pause on the start button

Code/automata.asm

@@ -15,6 +15,7 @@ EXPORT Buffer1
 SECTION "Automata buffer 1", WRAM0, ALIGN[9]
 Buffer1: ds 20 * 18
 
+EXPORT Old
 SECTION "Automata data", HRAM
 New: ds 1 ; high byte of pointer to bufferX
 Old: ds 1 ; high byte of pointer to bufferX
@@ -261,6 +262,12 @@ UpdateAutomata:
 .bottomright
 	ConwayGroup -19, -359, -340, -341, -1, -21, -20, -39
 	
+	; move buffer address back to beginning
+	ld hl, Old
+	dec [hl]
+	xor a
+	ldh [Progress], a
+	
 	ret
 
 EXPORT SwapBuffers, InitAutomata

Code/edit.asm

@@ -0,0 +1,93 @@
+INCLUDE "hardware.inc"
+
+Section "Joypad memory", HRAM
+; Bits 0..7 are A, B, Select, Start, Right, Left, Up, Down
+JoypadDown: ds 1
+JoypadPressed: ds 1
+
+SECTION "Update joypad", ROM0
+UpdateJoypad:
+	; read directions
+	ld a, P1F_5
+	ldh [rP1], a 
+	ldh a, [rP1]
+	ldh a, [rP1]
+	ldh a, [rP1]
+	ldh a, [rP1]
+	and a, $0F
+	swap a ; move into high nibble
+	ld b, a
+	
+	; read buttons
+	ld a, P1F_4
+	ldh [rP1], a 
+	ldh a, [rP1]
+	ldh a, [rP1]
+	ldh a, [rP1]
+	ldh a, [rP1]
+	and a, $0F
+	
+	; merge directions and buttons
+	; complement so that active buttons read as 1
+	or a, b
+	cpl
+
+	; backup all buttons in B
+	ld b, a
+	
+	; store just pressed buttons
+	ldh a, [JoypadPressed]
+	cpl 
+	and a, b
+	ldh [JoypadDown], a
+	
+	; store currently pressed buttons
+	ld a, b
+	ldh [JoypadPressed], a
+	
+	; reset joypad
+	ld a, $30
+	ldh [rP1], a
+	ret
+
+Section "Edit memory", HRAM
+SelectX: ds 1
+SelectY: ds 1
+
+EXPORT InitEdit
+SECTION "Init edit", ROM0
+InitEdit:
+	ld a, 20
+	ldh [SelectX], a
+	ld a, 18
+	ldh [SelectY], a
+	xor a
+	ldh [JoypadDown], a
+	ldh [JoypadPressed], a
+	ret
+	
+
+EXPORT EditOldBuffer
+SECTION "Edit old buffer", ROM0
+EditOldBuffer:
+	call UpdateJoypad
+	
+	ldh a, [JoypadDown]
+	and a, %1000
+	ret z
+	
+.loop
+	halt
+	xor a
+	ldh a, [rIF]
+
+	call UpdateJoypad
+	ldh a, [JoypadDown]
+	and a, %1000
+	ret nz
+
+	jr .loop
+	
+	
+	
+	

Code/main.asm

@@ -69,6 +69,7 @@ Start:
 	call MemoryCopy
 	
 	call InitAutomata
+	call InitEdit
 	
 	; enable h-blank interrupt in lcd stat
 	ld a, STATF_MODE00
@@ -82,5 +83,6 @@ Start:
 	call StartRender
 	call UpdateAutomata
 	call WaitRender
+	call EditOldBuffer
 	call SwapBuffers
 	jp .mainloop

build.bat

@@ -4,5 +4,6 @@
 ..\..\Assembler\rgbasm -i ..\..\Include\ -i Graphics\ -i Code\ -o Build\render.o       Code\render.asm
 ..\..\Assembler\rgbasm -i ..\..\Include\ -i Graphics\ -i Code\ -o Build\utils.o        Code\utils.asm
 ..\..\Assembler\rgbasm -i ..\..\Include\ -i Graphics\ -i Code\ -o Build\nintendo-out.o Code\nintendo-out.asm
-..\..\Assembler\rgblink -n rom.sym -w -t -o rom.gb -d Build/main.o Build/data.o Build/automata.o Build/render.o Build/utils.o Build/nintendo-out.o
+..\..\Assembler\rgbasm -i ..\..\Include\ -i Graphics\ -i Code\ -o Build\edit.o Code\edit.asm
+..\..\Assembler\rgblink -n rom.sym -w -t -o rom.gb -d Build/main.o Build/data.o Build/automata.o Build/render.o Build/utils.o Build/nintendo-out.o Build/edit.o
 ..\..\Assembler\rgbfix -t "Game of Life" -v -p 0 rom.gb