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118 lines
2.0 KiB
NASM
118 lines
2.0 KiB
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_SEL
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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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ld de, 0 ; DE is used for seek > 64K which we don't support
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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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; Load the specified number of bytes (max 0x100, 0 means 0x100) from IO and
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; write them in the current memory pointer (which doesn't change). If the
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; blkdev hits end of stream before we reach our specified number of bytes, we
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; stop loading.
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;
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; Returns a SHELL_ERR_IO_ERROR only if we couldn't read any byte (if the first
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; call to GetC failed)
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;
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; Example: load 42
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blkLoadCmd:
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.db "load", 0b001, 0, 0
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blkLoad:
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push bc
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push hl
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ld a, (hl)
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ld b, a
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ld hl, (SHELL_MEM_PTR)
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call blkGetC
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jr nz, .ioError
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jr .intoLoop ; we'v already called blkGetC. don't call it
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; again.
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.loop:
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call blkGetC
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.intoLoop:
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ld (hl), a
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inc hl
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jr nz, .loopend
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djnz .loop
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.loopend:
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; success
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xor a
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jr .end
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.ioError:
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ld a, SHELL_ERR_IO_ERROR
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.end:
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pop hl
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pop bc
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ret
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; Load the specified number of bytes (max 0x100, 0 means 0x100) from the current
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; memory pointer and write them to I/O. Memory pointer doesn't move. This puts
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; chars to blkPutC. Raises error if not all bytes could be written.
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;
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; Example: save 42
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blkSaveCmd:
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.db "save", 0b001, 0, 0
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blkSave:
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push bc
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push hl
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ld a, (hl)
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ld b, a
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ld hl, (SHELL_MEM_PTR)
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.loop:
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ld a, (hl)
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inc hl
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call blkPutC
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jr nz, .ioError
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djnz .loop
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.loopend:
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; success
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xor a
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jr .end
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.ioError:
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ld a, SHELL_ERR_IO_ERROR
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.end:
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pop hl
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pop bc
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ret
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