Initial commit

scripts/Chip8.gd

@@ -0,0 +1,119 @@
+extends ColorRect
+
+var memory = []
+var registers = []
+var opcode = 0
+var index = 0
+var pc = 0
+var gfx = []
+var delay = 0
+var soundTimer = 0
+var stack = []
+var sp = 0
+var keys = []
+var isRedraw = true
+var canRun =  false
+var fontSet = [
+	0xF0, 0x90, 0x90, 0x90, 0xF0, # 0
+	0x20, 0x60, 0x20, 0x20, 0x70, # 1
+	0xF0, 0x10, 0xF0, 0x80, 0xF0, # 2
+	0xF0, 0x10, 0xF0, 0x10, 0xF0, # 3
+	0x90, 0x90, 0xF0, 0x10, 0x10, # 4
+	0xF0, 0x80, 0xF0, 0x10, 0xF0, # 5
+	0xF0, 0x80, 0xF0, 0x90, 0xF0, # 6
+	0xF0, 0x10, 0x20, 0x40, 0x40, # 7
+	0xF0, 0x90, 0xF0, 0x90, 0xF0, # 8
+	0xF0, 0x90, 0xF0, 0x10, 0xF0, # 9
+	0xF0, 0x90, 0xF0, 0x90, 0x90, # A
+	0xE0, 0x90, 0xE0, 0x90, 0xE0, # B
+	0xF0, 0x80, 0x80, 0x80, 0xF0, # C
+	0xE0, 0x90, 0x90, 0x90, 0xE0, # D
+	0xF0, 0x80, 0xF0, 0x80, 0xF0, # E
+	0xF0, 0x80, 0xF0, 0x80, 0x80  # F
+]
+
+export var displayWidth = 64
+export var displayHeight = 32
+
+export var memSize = 4096
+export var numRegisters = 16
+var displaySize = (displayWidth * displayHeight)
+export var stackLevels = 16
+export var keyboardBtns = 16
+
+func initSystem():
+	
+	memory = []
+	for i in range(memSize):
+		memory.append(0)
+	
+	registers = []
+	for i in range(numRegisters):
+		registers.append(0)
+	
+	gfx = []
+	for i in range(displaySize):
+		gfx.append(0)
+	
+	stack = []
+	for i in range(stackLevels):
+		stack.append(0)
+		
+	keys = []
+	for i in range(keyboardBtns):
+		keys.append(0)
+	
+	opcode = 0
+	pc = 0x200
+	index = 0
+	sp = 0
+	isRedraw = true
+	
+	for i in range(fontSet.size()):
+		memory[0x50 + i] = fontSet[i] & 0xFF
+	
+	
+func runSystem():
+	var jump = false
+	
+	opcode = (memory[pc] << 8) | memory[pc + 1]
+	
+	# Instructions
+	match (opcode & 0xF000):
+		0x0000:
+			match (opcode & 0x0FFF):
+				0x00E0: # CLS
+					for i in range(gfx.size()):
+						gfx[i] = 0
+					
+					isRedraw = true
+				0x00EE: # RET
+					sp -= 1
+					pc = stack[sp] + 2
+					jump = true
+					
+				_:
+					var addr = opcode & 0x0FFF
+					pc = addr
+					jump = true
+					
+	if (jump == false):
+		pc += 2
+		
+	if (delay > 0):
+		delay -= 1
+	
+	if (soundTimer > 0):
+		if (soundTimer == 1):
+			$AudioStreamPlayer.play()
+		
+		soundTimer -= 1
+
+# Called when the node enters the scene tree for the first time.
+func _ready():
+	pass # Replace with function body.
+
+
+# Called every frame. 'delta' is the elapsed time since the previous frame.
+#func _process(delta):
+#	pass