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https://github.com/wwarthen/RomWBW.git
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ee0fac37f9
Adding infrastructure for partition table support. Backward compatible. Not ready for end user usage yet. Bumped version to 3.1.1 to demarcate this change.
101 lines
2.1 KiB
Z80 Assembly
101 lines
2.1 KiB
Z80 Assembly
title 'bank & move module for CP/M3 linked BIOS'
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cseg
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public ?move,?xmove,?bank,?bnkxlt
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public ?mvinit,@hbbio,@hbusr
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extrn @cbnk
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?mvinit:
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ld bc,0F8F2h ; HBIOS GET BNKINFO
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;rst 08 ; D: BIOS Bank, E: User Bank
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call 0FFF0h ; D: BIOS Bank, E: User Bank
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ld a,d
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ld (@hbbio),a
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ld a,e
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ld (@hbusr),a
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ret
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?xmove:
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ld (movbnks),bc ; save source & dest banks
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or 0FFh ; flag interbank move type
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ld (movtyp),a ; save it
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ret
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?move:
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ld a,(movtyp) ; get move type flag
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or a ; set flags
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jr nz,xbnkmov ; if so, go to interbank move
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; Intrabank move
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ex de,hl ; we are passed source in DE and dest in HL
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ldir ; use Z80 block move instruction
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ex de,hl ; need next addresses in same regs
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ret
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xbnkmov:
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;ld ix,8888H
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;halt
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; Interbank move
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xor a ; zero
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ld (movtyp),a ; clear move type flag
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ld a,(srcbnk)
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call ?bnkxlt
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ld (0FFE4h),a
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ld a,(dstbnk)
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call ?bnkxlt
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ld (0FFE7h),a
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ex de,hl ; swap address regs for call
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call 0FFF6h ; HBIOS BNKCPY
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ex de,hl ; next addresses in same regs
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ret
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?bank:
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call ?bnkxlt ; xlat to HBIOS bank id
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jp 0FFF3h ; do it and return
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;
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; Convert from CPM3 bank id to HBIOS bank id.
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; CPM3 wants TPA for it's bank 0, so that is special
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; case mapping to HBIOS BID_USR (8Eh). Otherwise, we index
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; down below BID_HBIOS (8Dh). So CPM3 bank usage grows
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; downward.
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;
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; CPM3 HBIOS Typical
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; ------------ -------------- -------
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; COMMON BID_COM 8Fh
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; 0: OS/BUFS BID_USR 8Eh
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; BID_BIOS 8Dh
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; 1: TPA BID_AUX 8Ch
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; 2: BUFS BID_AUX-1 8Bh
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; 3: BUFS BID_AUX-2 8Ah
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; 4: BUFS BID_AUX-3 89h
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; 5: BUFS BID_AUX-4 88h
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;
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; N.B., Below BID_AUX is considered RAM disk bank. Need to
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; make sure RAM disk is kept small enough to stay below
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; banks used for OS buffers.
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;
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; @hbbio & @hbusr are dynamically updated during init
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; to adjust for real size of RAM in system
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;
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?bnkxlt:
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or a
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jr z,bank0
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neg ; 2 -> -2
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add a,8Dh ; 8Dh - 2 = 8Bh
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@hbbio equ $ - 1 ; BID_BIOS
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ret
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bank0:
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ld a,8Eh ; 0 -> 8Eh
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@hbusr equ $ - 1 ; BID_USR
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ret
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movtyp db 0 ; non-zero for interbank move
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movbnks:
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srcbnk db 0
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dstbnk db 0
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end
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