diff options
Diffstat (limited to 'src/blk.asm')
| -rw-r--r-- | src/blk.asm | 65 |
1 files changed, 12 insertions, 53 deletions
diff --git a/src/blk.asm b/src/blk.asm index ea04e95..2be961e 100644 --- a/src/blk.asm +++ b/src/blk.asm @@ -83,57 +83,6 @@ write_block:: restore_bank ret -; ----------------------------------------------------------------------------- -; blk_format - write a fresh superblock (magic) to block 0. (mkfs, stage 1) -; ----------------------------------------------------------------------------- -blk_format:: - ld hl, wCopyBuf ; zero the buffer - ld b, 0 - xor a -.z - ld [hl+], a - dec b - jr nz, .z - ld hl, wCopyBuf - ld a, SUPER_MAG0 - ld [hl+], a - ld a, SUPER_MAG1 - ld [hl+], a - ld a, SUPER_MAG2 - ld [hl+], a - ld a, SUPER_MAG3 - ld [hl], a - ld a, SUPER_BLOCK - ld hl, wCopyBuf - call write_block - ret - -; ----------------------------------------------------------------------------- -; blk_init - format the disk only if it isn't already formatted (magic check). -; Called at boot; the disk otherwise persists across power cycles (.sav). -; ----------------------------------------------------------------------------- -blk_init:: - ld a, SUPER_BLOCK - ld hl, wCopyBuf - call read_block - ld hl, wCopyBuf - ld a, [hl+] - cp SUPER_MAG0 - jr nz, .fmt - ld a, [hl+] - cp SUPER_MAG1 - jr nz, .fmt - ld a, [hl+] - cp SUPER_MAG2 - jr nz, .fmt - ld a, [hl] - cp SUPER_MAG3 - jr nz, .fmt - ret ; already formatted -.fmt - call blk_format - ret - ; ============================================================================= ; [debug] block poke/peek syscalls, to validate the layer + persistence. ; ============================================================================= @@ -152,10 +101,20 @@ sys_bfill:: xor a ret -; sys_bpeek(B = block) -> A = block's first byte +; sys_bpeek(B = block, E = offset) -> A = block[offset] sys_bpeek:: + ld a, e + ld [wFsByte], a ; stash offset ld a, b ld hl, wCopyBuf call read_block - ld a, [wCopyBuf] + ld hl, wCopyBuf + ld a, [wFsByte] + add l + ld l, a + ld a, h + adc 0 + ld h, a + ld a, [hl] ret + |