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added some op codes
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@aowalke2
aowalke2 committed Mar 9, 2024
1 parent 37d1593 commit 82d2b6e
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Showing 2 changed files with 171 additions and 62 deletions.
178 changes: 136 additions & 42 deletions src/cpu.rs
View file
Original file line number Diff line number Diff line change
@@ -1,4 +1,6 @@
pub trait Memory {
const PROGRAM_START: u16 = 0x200;

trait Memory {
fn mem_read(&self, address: u16) -> u8;

fn mem_read_16(&self, address: u16) -> u16 {
Expand All @@ -17,13 +19,21 @@ pub trait Memory {
}
}

trait Stack {
fn stack_push(&mut self, address: u16);
fn stack_pop(&mut self) -> u16;
}

#[derive(Debug, Clone)]
pub struct Cpu {
program_counter: u16,
index_register: u16,
stack: Vec<u16>,
stack_pointer: u8,
stack: [u16; 16],
registers: [u8; 16],
memory: [u8; 4096],
delay_timer: u8,
sound_timer: u8,
}

impl Memory for Cpu {
Expand All @@ -36,22 +46,68 @@ impl Memory for Cpu {
}
}

impl Stack for Cpu {
fn stack_push(&mut self, address: u16) {
self.stack[self.stack_pointer as usize] = address;
self.stack_pointer += 1;
}

fn stack_pop(&mut self) -> u16 {
self.stack_pointer -= 1;
self.stack[self.stack_pointer as usize]
}
}

impl Cpu {
pub fn new() -> Cpu {
Self {
program_counter: 0,
index_register: 0,
stack: vec![0; 16],
stack_pointer: 0,
stack: [0; 16],
registers: [0; 16],
memory: [0; 4096],
delay_timer: 0,
sound_timer: 0,
}
}

fn cls(&mut self) {
todo!()
}

fn ret(&mut self) {
self.program_counter = self.stack_pop();
}

fn jp(&mut self, opcode: u16) {
self.program_counter = opcode & 0x0FFF;
}

fn call(&mut self, opcode: u16) {
self.stack_push(self.program_counter);
self.program_counter = opcode & 0x0FFF;
}

pub fn tick_timers(&mut self) {
if self.delay_timer > 0 {
self.delay_timer -= 1;
}

if self.sound_timer > 0 {
if self.sound_timer == 1 {
//BEEP
}

self.sound_timer -= 1;
}
}

pub fn load(&mut self, program: &[u8]) {
for i in 0..program.len() as u16 {
self.mem_write(0x200 + i, program[i as usize]);
self.mem_write(PROGRAM_START + i, program[i as usize]);
}
self.program_counter = 0x200;
self.program_counter = PROGRAM_START;
}

pub fn fetch(&mut self) -> u16 {
Expand All @@ -60,40 +116,49 @@ impl Cpu {
opcode
}

pub fn decode_and_execute(&mut self, opcode: u16) {
match opcode {
0x00e0 => println!("CLS"),
0x00ee => println!("RET"),
opcode if opcode >> 12 == 0 => println!("SYS addr: {opcode}"),
opcode if opcode >> 12 == 1 => println!("JP addr: {opcode}"),
opcode if opcode >> 12 == 2 => println!("CALL addr: {opcode}"),
opcode if opcode >> 12 == 3 => println!("SE Vx, byte: {opcode}"),
opcode if opcode >> 12 == 4 => println!("SNE Vx, byte: {opcode}"),
opcode if opcode >> 12 == 5 => println!("SE Vx, Vy: {opcode}"),
opcode if opcode >> 12 == 6 => println!("LD Vx, byte: {opcode}"),
opcode if opcode >> 12 == 7 => println!("ADD Vx, byte: {opcode}"),
opcode if opcode >> 12 == 8 && opcode & 0xf == 0 => println!("LD Vx, Vy: {opcode}"),
opcode if opcode >> 12 == 8 && opcode & 0xf == 1 => println!("OR Vx, Vy: {opcode}"),
opcode if opcode >> 12 == 8 && opcode & 0xf == 2 => println!("AND Vx, Vy: {opcode}"),
opcode if opcode >> 12 == 8 && opcode & 0xf == 3 => println!("XOR Vx, Vy: {opcode}"),
opcode if opcode >> 12 == 8 && opcode & 0xf == 4 => println!("ADD Vx, Vy: {opcode}"),
opcode if opcode >> 12 == 8 && opcode & 0xf == 5 => println!("SUB Vx, Vy: {opcode}"),
opcode if opcode >> 12 == 8 && opcode & 0xf == 6 => {
println!("SHR Vx {{, Vy}}: {opcode}")
}
opcode if opcode >> 12 == 8 && opcode & 0xf == 7 => println!("SUBN Vx, Vy: {opcode}"),
opcode if opcode >> 12 == 8 && opcode & 0xf == 0xE => {
println!("SHL Vx {{, Vy}}: {opcode}")
}
opcode if opcode >> 12 == 9 => println!("SNE Vx, Vy: {opcode}"),
opcode if opcode >> 12 == 0xA => println!("LD I, addr: {opcode}"),
opcode if opcode >> 12 == 0xB => println!("JP V0, addr: {opcode}"),
opcode if opcode >> 12 == 0xC => println!("RND Vx, byte: {opcode}"),
opcode if opcode >> 12 == 0xD => println!("DRW Vx, Vy, nibble: {opcode}"),
opcode if opcode >> 12 == 0xE && opcode & 0xff == 0x9E => println!("SKP Vx: {opcode}"),
opcode if opcode >> 12 == 0xE && opcode & 0xff == 0xA1 => println!("SKNP Vx: {opcode}"),

_ => panic!("Opcode not defined"),
pub fn execute(&mut self, opcode: u16) {
let nibble1 = (opcode & 0xF000) >> 12;
let nibble2 = (opcode & 0x0F00) >> 8;
let nibble3 = (opcode & 0x00F0) >> 4;
let nibble4 = opcode & 0x000F;

match (nibble1, nibble2, nibble3, nibble4) {
(0, 0, 0, 0) => println!("NOP"),
(0, 0, 0xe, 0) => self.cls(),
(0, 0, 0xE, 0xE) => self.ret(),
(1, _, _, _) => self.jp(opcode),
(2, _, _, _) => self.call(opcode),
(3, _, _, _) => println!("SE Vx, byte: {opcode}"),
(4, _, _, _) => println!("SNE Vx, byte: {opcode}"),
(5, _, _, _) => println!("SE Vx, Vy: {opcode}"),
(6, _, _, _) => println!("LD Vx, byte: {opcode}"),
(7, _, _, _) => println!("ADD Vx, byte: {opcode}"),
(8, _, _, 0) => println!("LD Vx, Vy: {opcode}"),
(8, _, _, 1) => println!("OR Vx, Vy: {opcode}"),
(8, _, _, 2) => println!("AND Vx, Vy: {opcode}"),
(8, _, _, 3) => println!("XOR Vx, Vy: {opcode}"),
(8, _, _, 4) => println!("ADD Vx, Vy: {opcode}"),
(8, _, _, 5) => println!("SUB Vx, Vy: {opcode}"),
(8, _, _, 6) => println!("SHR Vx {{, Vy}}: {opcode}"),
(8, _, _, 7) => println!("SUBN Vx, Vy: {opcode}"),
(8, _, _, 0xE) => println!("SHL Vx {{, Vy}}: {opcode}"),
(9, _, _, _) => println!("SNE Vx, Vy: {opcode}"),
(0xA, _, _, _) => println!("LD I, addr: {opcode}"),
(0xB, _, _, _) => println!("JP V0, addr: {opcode}"),
(0xC, _, _, _) => println!("RND Vx, byte: {opcode}"),
(0xD, _, _, _) => println!("DRW Vx, Vy, nibble: {opcode}"),
(0xE, _, 9, 0xE) => println!("SKP Vx: {opcode}"),
(0xE, _, 0xA, 1) => println!("SKNP Vx: {opcode}"),
(0xF, _, 0, 7) => println!("LD Vx, DT: {opcode}"),
(0xF, _, 0, 0xA) => println!("LD Vx, K: {opcode}"),
(0xF, _, 1, 5) => println!("LD DT, Vx: {opcode}"),
(0xF, _, 1, 8) => println!("LD ST, Vx: {opcode}"),
(0xF, _, 1, 0xE) => println!("ADD I, Vx: {opcode}"),
(0xF, _, 2, 9) => println!("LD F, Vx: {opcode}"),
(0xF, _, 3, 3) => println!("LD B, Vx: {opcode}"),
(0xF, _, 5, 5) => println!("LD [I], Vx: {opcode}"),
(0xF, _, 6, 5) => println!("LD Vx, [I]: {opcode}"),
(_, _, _, _) => unimplemented!("Opcode not defined: {opcode}"),
}
}
}
Expand All @@ -105,16 +170,16 @@ mod test {
#[test]
fn test_memory() {
let mut cpu = Cpu::new();
cpu.mem_write(0x200, 0x20);
assert_eq!(cpu.mem_read(0x200), 0x20);
cpu.mem_write(PROGRAM_START, 0x20);
assert_eq!(cpu.mem_read(PROGRAM_START), 0x20);
}

#[test]
fn test_load() {
let program = [7; 1000];
let mut cpu = Cpu::new();
cpu.load(&program);
assert_eq!(cpu.program_counter, 0x200);
assert_eq!(cpu.program_counter, PROGRAM_START);
assert_eq!(cpu.mem_read(0x25f), 7);
}

Expand All @@ -127,4 +192,33 @@ mod test {
assert_eq!(cpu.program_counter, 0x202);
assert_eq!(operation, 0xffff);
}

#[test]
fn test_cls() {
assert!(true);
}

#[test]
fn test_ret() {
let mut cpu = Cpu::new();
cpu.stack_push(0x1111);
cpu.ret();
assert_eq!(cpu.program_counter, 0x1111);
}

#[test]
fn test_jp() {
let mut cpu = Cpu::new();
cpu.jp(0x1111);
assert_eq!(cpu.program_counter, 0x0111);
}

#[test]
fn test_call() {
let mut cpu = Cpu::new();
cpu.program_counter = PROGRAM_START;
cpu.call(0x2222);
assert_eq!(cpu.stack_pop(), 0x0200);
assert_eq!(cpu.program_counter, 0x0222)
}
}
55 changes: 35 additions & 20 deletions src/main.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -4,24 +4,39 @@ pub mod cpu;

fn main() {
let mut cpu = Cpu::new();
cpu.decode_and_execute(0x00e0);
cpu.decode_and_execute(0x00ee);
cpu.decode_and_execute(0x0012);
cpu.decode_and_execute(0x1012);
cpu.decode_and_execute(0x2012);
cpu.decode_and_execute(0x3012);
cpu.decode_and_execute(0x4012);
cpu.decode_and_execute(0x5012);
cpu.decode_and_execute(0x6012);
cpu.decode_and_execute(0x7012);
cpu.decode_and_execute(0x8010);
cpu.decode_and_execute(0x8011);
cpu.decode_and_execute(0x8012);
cpu.decode_and_execute(0x8013);
cpu.decode_and_execute(0x8014);
cpu.decode_and_execute(0x8015);
cpu.decode_and_execute(0x8016);
cpu.decode_and_execute(0x8017);
cpu.decode_and_execute(0x801E);
cpu.decode_and_execute(0x9010);
cpu.execute(0x00e0);
cpu.execute(0x00ee);
cpu.execute(0x0012);
cpu.execute(0x1012);
cpu.execute(0x2012);
cpu.execute(0x3012);
cpu.execute(0x4012);
cpu.execute(0x5012);
cpu.execute(0x6012);
cpu.execute(0x7012);
cpu.execute(0x8010);
cpu.execute(0x8011);
cpu.execute(0x8012);
cpu.execute(0x8013);
cpu.execute(0x8014);
cpu.execute(0x8015);
cpu.execute(0x8016);
cpu.execute(0x8017);
cpu.execute(0x801E);
cpu.execute(0x9010);
cpu.execute(0xA012);
cpu.execute(0xB012);
cpu.execute(0xC012);
cpu.execute(0xD012);
cpu.execute(0xE09E);
cpu.execute(0xE1A1);
cpu.execute(0xF007);
cpu.execute(0xF00A);
cpu.execute(0xF015);
cpu.execute(0xF018);
cpu.execute(0xF01E);
cpu.execute(0xF029);
cpu.execute(0xF033);
cpu.execute(0xF055);
cpu.execute(0xF065);
}

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