X-Git-Url: http://git.joshuawise.com/fpgaboy.git/blobdiff_plain/14778cde2df07491e9c2e8da0e8a1ab8724e6cec..c279b66691509cfc4445a568dab29a3282f03f3f:/diag.asm

diff --git a/diag.asm b/diag.asm
index e7bb0d4..e9fff6a 100644
--- a/diag.asm
+++ b/diag.asm
@@ -94,12 +94,8 @@ putscreen:
 	ld hl, $8000	; Copy two tiles.
 	ld de, tiles
 	ld c, $20
-.cloop:	push hl
-	ld h, d
-	ld l, e
-	ld a, [hl]
+.cloop:	ld a, [de]
 	inc de
-	pop hl
 	ld [hli], a
 	ld [hli], a
 	dec c
@@ -145,30 +141,19 @@ vbl:
 	ld [$FF0F], a
 
 	ld a, [$FF51]
-	ld b, a
-	and $80
-	cp $80
-	jr nz, .nothing
-	ld c, $0
+	bit 7, a
+	jr z, .nothing
 
-	ld a, b
-	and $1
-	cp c
+	bit 0, a
 	call nz, .scyup
 	
-	ld a, b
-	and $2
-	cp c
+	bit 1, a
 	call nz, .scydown
 	
-	ld a, b
-	and $4
-	cp c
+	bit 2, a
 	call nz, .scxup
 	
-	ld a, b
-	and $8
-	cp c
+	bit 3, a
 	call nz, .scxdown
 
 .nothing: