Attached input handling and timer decrements.

src/machine/cpu.odin

@@ -5,6 +5,7 @@ import "core:math/rand"
 import "base:intrinsics"
 
 // CPU.odin -> instructions, fetch, decode, execute, run loop
+// ----------------------------------------------------------
 
 cycle :: proc(s: ^System) {
 	// Fetch
@@ -273,20 +274,20 @@ op_ld_dt :: proc(s: ^System, vx_idx: u16) {
 
 // Fx0A - LD Vx, K
 op_get_key :: proc(s: ^System, vx_idx: u16) {
-	for val, kp_idx in s.keypad {
+	if s.current_key != -1 {
-		if val == true {
+		key := s.current_key
-			s.v[vx_idx] = u8(kp_idx)
 
-			// return here so it does not decrement
+		released := check_if_key_released(key)
+		if released {
+			s.v[vx_idx] = u8(key)
+			s.current_key = -1
 			return
 		}
 	}
 
-	// if loop does not return decrement go into loop
 	s.pc -= 2
 }
 
-
 // Fx15 - LD DT, Vx
 op_set_dt :: proc(s: ^System, vx_idx: u16) {
 	// set delay timer to value of x register
@@ -333,3 +334,4 @@ op_mem_get :: proc(s: ^System, vx_idx: u16) {
 		s.v[loop_idx] = s.memory[s.i + loop_idx]
 	}
 }
+

src/machine/display.odin

@@ -23,8 +23,11 @@ run_system :: proc(s: ^System) {
 		// Do a cpu cycle
 		// Cap at 60hz/60fps
 		for _ in 0..<CYCLES_PER_FRAME {
+			handle_input(s)
 			cycle(s)
 		}
+		if s.delay_timer > 0 { s.delay_timer -= 1 }
+		if s.sound_timer > 0 { s.sound_timer -= 1 }
 
 		render_display_buffer(&s.display)
 
@@ -34,6 +37,7 @@ run_system :: proc(s: ^System) {
 	rl.CloseWindow()
 }
 
+
 // update display with display buffer bits
 render_display_buffer :: proc(display_buffer: ^[32][64]u8) {
 	// get row

src/machine/input.odin

@@ -1,3 +1,89 @@
 package machine
 
-// keypad mapping, input state update
+import rl "vendor:raylib"
+
+// @IDEA: Maybe add controller support?
+
+// Input handling for CHIP-8 keypad (0x0-0xF) mapped to a standard keyboard.
+// CHIP-8 uses a polling model, not hardware interrupts - we check key state each cycle.
+// Standard CHIP-8 -> keyboard mapping:
+// 1 2 3 C      →    1 2 3 4
+// 4 5 6 D      →    Q W E R
+// 7 8 9 E      →    A S D F
+// A 0 B F      →    Z X C V
+
+handle_input :: proc(s: ^System) {
+	// Row 1
+	s.keypad[0x1] = rl.IsKeyDown(.ONE)
+	s.keypad[0x2] = rl.IsKeyDown(.TWO)
+	s.keypad[0x3] = rl.IsKeyDown(.THREE)
+	s.keypad[0xC] = rl.IsKeyDown(.FOUR)
+	// Row 2
+	s.keypad[0x4] = rl.IsKeyDown(.Q)
+	s.keypad[0x5] = rl.IsKeyDown(.W)
+	s.keypad[0x6] = rl.IsKeyDown(.E)
+	s.keypad[0xD] = rl.IsKeyDown(.R)
+	// Row 3
+	s.keypad[0x7] = rl.IsKeyDown(.A)
+	s.keypad[0x8] = rl.IsKeyDown(.S)
+	s.keypad[0x9] = rl.IsKeyDown(.D)
+	s.keypad[0xE] = rl.IsKeyDown(.F)
+	// Row 4
+	s.keypad[0xA] = rl.IsKeyDown(.Z)
+	s.keypad[0x0] = rl.IsKeyDown(.X)
+	s.keypad[0xB] = rl.IsKeyDown(.C)
+	s.keypad[0xF] = rl.IsKeyDown(.V)
+
+	// Track the last pressed key as a CHIP-8 index (0x0-0xF).
+	// Used by Fx0A which blocks until a key is pressed AND released.
+	// current_key holds the index until release is confirmed, then resets to -1.
+	key := rl.GetKeyPressed()
+
+	#partial switch key {
+		case .ONE:   s.current_key = 0x1
+		case .TWO:   s.current_key = 0x2
+		case .THREE: s.current_key = 0x3
+		case .FOUR:  s.current_key = 0xC
+		case .Q:     s.current_key = 0x4
+		case .W:     s.current_key = 0x5
+		case .E:     s.current_key = 0x6
+		case .R:     s.current_key = 0xD
+		case .A:     s.current_key = 0x7
+		case .S:     s.current_key = 0x8
+		case .D:     s.current_key = 0x9
+		case .F:     s.current_key = 0xE
+		case .Z:     s.current_key = 0xA
+		case .X:     s.current_key = 0x0
+		case .C:     s.current_key = 0xB
+		case .V:     s.current_key = 0xF
+	}
+}
+
+// Returns true only when the tracked key is released.
+// Used by Fx0A to check for a press-and-release.
+check_if_key_released :: proc(key: i16) -> bool {
+	return rl.IsKeyReleased(chip8_key_to_raylib(key))
+}
+
+// Maps a CHIP-8 key index (0x0-0xF) back to its Raylib equivalent.
+chip8_key_to_raylib :: proc(key: i16) -> rl.KeyboardKey {
+	switch key {
+		case 0x1: return .ONE
+		case 0x2: return .TWO
+		case 0x3: return .THREE
+		case 0xC: return .FOUR
+		case 0x4: return .Q
+		case 0x5: return .W
+		case 0x6: return .E
+		case 0xD: return .R
+		case 0x7: return .A
+		case 0x8: return .S
+		case 0x9: return .D
+		case 0xE: return .F
+		case 0xA: return .Z
+		case 0x0: return .X
+		case 0xB: return .C
+		case 0xF: return .V
+		case: return .KEY_NULL
+	}
+}

src/machine/machine.odin

@@ -19,7 +19,11 @@ System :: struct {
 	pc: u16,
 	// 64x32-pixel monochrome display
 	display: [32][64]u8,
+	// Keypad
 	keypad: [16]bool,
+	// -1 = no key pressed, 0-15 = key index
+	current_key: i16,
+	// Timers
 	delay_timer: u8,
 	sound_timer: u8,
 }

src/main.odin

@@ -25,7 +25,8 @@ main :: proc() {
 	// load rom, hardcoded for now, will eventually be cli or gui
 	// err := chip.load_rom(&system, "./test_roms/2-ibm-logo.ch8")
 	// err := chip.load_rom(&system, "./test_roms/1-chip8-logo.ch8")
-	err := chip.load_rom(&system, "./test_roms/4-flags.ch8")
+	// err := chip.load_rom(&system, "./test_roms/4-flags.ch8")
+	err := chip.load_rom(&system, "./test_roms/6-keypad.ch8")
 	if err != nil {
 		panic("failed to load rom!")
 	}