mirror of https://github.com/hsoft/collapseos.git
60 lines
1.0 KiB
NASM
60 lines
1.0 KiB
NASM
; vid - TRS-80's video
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;
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; Implement PutC and GRID_SETCELL using TRS-80's SVC calls.
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.equ TRS80_COLS 80
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.equ TRS80_ROWS 24
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trs80PutC:
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push af
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push bc
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push de ; altered by SVC
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ld c, a
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ld a, 0x02 ; @DSP
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rst 0x28
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pop de
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pop bc
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pop af
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ret
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trs80SetCell:
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push af
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push bc
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push hl ; HL altered by @VDCTL
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push de ; DE altered by @VDCTL
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ex de, hl
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bit 0, c
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ld c, a ; save A now
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jr z, .skip ; Z from BIT above. cursor not set
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; set cursor
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ld a, 0x0f ; @VDCTL
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ld b, 3 ; move cursor fn
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rst 0x28
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; HL altered.
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; Our Row/Col is our currently-pushed DE value. Let's take advantage of
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; that.
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pop hl \ push hl ; HL altered. bring back from stack
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.skip:
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ld a, 0x0f ; @VDCTL
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ld b, 2 ; display char
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rst 0x28
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pop de
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pop hl
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pop bc
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pop af
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ret
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; This is a much faster version of gridPushScr. Use it in your glue code, but
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; you need to set HL to GRID_BUF first.
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trs80PushScr:
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push af
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push bc
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ld a, 0x0f ; @VDCTL
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ld b, 5 ; move from RAM to vid
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; HL is already set by caller
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rst 0x28
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pop bc
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pop af
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cp a ; ensure Z
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ret
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