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108 lines
2.3 KiB
Plaintext
108 lines
2.3 KiB
Plaintext
;**************************************************************************
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;* CP/M 3 BIOS for Z80em86 Z80 CPU emulator *
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;* *
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;* Floppy disk driver *
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;* *
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;* Copyright (C) 1992-2009 Stewart Kay *
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;**************************************************************************
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;
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; ChangeLog (most recent entries are at top)
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; ------------------------------------------
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; v1.0.0 - 16 February 2009, S.J.Kay
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; - Prepare for public release.
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;
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; v1.00 - 17 April 1995, S.J.Kay
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; - Undocumented changes.
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;
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; v0.00 - 1992, S.J.Kay
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; - Initial creation date.
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; Entry point 1 : ifdsk - Initialize
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; Entry point 2 : lfdsk - Login
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; Entry point 3 : wfdsk - Write sector
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; Entry point 4 : rfdsk - Read sector
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.z80
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;
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maclib TPORTS.LIB
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maclib ASMTYPE.LIB
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;
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public ifdsk, lfdsk, rfdsk, wfdsk
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;
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extrn @dtbl, @adrv, @rdrv, @dbnk, @dma, @trk, @sect, @cnt
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;
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dseg ;banked memory
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; Entry point 1 - Initialize floppy drive
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ifdsk: ret
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; Entry point 2 - Login floppy drive
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lfdsk: ret
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; Entry point 3 - Write floppy sector
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wfdsk: or 0ffh ;write operation flag value
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jp fdisk
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; Entry point 4 - Read floppy sector
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rfdsk: xor a ;read operation flag value
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fdisk: push af ;save operation flag
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ld a,(@rdrv)
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ld h,a
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ld l,0 ;side #0
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ld a,(@trk)
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sla h
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jp c,side0 ;single sided disk if carry
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sla h
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jp c,dsdisk ;double sided disk if carry
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cp 40
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jp c,side0 ;side 0 of up-down if carry
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ld b,a ;side 1 of up-down
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ld a,79
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sub b
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jp side1
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dsdisk: srl a
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jp nc,side0
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side1: ld l,1 ;set side #1
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side0: ld (track),a
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ld a,l
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ld (side),a
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ld hl,12 ;offset into DPH for DPB address
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add hl,de
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ld e,(hl) ;LSB of DPB address
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inc hl
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ld d,(hl) ;MSB of DPB address
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ld hl,15 ;offset into DPB for PSH
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add hl,de
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ld a,(hl)
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ld (secsze),a ;sector size code
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ld a,(@rdrv)
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ld e,a ;contains physical select code
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ld a,(side)
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ld d,a
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ld a,(track)
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ld b,a
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ld a,(@sect)
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ld c,a
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if banked
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ld a,(@dbnk)
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out (bnkdma),a
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endif
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ld hl,(@dma)
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pop af ;restore operation flag
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ld a,(secsze)
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jp z,readop
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out (wrflop),a
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jp result
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readop: out (rdflop),a
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result: or a
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ret z
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ld a,1
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ret
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;
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secsze: db 0
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side: db 0
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track: db 0
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;
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end
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