Fix ld a, []

[fpgaboy.git] / diag.asm

diff --git a/diag.asm b/diag.asm
index 8e09874baaf06cdb9b6472508f81a2cbff6a8dda..2c843eb33c7a1a0a15a4349f3ffe66ebf9f8b46c 100644 (file)
--- a/diag.asm
+++ b/diag.asm
@@ -32,6 +32,8 @@ main:
        
        ld hl, signon
        call puts
+
+       call putscreen
        
        ei
 
@@ -48,6 +50,67 @@ main:
 signon:
        db $0D,$0A,$1B,"[1mFPGABoy Diagnostic ROM",$1B,"[0m",$0D,$0A,0
 
+putscreen:
+       ; Wait for vblank
+.stat: ld a, [$FF41]
+       ld [$FF51], a
+       and $03         ; mode
+       cp $01          ; VBLANK
+       jr nz, .stat
+
+       ld hl, $8000    ; Copy two tiles.
+       ld a, $AA
+       ld [hli], a
+       ld [hli], a
+       ld a, $55
+       ld [hli], a
+       ld [hli], a
+       ld a, $AA
+       ld [hli], a
+       ld [hli], a
+       ld a, $55
+       ld [hli], a
+       ld [hli], a
+       ld a, $AA
+       ld [hli], a
+       ld [hli], a
+       ld a, $55
+       ld [hli], a
+       ld [hli], a
+       ld a, $AA
+       ld [hli], a
+       ld [hli], a
+       ld a, $55
+       ld [hli], a
+       ld [hli], a
+       xor a
+       ld [hli], a
+       ld [hli], a
+       ld [hli], a
+       ld [hli], a
+       ld [hli], a
+       ld [hli], a
+       ld [hli], a
+       ld [hli], a
+       ld [hli], a
+       ld [hli], a
+       ld [hli], a
+       ld [hli], a
+       ld [hli], a
+       ld [hli], a
+       ld [hli], a
+       ld [hli], a
+       
+       ld hl, $9800
+.loop: ld a, $01
+       ld [hli], a
+       xor a
+       ld [hli], a
+       ld a, h
+       cp $9C
+       jp nz,.loop
+       ret
+
 vbl:
        PUSH AF
        PUSH BC
@@ -61,6 +124,11 @@ vbl:
        ld a, [c]
        inc a
        ld [c], a
+       
+       ld c, $43       ; SCX
+       ld a, [c]
+       inc a
+       ld [c], a
 
        POP HL
        POP DE