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collapseos/apps/sdct/main.asm
Virgil Dupras 92a04f4627 sdc: support 24-bit addressing
Needed if we want to compile the kernel and zasm from within a SD card.
I didn't go straight for 32-bit because it was significantly more
complex and 24-bit give us 16M. Enough to go on for a while...
2019-06-15 13:41:20 -04:00

73 lines
1.2 KiB
NASM

sdctMain:
ld hl, .sWriting
call printstr
ld hl, 0
ld de, SDCT_RAMSTART
.wLoop:
ld a, (de)
; To avoid overwriting important data and to test the 24-bit addressing,
; we set DE to 12 instead of zero
push de ; <|
ld de, 12 ; |
call sdcPutC ; |
pop de ; <|
jr nz, .error
inc hl
inc de
; Stop looping if DE == 0
xor a
cp e
jr nz, .wLoop
; print some kind of progress
call printHexPair
cp d
jr nz, .wLoop
; Finished writing
ld hl, .sReading
call printstr
ld hl, 0
ld de, SDCT_RAMSTART
.rLoop:
push de ; <|
ld de, 12 ; |
call sdcGetC ; |
pop de ; <|
jr nz, .error
ex de, hl
cp (hl)
ex de, hl
jr nz, .notMatching
inc hl
inc de
; Stop looping if DE == 0
xor a
cp d
jr nz, .rLoop
cp e
jr nz, .rLoop
; Finished checking
xor a
ld hl, .sOk
jp printstr ; returns
.notMatching:
; error position is in HL, let's preserve it
ex de, hl
ld hl, .sNotMatching
call printstr
ex de, hl
jp printHexPair ; returns
.error:
ld hl, .sErr
jp printstr ; returns
.sWriting:
.db "Writing", 0xd, 0xa, 0
.sReading:
.db "Reading", 0xd, 0xa, 0
.sNotMatching:
.db "Not matching at pos ", 0xd, 0xa, 0
.sErr:
.db "Error", 0xd, 0xa, 0
.sOk:
.db "OK", 0xd, 0xa, 0