Update joypad.asm

1 files changed, 36 insertions, 1 deletions

diff --git a/engine/joypad.asm b/engine/joypad.asm
index 31e197e2..791056ca 100644
--- a/engine/joypad.asm
+++ b/engine/joypad.asm
@@ -1,8 +1,43 @@
-_Joypad::
+ReadJoypad_:: ; c000 (3:4000)
+; Poll joypad input.
+; Unlike the hardware register, button
+; presses are indicated by a set bit.
+
+	ld a, 1 << 5 ; select direction keys
+	ld c, 0
+
+	ld [rJOYP], a
+	rept 6
+	ld a, [rJOYP]
+	endr
+	cpl
+	and %1111
+	swap a
+	ld b, a
+
+	ld a, 1 << 4 ; select button keys
+	ld [rJOYP], a
+	rept 10
+	ld a, [rJOYP]
+	endr
+	cpl
+	and %1111
+	or b
+
+	ld [hJoyInput], a
+
+	ld a, 1 << 4 + 1 << 5 ; deselect keys
+	ld [rJOYP], a
+	ret
+
+
+_Joypad:: ; c02d (3:402d)
 ; hJoyReleased: (hJoyLast ^ hJoyInput) & hJoyLast
 ; hJoyPressed:  (hJoyLast ^ hJoyInput) & hJoyInput
 
 	ld a, [hJoyInput]
+	ld b,a
+	and $4F
 	cp A_BUTTON + B_BUTTON + SELECT + START ; soft reset
 	jp z, TrySoftReset