Remove input.asm from title screen and put it in main, update build

Author: Les-Wet

unbricked/title-screen/build.sh

@@ -1,6 +1,5 @@
 #!/bin/sh
 
 rgbasm -o main.o main.asm
-rgbasm -o input.o input.asm
-rgblink -o unbricked.gb main.o input.o
+rgblink -o unbricked.gb main.o
 rgbfix -v -p 0xFF unbricked.gb

unbricked/title-screen/input.asm

@@ -115,6 +115,44 @@ Memcopy:
 	ret
 ; ANCHOR_END: memcpy
 
+; ANCHOR: input-routine
+UpdateKeys:
+    ; Poll half the controller
+    ld a, JOYP_GET_BUTTONS
+	call .onenibble
+	ld b, a ; B7-4 = 1; B3-0 = unpressed buttons
+
+	; Poll the other half
+	ld a, JOYP_GET_CTRL_PAD
+	call .onenibble
+	swap a ; A7-4 = unpressed directions; A3-0 = 1
+	xor a, b ; A = pressed buttons + directions
+	ld b, a ; B = pressed buttons + directions
+
+	; And release the controller
+	ld a, JOYP_GET_NONE
+	ldh [rJOYP], a
+
+	; Combine with previous wCurKeys to make wNewKeys
+	ld a, [wCurKeys]
+	xor a, b ; A = keys that changed state
+	and a, b ; A = keys that changed to pressed
+	ld [wNewKeys], a
+	ld a, b
+	ld [wCurKeys], a
+	ret
+
+	.onenibble
+	ldh [rJOYP], a ; switch the key matrix
+	call .knownret ; burn 10 cycles calling a known ret
+	ldh a, [rJOYP] ; ignore value while waiting for the key matrix to settle
+	ldh a, [rJOYP]
+	ldh a, [rJOYP] ; this read counts
+	or a, $F0 ; A7-4 = 1; A3-0 = unpressed keys
+	.knownret
+	ret
+; ANCHOR_END: input-routine
+
 Tiles:
 	dw `33333333
 	dw `33333333
@@ -337,3 +375,9 @@ Unbricked_Title_Screen_Map_Begin:
 	DB $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, 0,0,0,0,0,0,0,0,0,0,0,0
 	DB $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, 0,0,0,0,0,0,0,0,0,0,0,0
 Unbricked_Title_Screen_Map_End:
+
+; ANCHOR: vars
+SECTION "Input Variables", WRAM0
+wCurKeys: db
+wNewKeys: db
+; ANCHOR_END: vars