collapseos/kernel/blockdev_cmds.asm
Virgil Dupras 63473cc2e3 blockdev: make selection structure opaque
I'm about to change that structure and I don't want fs to be messed up
by this. I'm proceeding step by step...
2019-06-04 09:56:36 -04:00

110 lines
1.9 KiB
NASM

; *** REQUIREMENTS ***
; blockdev
; stdio
blkBselCmd:
.db "bsel", 0b001, 0, 0
ld a, (hl) ; argument supplied
cp BLOCKDEV_COUNT
jr nc, .error ; if selection >= device count, error
push de
ld de, BLOCKDEV_SEL
call blkSel
pop de
xor a
ret
.error:
ld a, BLOCKDEV_ERR_OUT_OF_BOUNDS
ret
blkSeekCmd:
.db "seek", 0b001, 0b011, 0b001
; First, the mode
ld a, (hl)
inc hl
push af ; save mode for later
; HL points to two bytes that contain out address. Seek expects HL
; to directly contain that address.
ld a, (hl)
ex af, af'
inc hl
ld a, (hl)
ld l, a
ex af, af'
ld h, a
pop af ; bring mode back
ld de, 0 ; DE is used for seek > 64K which we don't support
call blkSeek
call blkTell
ld a, h
call printHex
ld a, l
call printHex
call printcrlf
xor a
ret
; Load the specified number of bytes (max 0xff) from IO and write them in the
; current memory pointer (which doesn't change). If the 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
; call to GetC failed)
;
; Example: load 42
blkLoadCmd:
.db "load", 0b001, 0, 0
blkLoad:
push bc
push hl
ld a, (hl)
ld b, a
ld hl, (SHELL_MEM_PTR)
call blkGetC
jr nz, .ioError
.loop:
ld (hl), a
inc hl
call blkGetC
jr nz, .loopend
djnz .loop
.loopend:
; success
xor a
jr .end
.ioError:
ld a, SHELL_ERR_IO_ERROR
.end:
pop hl
pop bc
ret
; Load the specified number of bytes (max 0xff) from the current memory pointer
; and write them to I/O. Memory pointer doesn't move. This puts chars to
; blkPutC.
; Control is returned to the shell only after all bytes are written.
;
; Example: save 42
blkSaveCmd:
.db "save", 0b001, 0, 0
blkSave:
push bc
push hl
ld a, (hl)
ld b, a
ld hl, (SHELL_MEM_PTR)
.loop:
ld a, (hl)
inc hl
call blkPutC
djnz .loop
.end:
pop hl
pop bc
xor a
ret