dpad invert support

2018-03-13 00:16:23 -04:00
parent d2576c9433
commit 365cb58f01
4 changed files with 28 additions and 0 deletions
--- a/dpadinvert.asm
+++ b/dpadinvert.asm
@@ -0,0 +1,18 @@
+;================================================================================
+; D-Pad Invert
+; runs in NMI, must use minimum possible # of cycles
+;--------------------------------------------------------------------------------
+; Filtered Joypad 1 Register: [BYST | udlr].
+!INVERT_DPAD = "$7F50CB"
+InvertDPad:
+	LDA !INVERT_DPAD : BEQ .normal
+	.inverted
+	LDA $4219 
+		BIT.b #$0C : BEQ + : EOR #$0C : +
+		BIT.b #$03 : BEQ + : EOR #$03 : +
+	STA $01
+RTL
+	.normal
+	LDA $4219 : STA $01
+RTL
+;--------------------------------------------------------------------------------