34ee91a0d7
This will soon allow use to seek and tell on input, which is necessary for a second pass which is necessary for forward symbol references. This require making `blkSel` a bit more flexible. Rather than having one global selected blkdev, each app can select its own, in its own memory space.
46 lines
721 B
NASM
46 lines
721 B
NASM
; *** REQUIREMENTS ***
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; blockdev
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; stdio
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blkBselCmd:
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.db "bsel", 0b001, 0, 0
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ld a, (hl) ; argument supplied
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cp BLOCKDEV_COUNT
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jr nc, .error ; if selection >= device count, error
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push de
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ld de, BLOCKDEV_GETC
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call blkSel
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pop de
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xor a
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ret
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.error:
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ld a, BLOCKDEV_ERR_OUT_OF_BOUNDS
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ret
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blkSeekCmd:
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.db "seek", 0b001, 0b011, 0b001
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; First, the mode
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ld a, (hl)
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inc hl
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push af ; save mode for later
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; HL points to two bytes that contain out address. Seek expects HL
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; to directly contain that address.
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ld a, (hl)
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ex af, af'
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inc hl
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ld a, (hl)
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ld l, a
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ex af, af'
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ld h, a
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pop af ; bring mode back
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call blkSeek
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call blkTell
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ld a, h
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call printHex
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ld a, l
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call printHex
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call printcrlf
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xor a
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ret
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