580 FOR I=T TO B : PRINT DI$(I) : NEXT 590 IF DL=0 THEN PRINT CHR$(18);"<NO FILES>";CHR$(146) 600 IF DL=0 THEN 660 610 PRINT LEFT$(IL$,R+5);CHR$(18); 620 ON C+1 GOTO 630,640,650 630 PRINT SPC(4);MID$(DI$(T+R),5,3) : GOTO 660 640 PRINT SPC(7);MID$(DI$(T+R),8,5) : GOTO 660 650 PRINT SPC(12);MID$(DI$(T+R),13,5) : GOTO 660 660 GETKEY A$ ╧H SHI^╚OOT. ╔ SCREWED UP THE FOLLOWING LINE IN THE STRING AFTER THE "+CHR$(13)+" PART. ┘OU'LL NOTICE THAT ╔ HAVE AVOIDED PUTTING CURSOR CONTROL CHARACTERS INTO THE STRINGS EVERYWHERE ELSE, BUT ╔ FORGOT TO DO THAT HERE. ╘HE "█STUFF▌" SHOULD BE ├URSOR╒P, ├URSOR─OWN, ├URSOR╠EFT, ├URSOR╥IGHT, ├URSOR╚OME, AND ├URSOR├╠╥ CONTROL CHARACTERS, RESPECTIVELY. ╘HESE CHARACTERS GIVE THE INDEX FOR THE "ON" STATEMENT BELOW. 670 I=INSTR("DMFTC+-Q "+CHR$(13)+"█STUFF▌",A$) 680 PRINT LEFT$(IL$,R+5);DI$(T+R) 690 IF I=0 THEN 600 700 ONIGOTO760,1050,1110,950,1150,1000,1020,730,860,860,770,790,810,830,850,500 710 STOP 720 : 721 REM ** VARIOUS MENU OPTIONS ** 730 PRINT CHR$(147);"HAVE AN AWESOME DAY." 740 END 760 GOSUB 420 : GOSUB 140 : GOTO 500 770 R=R-1 : IF R<0 THEN R=B-T 780 GOTO 600 790 R=R+1 : IF T+R>B THEN R=0 800 GOTO 600 810 C=C-1 : IF C<0 THEN C=2 820 GOTO 600 830 C=C+1 : IF C>2 THEN C=0 840 GOTO 600 850 R=0 : C=0 : GOTO 600 860 IF DL=0 THEN 600 870 X=T+R : ON C+1 GOSUB 890,910,930 880 PRINT LEFT$(IL$,R+5);DI$(X) : GOTO 600 890 IF MID$(DI$(X),6,1)=" " THEN X$="*" :ELSE X$=" " 900 MID$(DI$(X),6,1)=X$ : RETURN 910 IF MID$(DI$(X),9,1)="A" THEN X$="BIN" :ELSE X$="ASC" 920 MID$(DI$(X),9,3)=X$ : RETURN 930 IF MID$(DI$(X),14,1)="S" THEN X$="PRG" :ELSE X$="SEQ" 940 MID$(DI$(X),14,3)=X$ : RETURN 950 IF DL=0 THEN 600 960 FOR X=1 TO DL 970 ON C+1 GOSUB 890,910,930 980 NEXT X 990 GOTO 520 1000 IF B=DL THEN T=1 : GOTO 510 1010 T=T+18 : GOTO 510 1020 IF T=1 THEN T=DL-(DL-INT(DL/18)*18)+1 : GOTO 510 1030 T=T-18 : IF T<1 THEN T=1 1040 GOTO 510 1050 PRINT IL$;CHR$(27);"@"; 1060 INPUT"MS-DOS DEVICE NUMBER (8-30)";DV 1061 IF CD=DV THEN PRINT"MS-DOS AND CBM-DOS DEVICES MUST BE DIFFERENT!":GOTO1060 1070 INPUT"MS-DOS DEVICE TYPE (71/81)";X 1080 IF X=8 OR X=81 OR X=1581 THEN DT=255:DT$="1581" :ELSE DT=0:DT$="1571" 1090 POKE PK+16,DV : POKE PK+17,DT : SYS PK 1100 GOTO 520 1110 PRINT IL$;CHR$(27);"@"; 1120 INPUT "CBM-DOS DEVICE NUMBER (0-30)";CD 1130 IF CD=DV THEN PRINT"MS-DOS AND CBM-DOS DEVICES MUST BE DIFFERENT!":GOTO1120 1140 GOTO 520 1141 : 1142 REM ** COPY FILES ** 1150 PRINT CHR$(147);"COPY FILES":PRINT:PRINT 1160 IF DL=0 THEN FC=0 : GOTO 1190 1170 FC=0 : FOR F=1 TO DL : IF MID$(DI$(F),6,1)="*" THEN GOSUB 1200 1180 NEXT F 1190 PRINT : PRINT"FILES COPIED =";FC;" - PRESS KEY" 1191 GETKEY A$ : GOTO 520 1200 FC=FC+1 1210 X$=MID$(DI$(F),19,8)+"."+MID$(DI$(F),29,3) 1220 CF$="":FORI=1TOLEN(X$):IF MID$(X$,I,1)<>" " THEN CF$=CF$+MID$(X$,I,1) 1230 NEXT 1231 IF RIGHT$(CF$,1)="." THEN CF$=LEFT$(CF$,LEN(CF$)-1) 1232 CF$=CF$+","+MID$(DI$(F),14,1) 1240 PRINT STR$(FC);". ";CHR$(34);CF$;CHR$(34);TAB(20);SZ(F)"BYTES"; 1245 PRINT TAB(35);MID$(DI$(F),9,3) 1250 CL=CL(F) : LB=SZ(F) - INT(SZ(F)/65536)*65536 ╔ HAD TO USE A ─╧╨┼╬ STATEMENT HERE FOR DISK FILES BECAUSE THE REGULAR ╧╨┼╬ STATMENT DOES NOT REDIRECT THE ─╙ AND ─╙$ PSEUDO-VARIABLES. ┘OU'LL NOTICE THAT THE NON-DISK ╧╨┼╬ STATMENT BELOW HAS A SECONDARY ADDRESS OF 7. ╘HIS IS TO PUT THE PRINTER INTO LOWERCASE MODE IF YOU ARE OUTPUTTING DIRECTLY TO IT. ┘OU CAN REPLACE THIS WITH A 5 (OR WHATEVER) IF YOU HAVE A SPECIAL INTERFACE TO AN ╔┬═-COMPATIBLE PRINTER AND YOU WANT TO PRINT DIRECTLY IN ┴╙├╔╔. ╔N THIS CASE, YOU WOULD SELECT THE "┬╔╬" TRANSLATION MODE FOR THE FILE YOU ARE ROUTING DIRECTLY TO THE PRINTER. 1260 IF CD>=8 THEN DOPEN#1,(CF$+",W"),U(CD) :ELSE IF CD<>0 THEN OPEN 1,CD,7 1265 IF CD<8 THEN 1288 1270 IF DS<>63 THEN 1288 1275 X$="Y" : PRINT "FILE EXISTS; OVERWRITE (Y/N)"; 1280 CLOSE 1 : INPUT X$ : IF X$="N" THEN FC=FC-1 : RETURN 1285 SCRATCH(CF$),U(CD) 1286 DOPEN#1,(CF$+",W"),U(CD) 1288 IF CD<8 THEN 1320 1300 IF DS<20 THEN 1320 1310 PRINT CHR$(18)+"CBM DISK ERROR: "+DS$ : FC=FC-1 : CLOSE1 : RETURN 1320 POKE PK+19,CL/256 : POKE PK+18,CL-PEEK(PK+19)*256 1330 POKE PK+21,LB/256 : POKE PK+20,LB-PEEK(PK+21)*256 1340 TR=0 : IF MID$(DI$(F),9,1)="A" THEN TR=255 1346 X=1 : IF CD=0 THEN X=0 1350 SYS PK+6,TR,X 1355 RREG X,X,X,S : E=PEEK(PK+15) 1356 IF (S AND 1) THEN GOSUB 380 : FC=FC-1 1360 IF CD<>0 AND CD<8 THEN CLOSE1 1370 IF CD>=8 THEN DCLOSE#1 : IF DS>=20 THEN 1310 1380 RETURN 6. ╒╒┼╬├╧─┼─ ╞╔╠┼╙ ╚ERE ARE THE BINARY EXECUTABLES IN UUENCODED FORM. ╘HE ├╥├32S OF THE TWO FILES ARE AS FOLLOWS: "LRR.128" 1106058594 "LRR.BIN" 460671650 ╘HE "LRR.128" FILE IS THE MAIN ┬┴╙╔├ PROGRAM AND THE "LRR.BIN" FILE CONTAINS THE MACHINE LANUGAGE DISK-ACCESSING ROUTINES. 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[2] ├OMMODORE ┬USINESS ═ACHINES, _├OMMODORE_1571_─ISK_─RIVE_╒SER'S_╟UIDE_, ├┬═, 1985. [3] ╙OME PROGRAM CALLED "MSDOS-TO-128" INCLUDED WITH "CS-DOS" BY ═. ╟-SOMETHING. ╧RIGINALLY PUBLISHED IN ├╧═╨╒╘┼!'S ╟AZZETTE, ╔ THINK. [4] ├OMMODORE ┬USINESS ═ACHINES, _├OMMODORE_128_╨ROGRAMMER'S_╥EFERENCE_╟UIDE_, ┬ANTAM ┬OOKS, 1986. [5] _╘HE_╘RANSACTOR_, ╓OLUME 4, ╔SSUE 05 ("╘HE ╥EFERENCE ╔SSUE"), ═AY 1983. ============================================================================= ╬EXT ╔SSUE: ╠EARNING ═ACHINE ╠ANGUAGE - ╨ART 5 ╘HE ╙╨┴├┼ ╔╬╓┴╙╔╧╬ IS CONTINUED WITH THE DESIGN AND IMPLEMENTATION OF THE PLAYER AND ALIEN ANIMATION ALONG WITH A LOOK AT DEVICE SCANNING FOR THE 1351 MOUSE, JOYSTICK AND KEYBOARD. ╘HE 1351 ═OUSE ─EMYSTIFIED ╞INALLY! - ┴FTER 2 DELAYS, THIS ARTICLE WILL EXPLAIN HOW THE 1351 MOUSE WORKS AS WELL AS PROVIDE A EASY TO USE INTERFACE IN MACHINE LANGUAGE FOR BOTH BASIC AND MACHINE LANGUAGE PROGRAMMERS. ┴N EXAMPLE PROGRAM WILL BE GIVEN TO ILLUSTRATE BOTH THE 1351 MOUSE AND THE MULTI-TASKING SYSTEM. ═ULTI-TASKING ON THE ├=128 ┴ RUDIMENTARY MULTI-TASKING SYSTEM WILL BE IMPLEMENTED FOR TASKS TO RUN CON-CURRENTLY WITH EACH OTHER. ╫HILE INTENDED FOR MACHINE LANGUAGE PROGRAMMERS SOME DISCUSSION OF HOW TO USE THIS WITHIN BASIC WILL BE GIVEN SO THAT MORE THAN ONE BASIC / ML PROGRAM CAN BE RUN AT A TIME. ┴N EXAMPLE PROGRAM WILL BE GIVEN TO ILLUSTRATE BOTH THE 1351 MOUSE AND THE MULTI-TASKING SYSTEM. ╙TRETCHING SPRITES ┘OU MIGHT HAVE HEARD THAT IT IS POSSIBLE TO EXPAND SPRITES TO MORE THAN TWICE THEIR ORIGINAL SIZE. ┬UT THERE IS NO NEED TO EXPAND ALL OF THEM EQUALLY. ╘HIS ARTICLE WILL EXAMINE ON HOW TO EXPAND THEM 2,3 OR MORE MULTIPLES OF THEIR ORIGINAL SIZE. ╠╔╘╘╠┼ ╥┼─ ╫╥╔╘┼╥: ═╙-─╧╙ FILE WRITER FOR THE 128 AND 1571/81 DRIVES. ╘HIS ARTICLE WILL EXTEND THE ╠ITTLE ╥ED ╥EADER PROGRAM TO BE ABLE TO WRITE ├OMMODORE-─╧╙ FILES TO AN ═╙-─╧╙ DISK. =============================================================================