|
Volume Number: | 4 | |
Issue Number: | 2 | |
Column Tag: | Forth Forum |
A SCSI Driver in Forth
By Jörg Langowski, MacTutor Editorial Board, Grenoble, France
“An experimental SCSI driver in Mach2”
This column almost didn’t make it in time. Believe it or not, but while testing the SCSI driver of this article, my Quantum Q280 gave up. No, read on, it wasn’t the software. (How could it be MY software, anyway?) The interface board let go, and there was my most recent version of the driver, on the disk, inaccessible, me dummy having made no backup for the last 2 days. Left with ‘only’ a 20 MByte Seagate drive, I was going through a non-trivial exercise on how to debug a SCSI driver on the same disk which is used for developing it. You cannot imagine the strange things that can happen when booting from a disk with a partially functioning driver; it sometimes forces you into doing absolute no-nos such as booting from a floppy and attaching the SCSI connector afterwards so you can re-install the driver without getting la bombe immediately. At least, the development cycle is slowed down appreciably, since every other time you’ll have to boot from a floppy.
Anyway, here it is. The listing contains the Forth source of a SCSI driver which is more or less a translation of Apple’s assembly source into Mach2. It is quite long, and I’m not going through all of it in detail, having explained the function of most of the routines in my last column. One added feature is error retry; if a SCSI error happens, the offending command is repeated up to ten times.
The driver takes 50% more space than the assembly version and is about half as fast. So, you may ask, why go through all this trouble? You might have noticed the title ‘An experimental SCSI driver’. The code is meant for you to experiment with, add features - such as better error recognition and correction, multi- volume support, anything you may imagine. Or translate part of the routines into C or assembler. I just felt it was necessary to have a functioning example of a SCSI driver in some ‘higher-level’ language to make changes easier.
From the Forth point of view, I added a number of compiling words and glue routines that may be helpful for you in developing other things.
You already know the words :XDEF, ;XDEF, and XLEN from the Hypercard article. For easier programming of drivers and desk accessories, I now added :DA, ;DA, and DALEN which define the header of a driver, fill in the header after its definition is complete, and return the total length of the driver.
Since the SCSI driver code is jumped to at the beginning, it looks like other definition procedures from the outside, and its definition is therefore embedded between :XDEF and ;XDEF. In its interior, the SCSI driver contains a real DRVR, with is bracketed between :DA and ;DA. You recognize the glue code for the Open, Close, Control, Status and Prime routines at the end of the listing; the glue routines have been simplified by introducing macros for register save/restore and eventual jumps to the JIODone routine.
The Prime routine
Prime is the only one that has to be explained in more detail here since it has been modified with respect to the description given in the last issue. I added an error retry loop, and transfer of the SCSI data in variable size chunks. The code as printed takes 127 sectors on each read or write, that is, any amount of data larger than that will be transferred using several calls to the SCSICommon routine. This has been worked out empirically; larger transfer sizes would not work on the ST225N (which would result in files > 64K not being copied on a Finder copy). Your disk drive may allow larger sizes or need smaller ones; check this out if you like. You might also want to change the Read/Write Extended to a simple Read/Write command, or use a multi-transfer SCSI instruction block. The driver is certainly not generic and might need such adjustments to work on your disk.
SCSI Installation
The installation part has been changed slightly, and you’ll have to replace parts of the installer code given in the last column. First, I changed the device and partition maps such that the driver starts at block 4 and the Macintosh volume partition at block 16. This is where the Apple Hard Disk installation program seems to expect it, therefore you can easily replace this driver with the Apple driver in case of problems, without haveing to reformat the disk. Furthermore, I added a small routine that will install the driver code in the system heap and call it so that it gets installed in the unit table; this is an easy way of testing the driver without writing it to disk. You can even install the same disk that you are using to write the program, in which case you will be left with two drive icons on the desktop, referring to the same disk. For testing, this is OK, only don’t work too much in such an awkward configuration.
I hope this series of two articles has given you some ideas on how to write your own SCSI driver for your particular device. If someone comes up with a good examples for controlling a tape streamer - we’re always open for contributions, as you know.
Feedback Dept.
Someone read my complaints about the missing editor in Mach2; a letter with a disk arrived here recently:
“Dear Mr. Langowski,
I’m afraid I’m not a fan of Forth [Oh JL]. I like the idea of a stack-based language but there’s an impenetrable jargon barrier Besides, I just don’t like typing shifted characters, like #, !, % and so on. So I stay home with Pascal and Assembler.
On the other hand, I always at least glance at your column in MacTutor (as well as every other article that isn’t Mac II- specific). In the October issue, you say, ‘It is a shame that a powerful development system like Mach2 still lacks a reasonable integrated editor. At least multiple windows should be possible My standard development system is Mach2.13 with its editor and Mockwrite, plus Edit under Switcher if required.’ I’m stunned. The idea of using Mockwrite in a development system! The Mach2 editor must be really bad [ It’s not bad for what it does, i.e., has no major bugs; but I admit its features are limited - JL].
I had an editor problem myself, working with TML Pascal. TML won’t really run under the Switcher; it demands too much memory. So if I make a syntax error, I have to transfer to the editor, which means quitting the compiler and launching the editor, fix the error, then quit the editor and re-launch the compiler. Then I can re-compile. Something of a pain, particularly since error-free code is somewhat rare, at least when I’m the coder! [This sounds familiar. JL] My solution: Afterthought, a desk accessory programming editor. Now I fix bugs without leaving the compiler.
My problem is solved, and yours may be as well. I’m sending you a copy of Afterthought. It will open large files (up to 8 Megabytes), two at a time. It has most of the features of MDS Edit - the most significant exception is Replace All. And it’s reasonably fast. At the very least, it is better than Mockwrite!
Sincerely,
Clifford Story, Jimmy Mac Software, P.O.Box 957, Murfreesboro, Tennessee 37133.”
Thank you, Clifford, for developing a product that - I guess - many of our readers have been waiting for.
The disk contained the Afterthought desk accessory, its manual, some update notes and examples, a demo version, and a demo version of Idealiner, an idea processor written by the same author. The prices are, by the way, extremely reasonable; $20 for the editor and $40 for the idea processor. To find out more about these products, send mail to the above address, or GEnie mail to CLIFF.
The second editor desk accessory product that I find worth mentioning is JoliWrite, written by Benoît Widemann from Paris, a small (32K limit) text editor that is extremely useful for working with bulletin board services. Often, when you prepare a text off line for a BBS message, you wish to be able to enter the text free-format and then format into lines of so and so many characters, with paragraph indentation and justification if desired. Also, over here it is often necessary to convert accentuated characters from Macintosh into ASCII representation and back, and in general you might wish to be able to remove/add line feeds, clip off numbers from line starts, etc. JoliWrite does all that, and in addition is one of the few products that supports Undo on all operations. By the time you read this, an English translation of JoliWrite (shareware, 120F/US$20) will hopefully be available on the Macintosh section of GEnie.
Listing 1: An experimental SCSI driver ( © 1987 J. Langowski / MacTutor ) only forth definitions also mac also assembler CODE SCALE MOVE.L (A6)+,D0 BMI.S @1 MOVE.L (A6),D1 ASL.L D0,D1 MOVE.L D1,(A6) RTS @1 MOVE.L (A6),D1 NEG.L D0 ASR.L D0,D1 MOVE.L D1,(A6) RTS END-CODE : 4ASCII 0 4 0 DO 8 SCALE 0 WORD 1+ C@ + LOOP ; ( *** compiler support words for external definitions *** ) : :xdef create -4 allot $4EFA w, ( JMP ) 0 w, ( entry point to be filled later ) 0 , ( length of routine to be filled later ) here 6 - 76543 ; : ;xdef { branch marker entry | -- } marker 76543 <> abort” xdef mismatch” entry branch - branch w! here branch - 2+ branch 2+ ! ; : xlen 4 + @ ; ( get length word of external definition ) ( *** driver header block *** ) 0 CONSTANT drvrFlags 2 CONSTANT drvrdelay 4 CONSTANT drvrEMask 6 CONSTANT drvrMenu 8 CONSTANT drvrOpen 10 CONSTANT drvrPrime 12 CONSTANT drvrCtl 14 CONSTANT drvrStatus 16 CONSTANT drvrClose 18 CONSTANT drvrname 50 CONSTANT DAlength ( *** compiler support words for DA and driver definitions *** ) : :DA create -4 allot here 87654 ( start of DA block, and marker ) 54 allot ( length of block ) ; : ;DA { DAstart marker Ropen Rprime Rctl Rstatus Rclose Rflags Rdelay Remask Rmenu Rname | -- } marker 87654 <> abort” DA definition mismatch” Ropen DAStart - DAStart drvrOpen + w! Rprime DAStart - DAStart drvrPrime + w! Rctl DAStart - DAStart drvrCtl + w! Rstatus DAStart - DAStart drvrStatus + w! Rclose DAStart - DAStart drvrClose + w! Rflags DAStart drvrFlags + w! Rdelay DAStart drvrDelay + w! Remask DAStart drvrEmask + w! RMenu DAStart drvrMenu + w! Rname count dup DAStart drvrName + c! DAStart drvrName + 1+ swap dup 31 > if drop 31 then cmove here DAstart - DAStart DAlength + ! ; : DAlen DAlength + @ ; ( get length word of external definition ) \ ------------------------------------------------------ \ some macros needed in the driver \ ------------------------------------------------------ CODE xchg ( exchange word halves on top of stack ) move.l (a6)+,d1 swap.w d1 move.l d1,-(a6) rts END-CODE MACH CODE min MOVE.L (A6)+,D0 CMP.L (A6),D0 BGE.S @1 MOVE.L D0,(A6) @1 RTS END-CODE MACH CODE shl ( data #bits ) MOVE.L (A6)+,D0 MOVE.L (A6),D1 LSL.L D0,D1 MOVE.L D1,(A6) RTS END-CODEMACH CODE shr ( data #bits ) MOVE.L (A6)+,D0 MOVE.L (A6),D1 LSR.L D0,D1 MOVE.L D1,(A6) RTS END-CODEMACH CODE w* MOVE.L (A6)+,D1 MOVE.L (A6)+,D0 MULS.W D1,D0 MOVE.L D0,-(A6) RTS END-CODE MACH \ ------------------------------------------------------ \ **** DA glue macros \ ------------------------------------------------------ $8FC CONSTANT JioDone CODE DA.prelude LINK A6,#-512 ( 512 bytes of local Forth stack ) MOVEM.L A0-A1,-(A7) ( save registers ) MOVE.L A6,A3 ( setup local loop return stack ) SUBA.L #256,A3 ( in the low 256 local stack bytes ) MOVE.L A0,-(A6) ( parameter block ) MOVE.L A1,-(A6)( device control entry ) RTS \ just to indicate the MACHro stops here END-CODE MACH CODE DA.epilogue MOVE.L (A6)+,D0( return code ) MOVEM.L (A7)+,A0-A1 ( restore registers ) UNLK A6 RTS END-CODE MACH CODE DA.JIODone MOVE.L (A6)+,D0( return code ) MOVEM.L (A7)+,A0-A1 ( restore registers ) UNLK A6 move.l JIODone,A0 movem.l d4-d7/a4-a6,-(a7) jsr (a0) movem.l(a7)+,d4-d7/a4-a6 RTS END-CODE MACH .trap _newptr,sys,clr$A71E \ fields of device control entry 4 CONSTANT dCtlFlags 6 CONSTANT dCtlQHdr 16 CONSTANT dCtlPosition 20 CONSTANT dCtlStorage 24 CONSTANT dCtlRefNum 26 CONSTANT dCtlCurTicks 30 CONSTANT dCtlWindow 34 CONSTANT dCtlDelay 36 CONSTANT dCtlEMask 38 CONSTANT dCtlMenu \ parameter block constants 0 CONSTANT qLink\ ptr to next queue entry[long word] 4 CONSTANT qType\ queue type [word] 6 CONSTANT ioTrap \ routine trap [word] 7 CONSTANT ioTrap+1 \ read or write command 8 CONSTANT ioCmdAddr \ routine address [long word] 12 CONSTANT ioCompletion\ addr of completion routine 16 CONSTANT ioResult \ result code returned here 18 CONSTANT ioNamePtr \ pointer to file name string 22 CONSTANT ioVRefNum \ volume reference number 26 CONSTANT csCode ( type of control call ) 28 CONSTANT csParam( control call parameters ) \ MFS I/O Parameter Block 24 CONSTANT ioRefNum 26 CONSTANT ioVersNum 27 CONSTANT ioPermssn 28 CONSTANT ioMisc 32 CONSTANT ioBuffer 36 CONSTANT ioReqCount 40 CONSTANT ioActCount 44 CONSTANT ioPosMode 46 CONSTANT ioPosOffset 50 CONSTANT IOParamBlkSize 4ascii SDRV constant “sdrv 4ascii TFS1 constant “tfs1 \ Equates \ My excuses for the format. This has been taken almost \ ‘as is’ from Apple’s SCSI driver example. - jl - EQUverChar$34 \ version ‘4’ EQUSCSIZE 10 \ size of SCSI extended command \ Equates for our storage (pointed to by DCtlStorage) EQUOffset 0 \ [long] offset of starting sector EQUMyDQEl Offset+4 \ [20 bytes] drive queue element (with flags) for this drive EQUMyDrvNum MyDQEl+20 \ [word] drive num (determined by scanning drive queue) EQUNextAddr MyDrvNum+2 \ [long] ptr to current block buffer EQUTickleFlag NextAddr+4 \ [byte] Do we need to remind the system about this drive? EQUBlindOKTickleFlag+1 \ [byte] Can we use blind reads? \ I left this in to keep the format the same. \ We don’t need it since our driver does not read blind. EQUSCmd BlindOK+1 \ [10 bytes] SCSI extended cmd Block /JL EQUStatWord SCmd+10 \ [word] status and message bytes... EQUMsgWordStatWord+2 \ [word] ... returned by SCSIComplete EQUOurIDMsgWord+2 \ [word] our SCSI ID EQUSCSIPseudo OurID+2 \ [30 bytes] SCSI pseudo-code program \ - three instructions long EQUSCSIPar1 SCSIPseudo+2 \ first SCSI code paramr (long) EQUSCSIPar2 SCSIPar1+4 \ 2nd SCSI code parameter (long) EQUDiskVarLth SCSIPseudo+(SCSIZE*3) \ length of our locals . . . EQU DQDrvSize 12 EQU realSizeMyDQEl+DQDrvSize+4 \ equates for CSParam offsets for our special control call EQUDSCCmd CSParam \ Ptr to SCSI command block EQUDSCPseudoDSCCmd+4 \ Ptr to SCSI pseudocode (if any bytes to xfer) EQUDSCBufferDSCPseudo+4 \ Ptr to buffer for transfer (if any) EQUDSCSizeDSCBuffer+4\ Size of transfer, signed (+ if read, - if write) EQUDSCTicks DSCSize+4\ Tick count we’re willing to wait for completion EQUDSCCmdSize DSCTicks+4 \ (word) Size of command block we’re sending (usually 6) EQU KillCode 1 EQUVerifyCode 5 EQUFormatCode 6 EQUEjectCode7 EQUIconCode 21 EQU AccRun65 EQUSCSICode 77 \ our own special code (defined above) EQUControlErr -1 EQUStatusErr-1 EQUParamErr -50 EQUnsDrvErr -56 EQUnsVErr -35 EQUioErr-36 EQUdNeedTime$DFFF \ to clear bit 5 of high byte in drvrFlags EQUDiskInsertEvt 7 EQU SysEvtMask $144 EQU UTableBase $11C EQU DrvQHdr $308 EQU QHead $2 EQUDQDrive6 EQUDQRefNum 8 EQUDQFSid 10 EQUPDSig0 EQUPDSigWord$5453 EQUPDFSID 8 EQUPDLen12 \ ______________________________________________ \ The code starts here. \ ______________________________________________ :XDEF ScsiDisk \ compiles a jump to the install code at the end \ which will be resolved at the end of the definition. :DADiskDrvr \ this word provides the driver header structure .ALIGN \ Q200 Icon, as given by Quantum \ If you find this ‘snail’ ugly, feel free to change it ... \ J.L. header SCSIIcon DC.L $00000000 DC.L $00000000 DC.L $00000000 DC.L $000FF000 DC.L $003FFC00 DC.L $00FFFF00 DC.L $01FFFF80 DC.L $03F81FC0 DC.L $07E007E0 DC.L $07C003E0 DC.L $0F8001F0 DC.L $0F0000F0 DC.L $1F0000F8 DC.L $1E000078 DC.L $1E000078 DC.L $1E000078 DC.L $1E000078 DC.L $1E000078 DC.L $1E000078 DC.L $1F0000F8 DC.L $0F0000F0 DC.L $0F8001F0 DC.L $07C003E0 DC.L $07E007E0 DC.L $03F80000 DC.L $01FFFFF0 DC.L $00FFFFF8 DC.L $003FFFF8 DC.L $000FFFF8 DC.L $00000000 DC.L $00000000 DC.L $00000000 DC.L $00000000 DC.L $00000000 DC.L $000FF000 DC.L $003FFC00 DC.L $00FFFF00 DC.L $01FFFF80 DC.L $03FFFFC0 DC.L $07FFFFE0 DC.L $0FFFFFF0 DC.L $0FFFFFF0 DC.L $1FFFFFF8 DC.L $1FFFFFF8 DC.L $3FFFFFFC DC.L $3FFFFFFC DC.L $3FFFFFFC DC.L $3FFFFFFC DC.L $3FFFFFFC DC.L $3FFFFFFC DC.L $3FFFFFFC DC.L $3FFFFFFC DC.L $1FFFFFF8 DC.L $1FFFFFF8 DC.L $0FFFFFF0 DC.L $0FFFFFF0 DC.L $07FFFFF0 DC.L $03FFFFF8 DC.L $01FFFFFC DC.L $00FFFFFC DC.L $003FFFFC DC.L $000FFFFC DC.L $00000000 DC.L $00000000 \ Our “Where:” string DC.B 11 DC.B ‘Q200 (SCSI)’ .ALIGN \ SCSI handler glue routines CODE SCSIReset ( -- result code ) CLR.W -(A7) MOVE.W #0,-(A7) _SCSIDispatch MOVE.W (A7)+,D0 EXT.L D0 MOVE.L D0,-(A6) RTS END-CODE CODE SCSIGet ( -- result code ) CLR.W -(A7) MOVE.W #1,-(A7) _SCSIDispatch MOVE.W (A7)+,D0 EXT.L D0 MOVE.L D0,-(A6) RTS END-CODE CODE SCSISelect ( TargetID -- SCSIErrorResult ) MOVE.L (A6)+,D0 CLR.W -(A7) MOVE.W D0,-(A7) MOVE.W #2,-(A7) _SCSIDispatch MOVE.W (A7)+,D0 EXT.L D0 MOVE.L D0,-(A6) RTS END-CODE CODE SCSICmd ( buffer count -- SCSIErrorResult ) MOVE.L (A6)+,D0 MOVE.L (A6)+,D1 CLR.W -(A7) MOVE.L D1,-(A7) MOVE.W D0,-(A7) MOVE.W #3,-(A7) _SCSIDispatch MOVE.W (A7)+,D0 EXT.L D0 MOVE.L D0,-(A6) RTS END-CODE CODE SCSIComplete ( waitTicks mess stat -- SCSIErrorResult ) CLR.W -(A7) MOVE.L (A6)+,-(A7) MOVE.L (A6)+,-(A7) MOVE.L (A6)+,-(A7) MOVE.W #4,-(A7) _SCSIDispatch MOVE.W (A7)+,D0 EXT.L D0 MOVE.L D0,-(A6) RTS END-CODE 1 CONSTANT SCInc 2 CONSTANT SCnoInc 3 CONSTANT SCAdd 4 CONSTANT SCMove 5 CONSTANT SCLoop6 CONSTANT SCNop 7 CONSTANT SCStop8 CONSTANT SCComp \ ---------------------------------------------------- \ main driver routines start here \ ---------------------------------------------------- : SCSICommon \ written to emulate the SCSICommon \ routine in Apple’s example \ as closely as possible. { pseudo cmdblock ourVars ticks bytes cmdsize | writing mess stat -- result } SCSIGet 0= IF ourVars ourID + w@ SCSISelect 0= IF cmdBlock cmdSize SCSICmd 0= bytes AND IF pseudo bytes 0< \ bytes <0 if writing IF (call) SCSIWrite drop ELSE (call) SCSIRead drop THEN \ Note: Your system may be able to support blind transfers. \ Here is the place to experiment with such things -- THEN ticks ^ mess ^ stat SCSIComplete 0= IF stat $FF AND IF ioErr ( there was an SCSI error ) ELSE 0 ( successful completion ) THEN ELSE ( complete unsuccessful ) ioErr THEN ELSE ( select unsuccessful ) ioErr THEN ELSE ( get unsuccessful ) ioErr THEN ; : DiskClose { parblk dce | -- result } 0 ( result code = OK ) ; : diskControl { parblk dce | ourVars -- result } dce DCtlStorage + @ -> ourVars parblk csCode + w@ CASE killCode OF0 ENDOF verifyCode OF 0 ENDOF formatCode OF 0 ENDOF ejectCodeOF ourVars MyDrvNum + w@ \ check drive # in request parblk IOVRefNum + w@ = \ the same? IF SysEvtMask w@ IF ( we’re not at boot time ) DiskInsertEvt MyDrvNum ourVars + w@ (call) PostEvent drop ELSE ( boot time ) 1 ourVars tickleFlag + c! ( drive will be remembered after boot ) THEN controlErr ELSE nsDrvErr THEN ENDOF iconCode OF [‘] SCSIIcon parblk csParam + ! 0 ENDOF accRun OF ourVars tickleFlag + c@ ourVars offset + @ 0= not ( we have a good partition ) AND IF DiskInsertEvt MyDrvNum ourVars + w@ (call) PostEvent drop THEN 0 dce DCtlDelay + w! dce DCtlFlags + dup w@ dNeedTime AND swap w! ( clear flag ) 0 ourVars tickleFlag + c! 0 ENDOF scsiCode OF parblk dup DSCPseudo + @ dup DSCCmd + @ ourVars dup DSCTicks + @ dup DSCSize + @ DSCCmdSize + w@ SCSICommon ENDOF ( otherwise ) controlErr ENDCASE ; : DiskStatus { parblk dce | -- result } statusErr ; CODE GetSysPtr move.l (a6)+,d0 _newptr,sys,clr move.l a0,-(a6) rts END-CODE CODE AddDrv ( dqe refnum drv# | -- ) move.l (a6)+,d0 move.l (a6)+,d1 swap.w d0 move.w d1,d0 move.l (a6)+,a0 _AddDrive rts END-CODE : DiskOpen { parblk dce | ourVars thisQElem driveNum dqe SCSIprog -- result } DiskVarLth GetSysPtr dup \ get memory for local variables -> ourVars dce DCtlStorage + ! \ and store pointer to it 100 5 DO \ find unused drive # DrvQHdr QHead + @ -> thisQElem \ scan queue BEGIN thisQElem 0= IF i leave THEN \ end of queue? we have a good number thisQElem DQDrive + w@ i <> WHILE \ keep scanning as long as # is not in use thisQElem ( QLink + ) @ -> thisQElem REPEAT LOOP -> driveNum driveNum ourVars myDrvNum + w! \ remember drive # in local vars \ ( following text taken from Apple’s generic driver ) \ Add a drive to the drive queue. First, some fun facts: \ The drive queue element starts four bytes before the DQEPtr! \ These four bytes contain “hardware-locked”, “ejectable”, and \ “disk-in-place” info. \ \ Not As Interesting But Still True: HFS supports volumes \ >32MBytes, but since the dqDrvSize field in the DQE is only \ a word, the Software Gurus had to resort to bizarre sorcery: \ If the qType field (formerly unused in DQE’s) is 1, the word \ following the dqDriveSize field is assumed to be the high-order \ word of a LongInt block count! (dqDriveSize is still the low- \ order word). It works even if the size doesn’t require both \ words, so we always do it this way. \ \ See: Tech Note #36. ourVars MyDQEl + 8 over w! \ set non-ejectable and clear the rest 2+ 0 over w! 2+ -> dqe \ this is the real start of the DQElem 1 dqe qType + w!\ large vol queue type 0 dqe dqDrvSize + ! \ no size yet 0 dqe dQFSID + w! \ normal file system dqe dce DCtlRefNum + w@ driveNum AddDrv \ add drive to queue \ now set up SCSI pseudo program in driver’s local vars ourVars SCSIPseudo + -> SCSIprog scnoinc SCSIprog w! scstop SCSIprog scsize + w! 0 \ result code = good ; : DiskPrime { parblk dce | ourVars sectors bytes start size r/w sect transferred error -- result } dce dCtlStorage + @ -> ourVars \ setup local var pointer 1 ourVars TickleFlag + c! \ convert byte count into number of sectors parblk IOReqCount + @ 9 shr $1FFFFF AND -> sectors \ convert starting position into sector number dce dCtlPosition + @ 9 shr $1FFFFF AND -> start ourVars realSize + @ xchg -> size \ get drive size start sectors + size 1+ < IF ( valid request ) 0 -> transferred ourVars ( offset + ) @ +> start \ offset by start of partition parBlk IOTrap+1 + c@ 3 = ( is this a write command? ) IF -1 -> r/w $2A00 ( SCSI extended write ) ELSE 1 -> r/w $2800 ( SCSI extended read ) THEN ourVars SCmd + w! \ put the command away BEGIN ( transfer loop ) \ If you have problems getting the SCSI transfer to work \ with your particular disk, try changing the number of \ sectors transferred on each call ( 127 here ) \ or change the read/write extended to a normal read/write. \ Note that in that case you’ll have to change the command \ block setup as well. 127 sectors min -> sect transferred +> start parblk IOBuffer + @ transferred 9 shl + ourVars SCSIPar1 + ! sect 9 shl dup -> bytes ourVars SCSIPar2 + ! \ set # of bytes start ourVars SCmd + 2+ ! \ set starting position in command block bytes 2/ ourVars SCmd + 6 + ! \ set # of sectors IOErr ( preset, if loop with retry is unsuccessful ) 10 0 DO ( retry max 10 times ) ourVars SCSIPseudo + ourVars SCmd + ourVars 60 r/w 10 SCSICommon 0= IF drop 0 leave THEN 1 (call) sysbeep \ just for debugging, \ beeps if SCSI did not complete successfully LOOP -> error -127 +> sectors sectors 1- 0< UNTIL ( transfer loop ) error dup 0= IF parBlk IOReqCount + @ -> bytes bytes parBlk IOActCount + ! \ we transferred the # of bytes requested bytes dce DCtlPosition + +! THEN ELSE IOErr THEN ; CODE DrvrInst ( unitNum | -- ) move.l (a6)+,d0 not.w d0 _DrvrInstall rts END-CODE CODE DrvrRem ( unitNum | -- ) move.l (a6)+,d0 not.w d0 _DrvrRemove rts END-CODE CODE openMe ( drvrName | result -- ) \ allocates a parameter block on the A7 stack and calls \ the _open trap. This is easier to do in assembly -- moveq.l#(IOParamBlkSize/2)-1,d0 @1 clr.w-(a7) dbra d0,@1 move.l a7,a0 move.l (a6)+,IONamePtr(a0) _Open add.w #IOParamBlkSize,a7 move.l d0,-(a6) rts END-CODE : RealInstall \ This routine is called by the system boot code with \ the SCSI ID of the disk in D5 and a pointer to its \ partition map in A0. We therefore need some special glue code. \ Note that Mach2 allows to do the stack parameter / local \ variable declaration after this glue code without any problems LINK A6,#-512 ( 512 bytes of local Forth stack ) MOVEM.L A2-A6/D2-D7,-(A7)( save registers ) MOVE.L A6,A3 ( setup local loop return stack ) SUBA.L #256,A3 ( in the low 256 local stack bytes ) MOVE.L A0,-(A6) ( partition table pointer ) MOVE.L D5,-(A6)( SCSI ID ) { partition ID | unitNum hdce dce ourVars pt -- } ID 32 + -> unitNum unitNum DrvrInst\ allocate DCE and install it unitNum 4 w* UTableBase @ + @ -> hdce \ dce handle hdce @ -> dce \ get dce pointer [‘] DiskDrvr dce ( DCtlDriver + ) ! \ put pointer to driver into dce [‘] DiskDrvr drvrFlags + w@ dce DCtlFlags + w! \ move driver flags, RAMbase should be cleared 0 dce DCtlDelay + w!\ no time needed yet [‘] DiskDrvr drvrEMask + @ dce DCtlEMask + ! \ move event mask and menu [‘] DiskDrvr drvrName + openMe \ try to open this driver IF ( not OK ) unitNum DrvrRem [‘] Scsidisk (call) DisposPtr bra @1 \ exit hack. \ This is the Mach2 equivalent of the \ Ugly Goto Statement in Pascal. \ Sorry, but it is so much easier this way... THEN hdce @ -> dce \ deref this handle again, may have changed dce dCtlStorage + @ -> ourVars ID ourVars ourID + w! partition IF \ well, we should have a non-NIL partition at least... partition ( PDSig + ) w@ PDSigWord = IF \ and it should be a Macintosh one. The NEW Apple drivers \ have a different sig word and DPM format that you \ might want to take into account here (see text). partition 2+ -> pt BEGIN pt PDFSID + @ ?dup WHILE \ otherwise no good partition found “tfs1 = IF ( correct file system ID ) pt @ ourVars Offset + ! pt 4 + @ xchg ( long drive size, hi word <-> lo word ) ourVars realSize + ! SysEvtMask w@ 0= IF \ we’re booting dce dCtlFlags + dup w@ $2000 OR swap w! ( set dNeedTime flag ) 1 dce dCtlDelay + w! 1 ourVars TickleFlag + c! THEN THEN 12 +> pt REPEAT THEN THEN @1 UNLK A2\ which was used for local variables MOVEM.L (A7)+,A2-A6/D2-D7( restore registers ) UNLK A6 RTS \ we stop here; the rest will be inaccessible junk (4 bytes). ; : DrOpen DA.prelude DiskOpen DA.epilogue ; : DrClose DA.prelude DiskClose DA.epilogue ; : DrCtl DA.prelude DiskControl DA.JIODone ; : DrStatus DA.prelude DiskStatus DA.JIODone ; : DrPrime DA.prelude DiskPrime DA.JIODone ; ‘ DrOpen ‘ DrPrime ‘ DrCtl ‘ DrStatus ‘ DrClose $6F00 0 0 0 ( flags delay mask menu ) “ .SCSIfth” ( name, MUST start with a period ) ;DA ‘ RealInstall ;XDEF \ ---------------------------------------------------- \ The following routines are to be added or replaced in the \ installer program from the previous column. Included is an \ installer that will directly move the Forth code to disk, without \ going through a resource, and some code to install the driver \ in memory for testing without writing it to the disk. The \ DDM and DPM definitions have been changed somewhat \ to accommodate the larger driver, and to have the partition start \ at the same place that Apple’s new SCSI driver expects it (so \ that you can replace the Forth driver easily by a new Apple \ driver in case you are fed up with this hack) \ Good luck. - JL - \ ---------------------------------------------------- hex : create.ddm ddm 200 0 fill 4552 ddm w! read.cap ddm 2+ w! ( block size ) ddm 4 + ! ( # of blocks ) 0 ddm 8 + w! ( device type ) 0 ddm A + w! ( device ID ) 10 ddm C + ! ( first data block ) 1 ddm 10 + w! ( one driver to follow ) 4 ddm 12 + ! ( driver start block ) A ddm 16 + w! ( driver is 10 blocks long ) 1 ddm 18 + w! ( and runs on Macintosh =1 ) ; : create.dpm dpm 200 0 fill 5453 dpm w! 10 dpm 2+ ! ( starting block of partition ) read.cap drop 10 - dpm 6 + ! ( # of blocks ) “tfs1 dpm A + ! ( TFS1 signature ) 0 dpm E + ! ; decimal : read.ddm 0 read.blk 2+ w! 0 read.blk 4 + c! 1 read.blk 5 + c! 120 read.blk myDisk @ ddm 512 doscsi.r 2drop ; : read.dpm 0 read.blk 2+ w! 1 read.blk 4 + c! 1 read.blk 5 + c! 120 read.blk myDisk @ dpm 512 doscsi.r 2drop ; : write.ddm 0 write.blk 2+ w! 0 write.blk 4 + c! 1 write.blk 5 + c! 120 write.blk myDisk @ ddm 512 doscsi.w 2drop ; : write.dpm 0 write.blk 2+ w! 1 write.blk 4 + c! 1 write.blk 5 + c! 120 write.blk myDisk @ dpm 512 doscsi.w 2drop ; : get.sdrv { | length -- length } [‘] scsidisk dup xlen dup -> length driver.block swap cmove length ; : write.sdrv { length | sectors } 0 write.blk 2+ w! 4 write.blk 4 + c! length 512 / 1+ dup write.blk 5 + c! -> sectors 120 write.blk myDisk @ driver.block sectors 512 * doscsi.w cr .” Driver written. Stat, Mess = “ . . ; : dmp { block# | -- } ( for easy testing of SCSI disk contents ) 0 read.blk 2+ w! block# read.blk 4 + c! 1 read.blk 5 + c! 120 read.blk myDisk @ ddm 512 doscsi.r 2drop ddm 20 dump ; .TRAP _newptr,sys $A51E $308 CONSTANT DQHeader 6 CONSTANT QTail VARIABLE syshp.drvr : install.driver { | dstart dlength dbytes pointer -- } read.ddm ddm 18 + @ -> dstart ddm 22 + w@ -> dlength cr .” Driver starts at sector “ dstart . .” and is “ dlength . .” sectors long.” dlength 512 * -> dbytes dstart 256 /mod read.blk 2+ w! read.blk 4 + c! dlength read.blk 5 + c! 120 read.blk myDisk @ driver.block dbytes doscsi.r cr .” Driver read; stat, mess = “ . . dbytes MOVE.L (A6)+,D0 _newptr,sys ( get memory block in system heap ) MOVE.L A0,-(A6) -> pointer pointer IFdriver.block pointer dbytes cmove pointer syshp.drvr ! ELSE .” Not enough system heap for installation.” cr THEN ; CODE call.driver MOVE.L D5,-(A7) MOVE.L (A6)+,D5 MOVE.L (A6)+,A0 execute MOVE.L (A7)+,D5 RTS END-CODE : mount.scsi install.driver read.dpm SysEvtMask @ 0 SysEvtMask ! syshp.drvr @ dpm myDisk @ call.driver SysEvtMask ! ; : zero.scsi DQHeader qTail + @ dQDrive + w@ ( drive # found ) cr .” Do you want to zero the directory of drive # “ dup . .” ? “ yesno if “ JL’s Hard Disk” call DIZero cr .” Result code = “ . cr then ; : mount cr .” Looking for SCSI devices...” get.disk cr .” SCSI drive found at address “ myDisk @ . cr show.cap cr .” format disk? “ yesno IF cr .” Do you REALLY want to erase this SCSI disk? “ yesno IF cr .” Reformatting disk... “ format THEN THEN modenoattn create.ddm create.dpm write.ddmwrite.dpm cr .” Device and partition descriptor maps written. “ get.sdrv cr .” Writing driver ... “ write.sdrv mount.scsi zero.scsi ; : install.mem { | dbytes pointer -- } get.sdrv [‘] scsidisk xlen dup -> dbytes MOVE.L (A6)+,D0 _newptr,sys ( get memory block in system heap ) MOVE.L A0,-(A6) -> pointer pointer IFdriver.block pointer dbytes cmove pointer syshp.drvr ! ELSE .” Not enough system heap for installation.” cr THEN ; : mount.mem install.mem read.dpm SysEvtMask @ 0 SysEvtMask ! syshp.drvr @ dpm myDisk @ call.driver SysEvtMask ! ;
- SPREAD THE WORD:
- Slashdot
- Digg
- Del.icio.us
- Newsvine