mirror of
https://github.com/wwarthen/RomWBW.git
synced 2026-02-06 14:11:48 -06:00
bccd80882c
Jörg Linder has disassembled and thoroughly commented a great deal of the BPBIOS binaries. This was an incredible amount of work. I have added all of these to the RomWBW build scripts and will ultimately integrate them more completely.
410 lines
11 KiB
Z80 Assembly
410 lines
11 KiB
Z80 Assembly
TITLE "B/P Bios HD drive partition display"
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;************************************************************************
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;* S H O W H D *
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;* Display DPH and DPB data for making B/P HD Partition data the same *
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;* by Harold F. Bower and Cameron W. Cotrill *
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;*----------------------------------------------------------------------*
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;* Disassembly: jxl Jan 2025 *
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;* public release 1.0 Apr 2025 *
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;* see remarks at the end *
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;*----------------------------------------------------------------------*
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;* LINK with Version 4 libraries: SYSLIB *
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;* *
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;* A>Z80ASM SHOWHD/RS *
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;* A>SLRNK SHOWHD/N,/A:100,/D:064D,SHOWHD,SYSLIBS/S,/E *
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;************************************************************************
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VER EQU 10
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REV EQU ' '
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DATE MACRO
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DEFB '2 Nov 91'
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ENDM
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CTRLC EQU 03H ; Control-C character
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BEL EQU 07H ; Bell character
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TAB EQU 09H ; Tab character
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LF EQU 0AH ; Line Feed character
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CR EQU 0DH ; Carriage Return character
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ESC EQU 1BH ; Escape character
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CPMBIOS EQU 0 ; CP/M BIOS warm boot (JP)
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CPMFCB EQU 5CH ; CP/M standard FCB #1 (+1 filename, +9 filetype)
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; For SYSLIB make visible...
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PUBLIC COUT
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; From SYSLIB Get..
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EXTRN EPRINT, BOUT, CAPINE, PAFDC, PHLFDC, PA2HC
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;::::: PROGRAM START
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ORG 100H
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CSEG
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SHOWHD: JP START ; bypass header
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DEFB 'Z3ENV' ; this is (not really) a Z3CPR utility
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DEFB 1 ; show external environment
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ENVADR: DEFW 0 ; addr of Z3 environment
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START: LD (STACK),SP
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LD SP,STACK
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CALL EPRINT
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DEFB CR,LF,'Show Hard Drive Partition Data - '
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DATE
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DEFB CR,LF
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DEFB 0
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LD A,(CPMFCB+1) ; check first char of cmdline
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CP '/' ; is this a help request ?
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JP Z,HELP ; ..if so, jump
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START0: CALL EPRINT
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DEFB CR,LF,'Enter Drive Letter [A..P] : '
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DEFB 0
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CALL CAPINE ; get user input
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CP CTRLC ; is it <Ctrl-C> ?
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JP Z,0 ; ..abort
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CP ESC ; is it <ESC> ?
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JP Z,0 ; ..abort
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CP 'A' ; below ascii 'A' ?
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JR C,START0 ; ..if so, loop ask for new input
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CP 'P'+1 ; greater than ascii 'P' ?
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JR NC,START0 ; ..if so, loop ask for new input
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LD (DRLTR),A ; store drive letter
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CALL EPRINT
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DEFB CR,LF,LF,'Drive: '
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DEFB 0
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CALL COUT ; display drive
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CALL EPRINT
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DEFB CR,LF,TAB,'DPH Info',TAB,TAB,'BPCNFG Info',CR,LF
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DEFB 0
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CALL GDPHADR ; get DPH addr for selected Disk drive
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LD (DPHADR),HL ; ..and store it
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LD A,H ; check if invalid (= zero)
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OR L
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JR NZ,PDSKDAT ; ..if not, skip over
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CALL EPRINT
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DEFB CR,LF,BEL,'+++ Invalid Drive : '
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DEFB 0
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LD A,(DRLTR) ; get drive letter
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CALL COUT ; ..and display it
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JP START0 ; then loop to ask for new input
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;::::: DISPLAY DISK DRIVE DATA
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PDSKDAT: LD DE,10 ; offset in DPH to DPB addr
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ADD HL,DE
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LD E,(HL) ; DPB addr in DE
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INC HL
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LD D,(HL)
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EX DE,HL ; swap regs
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LD (DPBADR),HL ; ..and store DPB addr
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CALL EPRINT
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DEFB CR,LF,LF,' Sectors/Track = '
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DEFB 0
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LD E,(HL) ; get Sect/Trk from DPB in DE
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INC HL
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LD D,(HL)
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INC HL
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EX DE,HL ; swap regs
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CALL PHLFDC ; ..and display (as decimal)
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SRL H ; divide by 2
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RR L
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SRL H ; .. /4
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RR L
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SRL H ; .. /8
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RR L
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LD (KBTRK),HL ; store kByte/Trk
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EX DE,HL ; swap regs
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CALL P2TAB
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CALL EPRINT
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DEFB '(same)',CR,LF,' Blk Shift Fctr = '
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DEFB 0
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LD A,(HL) ; get next byte from DPB (= BSH, Block Shift Factor)
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INC HL ; move ptr fwd
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CALL PAFDC ; display BSH
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CALL P2TAB
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SUB 3 ; BSH -3
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LD B,A ; use as counter for multiplication
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LD (BSH3),A ; ..and also store it
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LD A,1 ; set initial value
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JR Z,PBLKSIZ ; if BSH -3 = 0, skip over
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BLKSZLP: ADD A,A ; *2
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DJNZ BLKSZLP ; loop
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PBLKSIZ: CALL PAFDC ; display block size
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; (BSH= 3 -> 1k, 4 -> 2k, ... 8 -> 32k)
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CALL EPRINT
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DEFB 'k/Block',CR,LF,' Block Mask = '
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DEFB 0
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LD A,(HL) ; next byte from DPB (= BSM, Block Mask)
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INC HL
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CALL PAFDC ; ..display it
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CALL EPRINT
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DEFB CR,LF,' Extent Mask = '
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DEFB 0
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LD A,(HL) ; next byte from DPB (= EXM, Extent Mask)
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INC HL
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CALL PAFDC ; ..display it
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CALL EPRINT
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DEFB CR,LF,' Disk Blocks-1 = '
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DEFB 0
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LD E,(HL) ; next 16-bit value from DPB in DE
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INC HL ; (= Disk Size in BLS units -1)
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LD D,(HL)
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INC HL
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EX DE,HL ; swap regs
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CALL PHLFDC ; display value
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CALL P2TAB
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INC HL ; +1 (= Disk Size)
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LD A,(BSH3) ; get BSH-3
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LD B,A ; set as initial loop counter
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OR A ; check if zero (means single density 1k/block)
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LD A,0 ; nullify A
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JR Z,PDSKCAP ; ..if already zero, no more calc needed
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DSKCLP: ADD HL,HL ; double HL (2, 4, 8 etc. k/block)
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ADC A,0 ; a power-of-two multiple
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DJNZ DSKCLP ; ..and loop
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LD (DCAPH),A ; store disk capacity in kByte
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LD (DCAPML),HL ; as 24-bit value
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PDSKCAP: CALL PDSKSZ ; ..and display it
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CALL EPRINT
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DEFB 'k Total ('
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DEFB 0
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PUSH DE
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LD DE,(KBTRK) ; kByte/Trk
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LD HL,(DCAPML) ; disk capacity in kByte
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LD A,(DCAPH)
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LD BC,-1 ; set initial counter value
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OR A
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DSKTRLP: INC BC ; increase counter (quotient)
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SBC HL,DE ; divide by subtraction
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SBC A,0 ; check for underflow
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JR NC,DSKTRLP ; ..and loop while more to go
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LD H,B ; result in HL
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LD L,C
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CALL PHLFDC ; ..display it
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CALL EPRINT
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DEFB ' Tracks)'
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DEFB 0
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POP DE ; restore DPB ptr
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EX DE,HL ; swap to HL
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CALL EPRINT
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DEFB CR,LF,' Max Dirs - 1 = '
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DEFB 0
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LD E,(HL) ; get next 16-bit value from DPB in DE
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INC HL ; (= Dir Max -1)
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LD D,(HL)
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INC HL
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EX DE,HL ; swap regs
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CALL PHLFDC ; ..and display value
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CALL P2TAB
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INC HL ; +1 (= Dir Max)
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CALL PHLFDC ; ..and display, too
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EX DE,HL
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CALL EPRINT
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DEFB ' Dir Entries',CR,LF,' Alloc bytes = '
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DEFB 0
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LD A,(HL) ; next byte from DPB (= AL0, Allocation byte 0)
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INC HL
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LD D,(HL) ; (= AL1, Allocation byte 1)
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INC HL
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CALL PA2HC ; display AL0 as hex
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CALL EPRINT
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DEFB 'H, '
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DEFB 0
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LD A,D ; AL1 in A
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CALL PA2HC ; ..and display as hex
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CALL EPRINT
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DEFB 'H',CR,LF,' Check Size = '
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DEFB 0
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LD E,(HL) ; next 16-bit value from DPB in DE
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INC HL ; (= CKS, Check Size)
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LD D,(HL)
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INC HL
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EX DE,HL ; swap regs
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CALL PHLFDC ; display value
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EX DE,HL ; swap regs back
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CALL EPRINT
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DEFB CR,LF,' Track Offset = '
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DEFB 0
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LD E,(HL) ; next 16-bit value from DPB in DE
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INC HL ; (= Track Offset)
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LD D,(HL)
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INC HL
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EX DE,HL ; swap regs
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CALL PHLFDC ; display value
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EX DE,HL ; swap regs back
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CALL P2TAB
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CALL EPRINT
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DEFB '(same)',CR,LF
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DEFB 0
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JP 0 ; and exit with Warm Boot
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; print 2 tabs on CON:
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P2TAB: PUSH AF
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LD A,TAB ; <TAB> in A
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CALL COUT ; display on CON:
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CALL COUT ; 2x
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POP AF ; restore
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RET
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;::::: HELP
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HELP
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CALL EPRINT
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DEFB CR,LF,'SHOWHD - Display DPH and DPB data for '
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DEFB 'specified drive for making B/P',CR,LF
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DEFB ' Hard Drive Partition data the same as '
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DEFB 'an operating system.',CR,LF,LF
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DEFB ' Syntax:',CR,LF,LF
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DEFB TAB,'SHOWHD <-- Execute program interactively',CR,LF
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DEFB TAB,'SHOWHD // <-- Display this message',CR,LF
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DEFB 0
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LD SP,(STACK)
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RET
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;::::: SUPPORT FUNCTIONS
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; get addr of Disk Parameter Header (DPH)
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; in: Disk drive letter in mem variable
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; out: HL= addr DPH
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GDPHADR: LD HL,(CPMBIOS+1) ; addr Bios fn #1 (WBOOT)
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LD L,9*3 ; adjust ptr to fn #9 (SELDSK)
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LD A,(DRLTR) ; get drive letter
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SUB 'A' ; ..and convert to number
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LD C,A ; copy to reg. C (for Bios call)
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LD E,0
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JP (HL) ; "call" Bios fn #9 and let return from there
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; (SELDSK returns DPH addr in HL)
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; print disk size to CON: (capacity of a drive in kB)
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; output as decimal with provision for 3-byte values - see ZXD21.Z80 PRBIG
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; in: 24-bit value to print in A,H,L
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PDSKSZ: PUSH DE ; save regs
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PUSH BC
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EX AF,AF' ; swap AF
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PUSH AF ; save it
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EX AF,AF' ; ..and swap back
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LD B,0
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LD C,-1 ; set initial result
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LD DE,86A0H ; 100,000 = 0x0186A0, set lower 2 bytes
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OR A ; clear C-Flag
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PDSKSZ0: INC C ; accumulate count
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SBC HL,DE ; subtract lower 2 bytes
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SBC A,1 ; ..and upper byte
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JR NC,PDSKSZ0 ; loop till done
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ADD HL,DE ; adjust underflow
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ADC A,1
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CALL PHLD1
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LD DE,10000 ; print 10000's
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CALL PHLD
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LD DE,1000 ; print 1000's
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CALL PHLD
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LD DE,100 ; print 100's
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CALL PHLD
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LD DE,10 ; print 10's
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CALL PHLD
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LD A,L ; print 1's
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CALL PHLD2
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POP AF ; restore regs
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EX AF,AF' ; swap
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POP BC ; ..and also restore other regs
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POP DE
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RET
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; print content of HL to CON: as decimal
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; divide HL by DE, convert remainder to ascii digit and print it
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; (similar to SYSLIB's PHLFDC/PHDC1 - see ZXD21.Z80 DECDSP)
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; in: HL= value, DE= divisor
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PHLD: LD C,-1 ; set initial count
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OR A ; clear C-Flag
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PHLD0: INC C ; accumulate count
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SBC HL,DE ; divide by subtraction
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SBC A,0
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JR NC,PHLD0 ; ..and loop while more to go
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ADD HL,DE ; compensate underflow
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ADC A,0
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PHLD1: EX AF,AF' ; swap to retain flags
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LD A,C ; get result (quotient)
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OR A ; is it zero ?
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JR NZ,PHLD2 ; ..if not, skip over
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OR B ; get prior digit print flag
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JR Z,PHLD3 ; ..if anything printed yet, jump
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XOR A ; else, print a zero
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PHLD2: ADD A,'0' ; convert to ascii
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LD B,A ; remember for next loop
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CALL COUT ; ..and display it
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PHLD3: EX AF,AF' ; swap regs back
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RET
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; intercept COUT to re-route SYSLIB calls to to BOUT
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; --> declare COUT as PUBLIC, and do _not_ import from SYSLIB
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COUT: JP BOUT
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;:::::::::::::::::::::::::::::::::::::::::::::::::::::
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; SYSLIB - 0x0530
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; end addr 0x064d (begin DSEG)
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;:::::::::::::::::::::::::::::::::::::::::::::::::::::
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;::::: RAM STORAGE
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DSEG
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KBTRK: DEFW 0 ; kByte/Trk (Sect/Trk divided by 8)
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BSH3: DEFB 0 ; BSH -3 (Block Shift Factor -3)
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; disk capacity as 24-bit value
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DCAPH: DEFB 0 ; high byte
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DCAPML: DEFW 0 ; middle and low byte
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DRLTR: DEFB 0 ; drive letter (entered by user)
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DPHADR: DEFW 0 ; addr DPH (not used)
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DPBADR: DEFW 0 ; addr DPB (not used)
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DEFS 30H ; room for stack
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STACK: DEFW 0 ; stack storage location
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END
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;************************************************************************
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; Remarks jxl:
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; SHOWHD.COM, included in available B/P Bios package(s), was dis-
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; assembled and extensively commented. Labels are up to seven chars long
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; to comply with M-REL standards. However, it is recommended to use SLR
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; tools that support labels up to sixteen chars.
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; In its current state, the compiled/linked file matches exactly the
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; original SHOWHD.COM, i.e. no changes to the source were made.
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;
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; The program is not very complex. However, one thing might be worth
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; to be pointed out: SYSLIB's routine COUT is replaced with an own
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; implementation. While it is just a re-routing to another SYSLIB routine,
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; it shows how simply this can be achieved. Bear in mind that _all_
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; SYSLIB routines calling COUT would now call the local implementation
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; instead. With this technique existing routines can be modified without
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; rewriting them entirely.
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;************************************************************************
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