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blockdev: fix load command over-loading a byte 

Calling `load` would always read one more byte than specified. Also,
make `0` mean `0x100`.
This commit is contained in:
Virgil Dupras 2019-06-17 08:19:03 -04:00
parent bd2877e012
commit 8cf9904f33
1 changed files with 9 additions and 6 deletions
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15
kernel/blockdev_cmds.asm
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@ -44,9 +44,10 @@ blkSeekCmd:
xor a xor a
ret ret
; Load the specified number of bytes (max 0xff) from IO and write them in the ; Load the specified number of bytes (max 0x100, 0 means 0x100) from IO and
; current memory pointer (which doesn't change). If the blkdev hits end of ; write them in the current memory pointer (which doesn't change). If the
; stream before we reach our specified number of bytes, we stop loading. ; blkdev hits end of stream before we reach our specified number of bytes, we
; stop loading.
; ;
; Returns a SHELL_ERR_IO_ERROR only if we couldn't read any byte (if the first ; Returns a SHELL_ERR_IO_ERROR only if we couldn't read any byte (if the first
; call to GetC failed) ; call to GetC failed)
@ -63,11 +64,13 @@ blkLoad:
ld hl, (SHELL_MEM_PTR) ld hl, (SHELL_MEM_PTR)
call blkGetC call blkGetC
jr nz, .ioError jr nz, .ioError
jr .intoLoop ; properly dec B + check on first iteration.
.loop: .loop:
ld (hl), a ld (hl), a
inc hl inc hl
call blkGetC call blkGetC
jr nz, .loopend jr nz, .loopend
.intoLoop:
djnz .loop djnz .loop
.loopend: .loopend:
; success ; success
@ -80,9 +83,9 @@ blkLoad:
pop bc pop bc
ret ret
; Load the specified number of bytes (max 0xff) from the current memory pointer ; Load the specified number of bytes (max 0x100, 0 means 0x100) from the current
; and write them to I/O. Memory pointer doesn't move. This puts chars to ; memory pointer and write them to I/O. Memory pointer doesn't move. This puts
; blkPutC. Raises error if not all bytes could be written. ; chars to blkPutC. Raises error if not all bytes could be written.
; ;
; Example: save 42 ; Example: save 42
blkSaveCmd: blkSaveCmd: