TITLE HRDDRV.SYS for the ALTOS ACS-86C.
; Hard Disk Drive for Version 2.x of MSDOS.
; Constants for commands in Altos ROM.
ROM_CONSTA EQU 01 ;Return status AL of console selected in CX.
ROM_CONIN EQU 02 ;Get char. from console in CX to AL
ROM_CONOUT EQU 03 ;Write char. in DL to console in CX.
ROM_PMSG EQU 07 ;Write string ES:DX to console in CX.
ROM_DISKIO EQU 08 ;Perform disk I/O from IOPB in ES:CX.
ROM_INIT EQU 10 ;Returns boot console and top memory ES:DX.
CODE SEGMENT
ASSUME CS:CODE,DS:CODE,ES:CODE,SS:CODE
ORG 0 ;Starts at an offset of zero.
PAGE
SUBTTL Device driver tables.
;-----------------------------------------------+
; DWORD pointer to next device | 1 word offset.
; (-1,-1 if last device) | 1 word segement.
;-----------------------------------------------+
; Device attribute WORD ; 1 word.
; Bit 15 = 1 for chacter devices. ;
; 0 for Block devices. ;
; ;
; Charcter devices. (Bit 15=1) ;
; Bit 0 = 1 current sti device. ;
; Bit 1 = 1 current sto device. ;
; Bit 2 = 1 current NUL device. ;
; Bit 3 = 1 current Clock device. ;
; ;
; Bit 13 = 1 for non IBM machines. ;
; 0 for IBM machines only. ;
; Bit 14 = 1 IOCTL control bit. ;
;-----------------------------------------------+
; Device strategy pointer. ; 1 word offset.
;-----------------------------------------------+
; Device interrupt pointer. ; 1 word offset.
;-----------------------------------------------+
; Device name field. ; 8 bytes.
; Character devices are any valid name ;
; left justified, in a space filled ;
; field. ;
; Block devices contain # of units in ;
; the first byte. ;
;-----------------------------------------------+
DSKDEV: ;Header for hard disk driver.
DW -1,-1 ;Last device
DW 2000H ;Is a block device
DW STRATEGY
DW DSK_INT
MEMMAX DB 1 ;Number of Units
PAGE
SUBTTL Dispatch tables for each device.
DSK_TBL:DW DSK_INI ;0 - Initialize Driver.
DW MEDIAC ;1 - Return current media code.
DW GET_BPB ;2 - Get Bios Parameter Block.
DW CMDERR ;3 - Reserved. (currently returns error)
DW DSK_RED ;4 - Block read.
DW BUS_EXIT ;5 - (Not used, return busy flag)
DW EXIT ;6 - Return status. (Not used)
DW EXIT ;7 - Flush input buffer. (Not used.)
DW DSK_WRT ;8 - Block write.
DW DSK_WRV ;9 - Block write with verify.
DW EXIT ;10 - Return output status.
DW EXIT ;11 - Flush output buffer. (Not used.)
DW EXIT ;12 - IO Control.
PAGE
SUBTTL Strategy and Software Interrupt routines.
;Define offsets for io data packet
IODAT STRUC
CMDLEN DB ? ;LENGTH OF THIS COMMAND
UNIT DB ? ;SUB UNIT SPECIFIER
CMD DB ? ;COMMAND CODE
STATUS DW ? ;STATUS
DB 8 DUP (?)
MEDIA DB ? ;MEDIA DESCRIPTOR
TRANS DD ? ;TRANSFER ADDRESS
COUNT DW ? ;COUNT OF BLOCKS OR CHARACTERS
START DW ? ;FIRST BLOCK TO TRANSFER
IODAT ENDS
PTRSAV DD 0 ;Strategy pointer save.
;
; Simplistic Strategy routine for non-multi-Tasking system.
;
; Currently just saves I/O packet pointers in PTRSAV for
; later processing by the individual interrupt routines.
;
STRATP PROC FAR
STRATEGY:
MOV WORD PTR CS:[PTRSAV],BX
MOV WORD PTR CS:[PTRSAV+2],ES
RET
STRATP ENDP
;
; Ram memory driver interrupt routine for processing I/O packets.
;
DSK_INT:
PUSH SI ;Save SI from caller.
MOV SI,OFFSET DSK_TBL
;
; Common program for handling the simplistic I/O packet
; processing scheme in MSDOS 2.0
;
ENTRY: PUSH AX ;Save all nessacary registers.
PUSH CX
PUSH DX
PUSH DI
PUSH BP
PUSH DS
PUSH ES
PUSH BX
LDS BX,CS:[PTRSAV] ;Retrieve pointer to I/O Packet.
MOV AL,[BX.UNIT] ;AL = Unit code.
MOV AH,[BX.MEDIA] ;AH = Media descriptor.
MOV CX,[BX.COUNT] ;CX = Contains byte/sector count.
MOV DX,[BX.START] ;DX = Starting Logical sector.
XCHG DI,AX ;Save Unit and Media Temporarily.
MOV AL,[BX.CMD] ;Retrieve Command type. (1 => 11)
XOR AH,AH ;Clear upper half of AX for calculation.
ADD SI,AX ;Compute entry pointer in dispatch table.
ADD SI,AX
CMP AL,11 ;Verify that not more than 11 commands.
JA CMDERR ;Ah, well, error out.
XCHG AX,DI
LES DI,[BX.TRANS] ;DI contains addess of Transfer address.
;ES contains segment.
PUSH CS
POP DS ;Data segment same as Code segment.
JMP [SI] ;Perform I/O packet command.
PAGE
SUBTTL Common error and exit points.
BUS_EXIT: ;Device busy exit.
MOV AH,00000011B ;Set busy and done bits.
JMP SHORT EXIT1
CMDERR: MOV AL,3 ;Set unknown command error #.
;
; Common error processing routine.
; AL contains actual error code.
;
; Error # 0 = Write Protect violation.
; 1 = Unkown unit.
; 2 = Drive not ready.
; 3 = Unknown command in I/O packet.
; 4 = CRC error.
; 5 = Bad drive request structure length.
; 6 = Seek error.
; 7 = Unknown media discovered.
; 8 = Sector not found.
; 9 = Printer out of paper.
; 10 = Write fault.
; 11 = Read fault.
; 12 = General failure.
;
ERR_EXIT:
MOV AH,10000001B ;Set error and done bits.
STC ;Set carry bit also.
JMP SHORT EXIT1 ;Quick way out.
EXITP PROC FAR ;Normal exit for device drivers.
EXIT: MOV AH,00000001B ;Set done bit for MSDOS.
EXIT1: LDS BX,CS:[PTRSAV]
MOV [BX.STATUS],AX ;Save operation compete and status.
POP BX ;Restore registers.
POP ES
POP DS
POP BP
POP DI
POP DX
POP CX
POP AX
POP SI
RET ;RESTORE REGS AND RETURN
EXITP ENDP
PAGE
subttl Hard Disk drive control.
;
; Read command = 09 hex.
; Write command = 02 hex.
; Seek command = 10 hex.
; Recal command = 20 hex.
; Rezero command = 40 hex.
; Reset command = 80 hex.
;
; Busy = 01 hex.
; Operation Complete = 02 hex.
; Bad Sector = 04 hex.
; Record Not found = 08 hex.
; CRC error = 10 hex.
; (not used) = 20 hex.
; Write fault = 40 hex.
; Drive Ready = 80 hex.
;
hd_read equ 09h
hd_writ equ 02h
hd_wmsk equ 5dh
hd_rmsk equ 9ch
page
SUBTTL Altos monitor ram and 8089 IOPB structures.
;
; Structure to reference 8089 and ROM command table.
;
SIOPB STRUC
DB 4 DUP (?) ;Monitor Use Only
OPCODE DB ? ;I/O operation code.
DRIVE DB ? ;Logical drive spec.
TRACK DW ? ;Logical track number.
HEAD DB ? ;Logical head number.
SECTOR DB ? ;Logical sector to start with.
SCOUNT DB ? ;Number of logical sectors in buffer.
RETCODE DB ? ;Error code after masking.
RETMASK DB ? ;Error mask.
RETRIES DB ? ;Number of retries before error exit.
DMAOFF DW ? ;Buffer offset address.
DMASEG DW ? ;Buffer segment.
SECLENG DW ? ;Sector Length.
DB 6 DUP (?) ;8089 use only.
SIOPB ENDS
IOPB SIOPB <,0,0,0,0,0,0,0,0,0,0,0,0,>
PAGE
SUBTTL Common Drive parameter block definitions on Altos.
DBP STRUC
JMPNEAR DB 3 DUP (?) ;Jmp Near xxxx for boot.
NAMEVER DB 8 DUP (?) ;Name / Version of OS.
;------- Start of Drive Parameter Block.
SECSIZE DW ? ;Sector size in bytes. (dpb)
ALLOC DB ? ;Number of sectors per alloc. block. (dpb)
RESSEC DW ? ;Reserved sectors. (dpb)
FATS DB ? ;Number of FAT's. (dpb)
MAXDIR DW ? ;Number of root directory entries. (dpb)
SECTORS DW ? ;Number of sectors per diskette. (dpb)
MEDIAID DB ? ;Media byte ID. (dpb)
FATSEC DW ? ;Number of FAT Sectors. (dpb)
;------- End of Drive Parameter Block.
SECTRK DW ? ;Number of Sectors per track.
HEADS DW ? ;Number of heads per cylinder.
HIDDEN DW ? ;Number of hidden sectors.
DBP ENDS
HDDRIVE DBP <,,512,4,0,2,256,4000,0F5H,3,12,4,0>
INI_TAB DW OFFSET HDDRIVE.SECSIZE
PAGE
SUBTTL Media check routine
;
; Media check routine.
; On entry:
; AL = memory driver unit number.
; AH = media byte
; On exit:
;
; [MEDIA FLAG] = -1 (FF hex) if disk is changed.
; [MEDIA FLAG] = 0 if don't know.
; [MEDIA FLAG] = 1 if not changed.
;
MEDIAC: LDS BX,CS:[PTRSAV]
MOV BYTE PTR [BX.TRANS],1
JMP EXIT
PAGE
SUBTTL Build and return Bios Parameter Block for a diskette.
;
; Build Bios Parameter Blocks.
;
; On entry: ES:BX contains the address of a scratch sector buffer.
; AL = Unit number.
; AH = Current media byte.
;
; On exit: Return a DWORD pointer to the associated BPB
; in the Request packet.
;
GET_BPB:
MOV SI,OFFSET HDDRIVE+11
LDS BX,CS:[PTRSAV]
MOV WORD PTR [BX.COUNT],SI
MOV WORD PTR [BX.COUNT+2],CS
JMP EXIT
PAGE
SUBTTL MSDOS 2.x Disk I/O drivers.
;
; Disk READ/WRITE functions.
;
; On entry:
; AL = Disk I/O driver number
; AH = Media byte.
; ES = Disk transfer segment.
; DI = Disk transfer offset in ES.
; CX = Number of sectors to transfer
; DX = Logical starting sector.
;
; On exit:
; Normal exit through common exit routine.
;
; Abnormal exit through common error routine.
;
DSK_RED:
MOV AH,HD_READ
JMP SHORT DSK_COM
DSK_WRV:
DSK_WRT:
MOV AH,HD_WRIT
DSK_COM:
MOV SI,OFFSET HDDRIVE ;Keeps code size down.
MOV [IOPB.DMASEG],ES
MOV [IOPB.DMAOFF],DI
MOV DI,[SI.SECSIZE]
MOV [IOPB.SECLENG],DI
MOV [IOPB.RETRIES],1
MOV [IOPB.RETMASK],05DH ;Error return mask.
MOV [IOPB.OPCODE],AH
MOV [IOPB.DRIVE],4 ;Drive 4 is only available.
ADD DX,[SI.HIDDEN] ;Account for invisible sectors.
MOV BP,CX ;Save number of sectors to R/W
DSK_IO1:
PUSH DX ;Save starting sector.
MOV AX,DX
MOV DX,0 ;32 bit divide coming up.
MOV CX,[SI.SECTRK]
DIV CX ;Get track+head and start sector.
MOV [IOPB.SECTOR],DL ;Starting sector.
MOV BL,DL ;Save starting sector for later.
MOV DX,0
MOV CX,[SI.HEADS]
DIV CX ;Compute head we are on.
MOV [IOPB.HEAD],DL
MOV [IOPB.TRACK],AX ;Track to read/write.
MOV AX,[SI.SECTRK] ;Now see how many sectors
INC AL ; we can burst read.
SUB AL,BL ;BL is the starting sector.
MOV AH,0
POP DX ;Retrieve logical sector start.
CMP AX,BP ;See if on last partial track+head.
JG DSK_IO2 ;Yes, on last track+head.
SUB BP,AX ;No, update number of sectors left.
ADD DX,AX ;Update next starting sector.
JMP SHORT DSK_IO3
DSK_IO2:MOV AX,BP ;Only read enough of sector
MOV BP,0 ;to finish buffer and clear # left.
DSK_IO3:MOV [IOPB.SCOUNT],AL
MOV DI,AX ;Save number sectors for later.
MOV BX,ROM_DISKIO
MOV CX,OFFSET IOPB
PUSH CS
POP ES
CALL ROM_CALL ;Do disk operation.
MOV AL,[IOPB.RETCODE] ;Get error code.
OR AL,AL
JNZ DERROR
MOV AX,DI ;Retrieve number of sectors read.
MOV CX,[SI.SECSIZE] ;Number of bytes per sector.
PUSH DX
MUL CX
POP DX
TEST AL,0FH ;Make sure no strange sizes.
JNZ SERR1
MOV CL,4
SHR AX,CL ;Convert number of bytes to para.
ADD AX,[IOPB.DMASEG]
MOV [IOPB.DMASEG],AX
OR BP,BP
JNZ DSK_IO1 ;Still more to do.
MOV AL,0
JMP EXIT ;All done.
SERR1: MOV AL,12
JMP ERR_EXIT
PAGE
SUBTTL Disk Error processing.
;
; Disk error routine.
;
DERROR:
LDS BX,CS:[PTRSAV]
MOV [BX.COUNT],0
PUSH CS
POP DS
MOV BL,-1
MOV AH,AL
MOV BH,14 ;Lenght of table.
MOV SI,OFFSET DERRTAB
DERROR2:INC BL ;Increment to next error code.
LODS BYTE PTR CS:[SI]
CMP AH,AL ;See if error code matches disk status.
JZ DERROR3 ;Got the right error, exit.
DEC BH
JNZ DERROR2 ;Keep checking table.
MOV BL,12 ;Set general type of error.
DERROR3:MOV AL,BL ;Now we've got the code.
JMP ERR_EXIT
DERRTAB DB 00H ; 0. Write protect error
DB 00H ; 1. Unknown unit.
DB 00H ; 2. Not ready error.
DB 00H ; 3. Unknown command.
DB 10H ; 4. CRC error
DB 00H ; 5. Bad drive request.
DB 00H ; 6. Seek error
DB 00H ; 7. Unknown media.
DB 08H ; 8. Sector not found
DB 00H ; 9. (Not used.)
DB 40H ;10. Write fault.
DB 04H ;11. Read fault.
DB 01H ;12. General type of failure.
PAGE
SUBTTL Common ROM call routine.
;
; Save all registers except CX, BX and AX.
ROMRTN DD 0FE000000H ;Main ROM entry point.
ROM_CALL:
PUSH DI
PUSH SI
PUSH BP
PUSH DX
PUSH ES
CALL CS:DWORD PTR [ROMRTN]
POP ES
POP DX
POP BP
POP SI
POP DI
RET
PAGE
SUBTTL Hard Disk Drive initalization routine.
DSK_INI:
LDS BX,CS:[PTRSAV]
MOV BYTE PTR [BX.MEDIA],1
MOV WORD PTR [BX.TRANS],OFFSET DSK_INI
MOV WORD PTR [BX.TRANS+2],CS
MOV WORD PTR [BX.COUNT],OFFSET INI_TAB
MOV WORD PTR [BX.COUNT+2],CS
JMP EXIT
CODE ENDS
END
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