Code optimizations (by Stefan Haubenthal and me).

git-svn-id: svn://svn.cc65.org/cc65/trunk@3906 b7a2c559-68d2-44c3-8de9-860c34a00d81

libsrc/nes/nes-stdjoy.s

@@ -25,14 +25,14 @@
 
 ; Button state masks (8 values)
 
-	.byte	$08			; JOY_UP
-	.byte	$04			; JOY_DOWN
-	.byte	$02			; JOY_LEFT
-	.byte	$01			; JOY_RIGHT
-	.byte	$80			; JOY_FIRE  (A)
-	.byte	$40			; JOY_FIRE2 (B)
-	.byte	$20			; JOY_FIRE3 (Select)
-	.byte	$10			; JOY_FIRE4 (Start)
+        .byte	$10			; JOY_UP
+        .byte	$20			; JOY_DOWN
+        .byte	$40			; JOY_LEFT
+        .byte	$80			; JOY_RIGHT
+        .byte	$01			; JOY_FIRE	(A)
+        .byte	$02			; JOY_FIRE2	(B)
+        .byte	$04			; 		(Select)
+        .byte	$08			; 		(Start)
 
 ; Jump table.
 
@@ -88,25 +88,20 @@ READJOY:
         and	#$01		; Fix joystick number
         tay			; Joystick number (0,1) into Y
 
-; Read joystick
-
         lda	#1
         sta	APU_PAD1,y
         lda	#0
         sta	APU_PAD1,y
-	sta	tmp1
+
+; Read joystick
 
         ldx	#8
-@L1:	asl	tmp1
-	lda	APU_PAD1,y
-	and	#$01
-	beq	@L2
-	lda	tmp1
-	ora	#$01
-	sta	tmp1
-@L2:	dex
-	bne	@L1
+@Loop:  lda	APU_PAD1,y
+        ror	a
+        ror	tmp1
+        dex
+        bne	@Loop
 
         lda	tmp1
-;	ldx	#$00		; fix X
+;       ldx	#$00		; X implicitly fixed
         rts