Chip-8 emulator

Complete Chip-8 instructions. However, the user still needs to modify the code to select the ROM. Next-step will be to insert SUPER-CHIP and OX-CHIP instructions, as well as to give menu options to the user.
This commit is contained in:
Marcus Vinicius de Carvalho 2021-07-22 19:39:56 +08:00
parent 9202042093
commit 26a1b85841
3 changed files with 541 additions and 91 deletions

1
.gitignore vendored
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@ -2,3 +2,4 @@
Cargo.lock
/src/SDL2.dll
/src/chip_8/roms

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@ -1,28 +1,42 @@
// CHIP-8 means Compact Hexadecimal Interpretive Programming - 8-bit
use ::sdl2;
use crate::chip_8::display;
use rand::Rng;
use std::io::Read;
const DISPLAY_WIDTH: usize = 64;
const DISPLAY_HEIGHT: usize = 32;
const DISPLAY_SCALE: u32 = 10;
pub struct ProgramCounter(usize);
pub struct Registers([u8; 16]);
pub struct Registers([u8; 0x10]);
pub struct Ram([u8; 4 * 1024]);
pub struct Timer(u8);
pub struct Timing(u16);
pub struct DisplayBuffer([[bool; DISPLAY_HEIGHT]; DISPLAY_WIDTH]);
pub struct Timer{
tick: u8,
clock_hz: u128,
elapsed: std::time::SystemTime
}
pub struct Keypad {
keys: [bool; 0xF],
layout: String
keys: [bool; 0x10],
// layout: String
}
pub struct OpCodes {
opcode: u16,
nible_1: u8,
nible_2: u8,
nible_3: u8,
nible_4: u8
}
impl ProgramCounter {
fn init() -> ProgramCounter {
ProgramCounter {
0: 0
0: 0x200
}
}
@ -30,6 +44,10 @@ impl ProgramCounter {
self.0 += 2;
}
fn decrement(&mut self) {
self.0 -= 2;
}
fn set(&mut self, value: usize) {
self.0 = value;
}
@ -47,18 +65,12 @@ impl Registers {
}
fn get(&self, register: usize) -> u8 {
if register <= 0xF {
self.0[register]
} else {
0
}
}
fn set(&mut self, register: usize, value: u8) {
if register <= 0xF {
self.0[register] = value;
}
}
}
impl Ram {
@ -69,7 +81,8 @@ impl Ram {
}
fn init_fonts(&mut self) {
const FONTS: [u8; 80] = [
let font_address = 0x50;
let fonts: [u8; 80] = [
0xF0, 0x90, 0x90, 0x90, 0xF0, // 0
0x20, 0x60, 0x20, 0x20, 0x70, // 1
0xF0, 0x10, 0xF0, 0x80, 0xF0, // 2
@ -86,8 +99,8 @@ impl Ram {
0xE0, 0x90, 0x90, 0x90, 0xE0, // D
0xF0, 0x80, 0xF0, 0x80, 0xF0, // E
0xF0, 0x80, 0xF0, 0x80, 0x80]; // F
for i in 0x50..0x80 {
self.0[i] = FONTS[i];
for i in 0..fonts.len() {
self.0[i + font_address] = fonts[i];
}
}
@ -99,70 +112,114 @@ impl Ram {
}
fn read8(&self, addr: usize) -> u8 {
assert!(addr <= self.0.len());
assert!(addr <= self.0.len(), "addr = {}, self.0.len() = {}", addr, self.0.len());
self.0[addr]
}
fn read16(&self, addr: usize) -> u16 {
assert!(addr < self.0.len());
// byteorder::LittleEndiar::read_u16(&self.ram[addr])
assert!(addr < self.0.len(), "addr = {}, self.0.len() = {}", addr, self.0.len());
// byteorder::LittleEndian::read_u16(&self.0[addr]);
// u16::from_le_bytes(self.ram[addr..addr+2])
// self.ram[addr..addr+2]
(self.0[addr] as u16) << 8 | self.0[addr+1] as u16
}
fn write8(&mut self, addr: usize, value: u8) {
assert!(addr < self.0.len());
self.0[addr] = value;
}
}
impl Timer {
fn init() -> Timer {
Timer {
0: 0
tick: 255,
clock_hz: 60,
elapsed: std::time::SystemTime::now()
}
}
fn tick(&mut self) -> bool {
self.0 -= 1;
self.0 == 0
let mut res: bool = false;
match self.elapsed.elapsed() {
Ok(elapsed) => {
if elapsed.as_secs_f32() >= 1./(self.clock_hz as f32) {
if self.tick > 0 { self.tick -= 1; }
self.reset_elapsed();
res = true;
}
}
Err(e) => {
println!("Error: {:?}", e);
}
}
res
}
fn reset_elapsed(&mut self) {
self.elapsed = std::time::SystemTime::now();
}
}
impl Keypad {
fn init() -> Keypad {
Keypad {
keys: [false; 0xF],
layout: String::from("123C456D789EA0BF")
keys: [false; 0x10],
// layout: String::from("123C456D789EA0BF")
}
}
fn set_layout(&mut self, layout: &str) {
assert_eq!(layout.len(), self.layout.len());
self.layout = layout.to_string();
}
}
fn compute_keycode(&self, keycode: sdl2::keyboard::Keycode) -> Option<usize> {
match keycode {
sdl2::keyboard::Keycode::Num1 => Some(0x1),
sdl2::keyboard::Keycode::Num2 => Some(0x2),
sdl2::keyboard::Keycode::Num3 => Some(0x3),
sdl2::keyboard::Keycode::Num4 => Some(0xC),
impl Timing {
fn init() -> Timing {
Timing {
0: 1000 // 1 MHz
sdl2::keyboard::Keycode::Q => Some(0x4),
sdl2::keyboard::Keycode::W => Some(0x5),
sdl2::keyboard::Keycode::E => Some(0x6),
sdl2::keyboard::Keycode::R => Some(0xD),
sdl2::keyboard::Keycode::A => Some(0x7),
sdl2::keyboard::Keycode::S => Some(0x8),
sdl2::keyboard::Keycode::D => Some(0x9),
sdl2::keyboard::Keycode::F => Some(0xE),
sdl2::keyboard::Keycode::Z => Some(0xA),
sdl2::keyboard::Keycode::X => Some(0x0),
sdl2::keyboard::Keycode::C => Some(0xB),
sdl2::keyboard::Keycode::V => Some(0xF),
_ => Option::None,
}
}
fn increase(&mut self) {
self.0 += 10;
// fn set_layout(&mut self, layout: &str) {
// assert_eq!(layout.len(), self.layout.len());
// self.layout = layout.to_string();
// }
fn get(&mut self, pos: usize) -> bool {
self.keys[pos]
}
fn decrease(&mut self) {
self.0 -= 10;
fn being_pressed(&self) -> u8 {
for key in 0x0..0x10 {
if self.keys[key] {
return key as u8
}
}
return 0x10
}
fn format(&self) -> String {
let mut res = String::new();
if self.0 >= 1000 {
res = format!("{:.2}{}", self.0/1000, "MHz");
} else {
res = format!("{}{}", self.0, "Hz");
fn press(&mut self, key: usize) {
self.keys[key] = true;
}
res
fn release(&mut self, key: usize) {
self.keys[key] = false;
}
}
@ -176,57 +233,455 @@ impl DisplayBuffer {
fn clear(&mut self) {
self.0 = [[false; DISPLAY_HEIGHT]; DISPLAY_WIDTH];
}
}
fn random(&mut self) {
for (x, col) in self.0.iter_mut().enumerate() {
for (y, pixel) in col.iter_mut().enumerate() {
let mut rng = rand::thread_rng();
*pixel = rng.gen_range(0..2) == 0;
impl OpCodes {
fn init(opcode: u16) -> OpCodes {
OpCodes {
opcode: opcode,
nible_1: ((opcode & 0xF000) >> 12) as u8,
nible_2: ((opcode & 0x0F00) >> 8) as u8,
nible_3: ((opcode & 0x00F0) >> 4) as u8,
nible_4: (opcode & 0x000F) as u8
}
}
fn get_x(&self) -> usize {
self.nible_2 as usize
}
fn get_y(&self) -> usize {
self.nible_3 as usize
}
fn get_nnn(&self) -> u16 {
self.opcode & 0xFFF
}
fn get_nn(&self) -> u8 {
(self.opcode & 0xFF) as u8
}
fn get_n(&self) -> u8 {
(self.opcode & 0xF) as u8
}
}
struct CPU {
pc: ProgramCounter,
index_register: usize,
stack: Vec<usize>,
delay_timer: Timer,
sound_timer: Timer,
clock: Timer,
registers: Registers,
ram: Ram,
keypad: Keypad,
display_buffer: DisplayBuffer
}
impl CPU {
fn init() -> CPU {
CPU {
pc: ProgramCounter::init(),
index_register: 0,
stack: vec![],
delay_timer: Timer::init(),
sound_timer: Timer::init(),
clock: Timer::init(),
registers: Registers::init(),
ram: Ram::init(),
keypad: Keypad::init(),
display_buffer: DisplayBuffer::init()
}
}
}
pub fn run() {
let mut pc = ProgramCounter::init();
let mut index_register: u16 = 0;
let mut stack: Vec<u16>;
let mut delay_timer = Timer::init();
let mut sound_timer = Timer::init();
let mut registers = Registers::init();
let mut ram = Ram::init();
let mut keypad = Keypad::init();
let mut timing = Timing::init();
let mut display_buffer = DisplayBuffer::init();
let mut cpu = CPU::init();
cpu.ram.init_fonts();
// load_rom("src/chip_8/roms/ibm_logo.ch8", &mut cpu);
load_rom("src/chip_8/roms/BC_test.ch8", &mut cpu);
// load_rom("src/chip_8/roms/test_opcode.ch8", &mut cpu);
// load_rom("src/chip_8/roms/HIDDEN.ch8", &mut cpu); // Good to test keyboard
// load_rom("src/chip_8/roms/CAVE.ch8", &mut cpu); // Good to test keyboard
// load_rom("src/chip_8/roms/TRON.ch8", &mut cpu); // Good to test keyboard
// load_rom("src/chip_8/roms/PUZZLE.ch8", &mut cpu); // Good to test keyboard?
// load_rom("src/chip_8/roms/TETRIS.ch8", &mut cpu); // Good to test keyboard?
// load_rom("src/chip_8/roms/delay_timer_test.ch8", &mut cpu);
// load_rom("src/chip_8/roms/random_number_test.ch8", &mut cpu);
let sdl_context = sdl2::init().unwrap();
let mut display = crate::chip_8::display::Display::init(&sdl_context, DISPLAY_SCALE);
let mut event_listener = sdl_context.event_pump().unwrap();
let mut is_running = true;
cpu.clock.clock_hz = 60;
'runner: loop {
for event in event_listener.poll_iter() {
match event {
sdl2::event::Event::Quit {..} | sdl2::event::Event::KeyDown {
sdl2::event::Event::Quit {..} => break 'runner,
sdl2::event::Event::KeyDown {
keycode: Some(sdl2::keyboard::Keycode::Escape), .. } => {break 'runner},
sdl2::event::Event::KeyDown {
keycode: Some(sdl2::keyboard::Keycode::RightBracket), .. } => {
println!("Increasing cpu clock from {} Hz to {} Hz", cpu.clock.clock_hz, cpu.clock.clock_hz + 10);
cpu.clock.clock_hz += 10;
},
sdl2::event::Event::KeyDown {
keycode: Some(sdl2::keyboard::Keycode::LeftBracket), .. } => {
println!("Decreasing cpu clock from {} Hz to {} Hz", cpu.clock.clock_hz, cpu.clock.clock_hz - 10);
cpu.clock.clock_hz -= 10;
},
sdl2::event::Event::KeyDown { keycode: Some(keycode), ..} => {
if let Some(key_index) = cpu.keypad.compute_keycode(keycode) {
cpu.keypad.press(key_index);
}
},
sdl2::event::Event::KeyUp { keycode: Some(keycode), ..} => {
if let Some(key_index) = cpu.keypad.compute_keycode(keycode) {
cpu.keypad.release(key_index);
}
},
_ => {}
}
}
display_buffer.random();
display.draw(&display_buffer.0)
cpu.delay_timer.tick();
cpu.sound_timer.tick();
if cpu.clock.tick() {
let opcode = OpCodes::init(fetch(&mut cpu));
decode(&opcode, &mut cpu);
if opcode.nible_1 == 0xD {
display.draw(&cpu.display_buffer.0)
}
}
}
}
pub fn fetch(ram: Ram, pc: &mut ProgramCounter) -> u16{
let opcode = ram.read16(pc.get());
pc.increase();
fn load_rom(filename: &str, cpu: &mut CPU) {
let mut f = std::fs::File::open(&filename).expect("no file found");
let metadata = std::fs::metadata(&filename).expect("unable to read metadata");
let mut buffer = vec![0; metadata.len() as usize];
f.read(&mut buffer).expect("buffer overflow");
cpu.ram.load_rom(&buffer);
}
fn fetch(cpu: &mut CPU) -> u16 {
let opcode = cpu.ram.read16(cpu.pc.get());
cpu.pc.increase();
opcode
}
pub fn decode() {}
fn decode(opcode: &OpCodes, cpu: &mut CPU) {
if opcode.opcode == 0x00E0 {
op_00e0(cpu);
} else if opcode.nible_1 == 0x1 {
op1nnn(cpu, opcode.get_nnn() as usize);
} else if opcode.opcode == 0x00EE {
op00ee(cpu);
} else if opcode.nible_1 == 0x2 {
op2nnn(cpu, opcode.get_nnn() as usize);
} else if opcode.nible_1 == 0x3 {
op3xnn(cpu, opcode.get_x(), opcode.get_nn());
} else if opcode.nible_1 == 0x4 {
op4xnn(cpu, opcode.get_x(), opcode.get_nn());
} else if opcode.nible_1 == 0x5 {
op5xy0(cpu, opcode.get_x(), opcode.get_y());
} else if opcode.nible_1 == 0x9 {
op9xy0(cpu, opcode.get_x(), opcode.get_y());
} else if opcode.nible_1 == 0x6 {
op6xnn(cpu, opcode.get_x(), opcode.get_nn());
} else if opcode.nible_1 == 0x7 {
op7xnn(cpu, opcode.get_x(), opcode.get_nn());
} else if opcode.nible_1 == 0x8 && opcode.nible_4 == 0x0 {
op8xy0(cpu, opcode.get_x(), opcode.get_y());
} else if opcode.nible_1 == 0x8 && opcode.nible_4 == 0x1 {
op8xy1(cpu, opcode.get_x(), opcode.get_y());
} else if opcode.nible_1 == 0x8 && opcode.nible_4 == 0x2 {
op8xy2(cpu, opcode.get_x(), opcode.get_y());
} else if opcode.nible_1 == 0x8 && opcode.nible_4 == 0x3 {
op8xy3(cpu, opcode.get_x(), opcode.get_y());
} else if opcode.nible_1 == 0x8 && opcode.nible_4 == 0x4 {
op8xy4(cpu, opcode.get_x(), opcode.get_y());
} else if opcode.nible_1 == 0x8 && opcode.nible_4 == 0x5 {
op8xy5(cpu, opcode.get_x(), opcode.get_y());
} else if opcode.nible_1 == 0x8 && opcode.nible_4 == 0x6 {
op8xy6(cpu, opcode.get_x(), opcode.get_y());
} else if opcode.nible_1 == 0x8 && opcode.nible_4 == 0x7 {
op8xy7(cpu, opcode.get_x(), opcode.get_y());
} else if opcode.nible_1 == 0x8 && opcode.nible_4 == 0xE {
op8xye(cpu, opcode.get_x(), opcode.get_y());
} else if opcode.nible_1 == 0xA {
opannn(cpu, opcode.get_nnn() as usize);
} else if opcode.nible_1 == 0xB {
opbnnn(cpu, opcode.get_nnn() as usize);
} else if opcode.nible_1 == 0xC {
opcxnn(cpu, opcode.get_x(), opcode.get_nn());
} else if opcode.nible_1 == 0xD {
opdxyn(cpu, opcode.get_x(), opcode.get_y(), opcode.get_n());
} else if opcode.nible_1 == 0xE && opcode.nible_3 == 0x9 && opcode.nible_4 == 0xE {
opex9e(cpu, opcode.get_x());
} else if opcode.nible_1 == 0xE && opcode.nible_3 == 0x9 && opcode.nible_4 == 0xE {
opex9e(cpu, opcode.get_x());
} else if opcode.nible_1 == 0xE && opcode.nible_3 == 0xA && opcode.nible_4 == 0x1 {
opexa1(cpu, opcode.get_x());
} else if opcode.nible_1 == 0xF && opcode.nible_3 == 0x0 && opcode.nible_4 == 0x7 {
opfx07(cpu, opcode.get_x());
} else if opcode.nible_1 == 0xF && opcode.nible_3 == 0x1 && opcode.nible_4 == 0x5 {
opfx15(cpu, opcode.get_x());
} else if opcode.nible_1 == 0xF && opcode.nible_3 == 0x1 && opcode.nible_4 == 0x8 {
opfx18(cpu, opcode.get_x());
} else if opcode.nible_1 == 0xF && opcode.nible_3 == 0x1 && opcode.nible_4 == 0xE {
opfx1e(cpu, opcode.get_x());
} else if opcode.nible_1 == 0xF && opcode.nible_3 == 0x0 && opcode.nible_4 == 0xA {
opfx0a(cpu, opcode.get_x());
} else if opcode.nible_1 == 0xF && opcode.nible_3 == 0x2 && opcode.nible_4 == 0x9 {
opfx29(cpu, opcode.get_x());
} else if opcode.nible_1 == 0xF && opcode.nible_3 == 0x3 && opcode.nible_4 == 0x3 {
opfx33(cpu, opcode.get_x());
} else if opcode.nible_1 == 0xF && opcode.nible_3 == 0x5 && opcode.nible_4 == 0x5 {
opfx55(cpu, opcode.get_x());
} else if opcode.nible_1 == 0xF && opcode.nible_3 == 0x6 && opcode.nible_4 == 0x5 {
opfx65(cpu, opcode.get_x());
} else {
println!{"Unknown instruction: {:04x}", opcode.opcode};
}
}
// fn execute() {}
pub fn execute() {}
// fn op_0NNN() {}//ignore
// CLS
// Clear the display, turning all pixels off
fn op_00e0(cpu: &mut CPU) {
cpu.display_buffer.clear();
}
// JMP
// Set PC to NNN, causing the program to jump to that memory location
fn op1nnn(cpu: &mut CPU, value: usize) {
cpu.pc.set(value);
}
fn op00ee(cpu: &mut CPU) {
let value = cpu.stack.pop();
match value {
Some(value) => {
cpu.pc.set(value);
}
_ => {}
}
}
fn op2nnn(cpu: &mut CPU, value: usize) {
cpu.stack.push(cpu.pc.get());
cpu.pc.set(value);
}
fn op3xnn(cpu: &mut CPU, register_x: usize, value: u8) {
if cpu.registers.get(register_x) == value {
cpu.pc.increase();
}
}
fn op4xnn(cpu: &mut CPU, register_x: usize, value: u8) {
if cpu.registers.get(register_x) != value {
cpu.pc.increase();
}
}
fn op5xy0(cpu: &mut CPU, register_x: usize, register_y: usize) {
if cpu.registers.get(register_x) == cpu.registers.get(register_y) {
cpu.pc.increase();
}
}
fn op9xy0(cpu: &mut CPU, register_x: usize, register_y: usize) {
if cpu.registers.get(register_x) != cpu.registers.get(register_y) {
cpu.pc.increase();
}
}
// SET
// Set the register VX to the value NN
fn op6xnn(cpu: &mut CPU, register: usize, value: u8) {
cpu.registers.set(register, value);
}
// ADD
// Add the value NN to VX. VF is ignored
fn op7xnn(cpu: &mut CPU, register: usize, value: u8) {
let nn = value as u16;
let vx = cpu.registers.get(register) as u16;
let value = (nn + vx) & 0xFF;
let value = value as u8;
cpu.registers.set(register, value);
}
fn op8xy0(cpu: &mut CPU, register_x: usize, register_y: usize) {
cpu.registers.set(register_x, cpu.registers.get(register_y));
}
fn op8xy1(cpu: &mut CPU, register_x: usize, register_y: usize) {
let vx = cpu.registers.get(register_x);
let vy = cpu.registers.get(register_y);
cpu.registers.set(register_x, vx | vy);
}
fn op8xy2(cpu: &mut CPU, register_x: usize, register_y: usize) {
let vx = cpu.registers.get(register_x);
let vy = cpu.registers.get(register_y);
cpu.registers.set(register_x, vx & vy);
}
fn op8xy3(cpu: &mut CPU, register_x: usize, register_y: usize) {
let vx = cpu.registers.get(register_x);
let vy = cpu.registers.get(register_y);
cpu.registers.set(register_x, vx ^ vy);
}
fn op8xy4(cpu: &mut CPU, register_x: usize, register_y: usize) {
let vx = cpu.registers.get(register_x) as u16;
let vy = cpu.registers.get(register_y) as u16;
let value = (vx + vy) & 0xFF;
cpu.registers.set(register_x, value as u8);
}
fn op8xy5(cpu: &mut CPU, register_x: usize, register_y: usize) {
let vx = cpu.registers.get(register_x);
let vy = cpu.registers.get(register_y);
cpu.registers.set(register_x, vx.wrapping_sub(vy));
cpu.registers.set(0xF, if vx > vy {1} else {0});
}
fn op8xy6(cpu: &mut CPU, register_x: usize, register_y: usize) {
let vy = cpu.registers.get(register_y);
let vx = cpu.registers.get(register_x);
cpu.registers.set(register_x, vy >> 1);
cpu.registers.set(0xF, vx & 0x1);
}
fn op8xy7(cpu: &mut CPU, register_x: usize, register_y: usize) {
let vx = cpu.registers.get(register_x);
let vy = cpu.registers.get(register_y);
cpu.registers.set(register_x, vy.wrapping_sub(vx));
cpu.registers.set(0xF, if vy > vx {1} else {0});
}
fn op8xye(cpu: &mut CPU, register_x: usize, register_y: usize) {
let vy = cpu.registers.get(register_y);
let vx = cpu.registers.get(register_x);
cpu.registers.set(register_x, vy << 1);
cpu.registers.set(0xF, (vx & 0x80) >> 7);
}
// IND
// Set index register I to the value NNN
fn opannn(cpu: &mut CPU, value: usize) {
cpu.index_register = value;
}
fn opbnnn(cpu: &mut CPU, value: usize) {
let v0 = cpu.registers.get(0x0) as usize;
cpu.pc.set(value + v0);
}
fn opcxnn(cpu: &mut CPU, register_x: usize, value: u8) {
let mut rng = rand::thread_rng();
cpu.registers.set(register_x,rng.gen_range(0x0..0xFF) & value);
}
// DIS
// Display
fn opdxyn(cpu: &mut CPU, register_x: usize, register_y: usize, value: u8) {
let mut vf: bool = false;
let value = value as usize;
let ori_x = cpu.registers.get(register_x) as usize % DISPLAY_WIDTH;
let ori_y = cpu.registers.get(register_y) as usize % DISPLAY_HEIGHT;
for row in 0..value {
let y = ori_y + row;
if y >= DISPLAY_HEIGHT {
break;
}
let sprite = cpu.ram.read8(cpu.index_register + row);
for pixel_position in 0..8 {
let x = ori_x + pixel_position;
if x >= DISPLAY_WIDTH {
break;
}
let memory_pixel: bool = (sprite & (1 << (7 - pixel_position))) > 0;
let display_pixel: bool = cpu.display_buffer.0[x][y];
cpu.display_buffer.0[x][y] = memory_pixel ^ display_pixel;
vf = (memory_pixel && display_pixel) || vf;
}
}
cpu.registers.set(0xF, if vf {1} else {0});
}
fn opex9e(cpu: &mut CPU, register_x: usize) {
if cpu.keypad.get(cpu.registers.get(register_x) as usize) {
cpu.pc.increase();
}
}
fn opexa1(cpu: &mut CPU, register_x: usize) {
if !cpu.keypad.get(cpu.registers.get(register_x) as usize) {
cpu.pc.increase();
}
}
fn opfx07(cpu: &mut CPU, register_x: usize) {
cpu.registers.set(register_x, cpu.delay_timer.tick);
}
fn opfx15(cpu: &mut CPU, register_x: usize) {
cpu.delay_timer.tick = cpu.registers.get(register_x);
}
fn opfx18(cpu: &mut CPU, register_x: usize) {
cpu.sound_timer.tick = cpu.registers.get(register_x);
}
fn opfx1e(cpu: &mut CPU, register_x: usize) {
cpu.index_register += cpu.registers.get(register_x) as usize;
}
fn opfx0a(cpu: &mut CPU, register_x: usize) {
if cpu.keypad.being_pressed() == 0x10 {
cpu.pc.decrement();
} else {
cpu.registers.set(register_x, cpu.keypad.being_pressed());
}
}
fn opfx29(cpu: &mut CPU, register_x: usize) {
let char = (cpu.registers.get(register_x) & 0xF) as usize;
cpu.index_register = 0x50 + char * 5;
}
fn opfx33(cpu: &mut CPU, register_x: usize) {
let vx = cpu.registers.get(register_x);
cpu.ram.write8(cpu.index_register, vx / 100);
cpu.ram.write8(cpu.index_register + 1, vx / 10 % 10);
cpu.ram.write8(cpu.index_register + 2, vx % 10);
}
fn opfx55(cpu: &mut CPU, register_x: usize) {
let i = cpu.index_register;
for regs in 0x0..(register_x + 1) {
cpu.ram.write8(i + regs, cpu.registers.get(regs));
}
// cpu.index_register += register_x + 1;
}
fn opfx65(cpu: &mut CPU, register_x: usize) {
let i = cpu.index_register;
for regs in 0x0..(register_x + 1) {
cpu.registers.set(regs, cpu.ram.read8(i + regs));
}
// cpu.index_register += register_x + 1;
}

View File

@ -1,21 +1,15 @@
use sdl2::pixels::Color;
use sdl2::rect::Rect;
use sdl2::render::Canvas;
use sdl2::Sdl;
use sdl2::video::Window;
const WIDTH: usize = 64;
const HEIGHT: usize = 32;
pub struct Display {
canvas: Canvas<Window>,
canvas: sdl2::render::Canvas<sdl2::video::Window>,
scale: u32,
off_color: Color,
on_color: Color
off_color: sdl2::pixels::Color,
on_color: sdl2::pixels::Color
}
impl Display {
pub fn init(sdl_context: &Sdl, scale: u32) -> Display {
pub fn init(sdl_context: &sdl2::Sdl, scale: u32) -> Display {
let video_subsystem = sdl_context.video().unwrap();
let window = video_subsystem.window("Chip-8", WIDTH as u32 * scale,
@ -29,8 +23,8 @@ impl Display {
Display {
canvas: canvas,
scale: scale,
off_color: Color::RGB(0, 0, 0),
on_color: Color::RGB(255, 255, 255)
off_color: sdl2::pixels::Color::RGB(0, 0, 0),
on_color: sdl2::pixels::Color::RGB(255, 255, 255)
}
}
@ -46,7 +40,7 @@ impl Display {
let y = (y as u32 * self.scale) as i32;
let width = self.scale;
let height = self.scale;
self.canvas.fill_rect(Rect::new(x, y, width, height))
self.canvas.fill_rect(sdl2::rect::Rect::new(x, y, width, height))
.expect("Failed to draw pixel");
}
}