Make it easy to see what's going wrong.

[fpgaboy.git] / diag.asm

diff --git a/diag.asm b/diag.asm
index 7f06de0ce42223f19f4dc2b67a74a5497592e8c8..77c520264a6715e5e1758a334eb0b8b68f0af90b 100644 (file)
--- a/diag.asm
+++ b/diag.asm
@@ -50,23 +50,71 @@ main:
 signon:
        db $0D,$0A,$1B,"[1mFPGABoy Diagnostic ROM",$1B,"[0m",$0D,$0A,0
 
+tiles:
+       db %11111111
+       db %11111111
+       db %11000011
+       db %11000011
+       db %11000011
+       db %11000011
+       db %11111111
+       db %11111111
+       
+       db %00000000
+       db %00000000
+       db %00000000
+       db %00000000
+       db %00000000
+       db %00000000
+       db %00000000
+       db %00000000
+
 putscreen:
-       ld a, $FF               ; Copy two tiles.
-       ld hl, $8000
+       ; Wait for vblank
+       call .vblwait
+
+       ld hl, $8000    ; Copy two tiles.
+       ld de, tiles
+       ld c, $10
+.cloop:        push hl
+       ld h, d
+       ld l, e
+       ld a, [hl]
+       inc de
+       pop hl
        ld [hli], a
        ld [hli], a
+       dec c
        xor a
-       ld [hli], a
-       ld [hli], a
+       cp c
+       jr nz, .cloop
        
        ld hl, $9800
-.loop: ld a, $FF
-       ld [hli], a
-       xor a
+.vloop:        call .vblwait
+       ld c, $40
+       ld b, 0
+.loop: inc b
+       ld a, b
+       and $01
        ld [hli], a
        ld a, h
        cp $9C
-       jp nz,.loop
+       ret z
+       dec c
+       xor a
+       cp c
+       jr nz,.loop
+       jr .vloop
+
+.vblwait:
+.stat1:        ld a, [$FF41]   ; STAT
+       and $03
+       cp $00
+       jp nz, .stat1
+.stat2:        ld a, [$FF41]
+       and $03
+       cp $01
+       jr nz, .stat2
        ret
 
 vbl:
@@ -78,11 +126,34 @@ vbl:
        xor a
        ld [$FF0F], a
 
-       ld c, $42       ; SCY
-       ld a, [c]
-       inc a
-       ld [c], a
+       ld a, [$FF51]
+       ld b, a
+       and $80
+       cp $80
+       jr nz, .nothing
+       ld c, $0
 
+       ld a, b
+       and $1
+       cp c
+       call nz, .scyup
+       
+       ld a, b
+       and $2
+       cp c
+       call nz, .scydown
+       
+       ld a, b
+       and $4
+       cp c
+       call nz, .scxup
+       
+       ld a, b
+       and $8
+       cp c
+       call nz, .scxdown
+
+.nothing:
        POP HL
        POP DE
        POP BC
@@ -90,6 +161,23 @@ vbl:
 
        RETI
 
+.scyup:        ld hl, $FF42
+       inc [hl]
+       ret
+
+.scydown:      ld hl, $FF42
+       dec [hl]
+       ret
+
+.scxup:        ld hl, $FF43
+       inc [hl]
+       ret
+
+.scxdown:      ld hl, $FF43
+       dec [hl]
+       ret     
+       
+
 lcdc:
        PUSH AF
        PUSH BC