1 files changed, 39 insertions, 0 deletions
diff --git a/home/joypad.asm b/home/joypad.asm
new file mode 100644
index 00000000..2002bb29
--- /dev/null
+++ b/home/joypad.asm
@@ -0,0 +1,39 @@
+ReadJoypad::
+; 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::
+; Update the joypad state variables:
+; [hJoyReleased]  keys released since last time
+; [hJoyPressed]   keys pressed since last time
+; [hJoyHeld] currently pressed keys
+	homecall _Joypad
+	ret