initial commit

Cargo.toml

@@ -0,0 +1,9 @@
+[package]
+name = "sim"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]
+pixels = "0.15.0"
+winit = "0.30.13"
+winit_input_helper = "0.17.0"

src/cpu.rs

@@ -0,0 +1,330 @@
+use std::{
+    hint::{likely, unlikely},
+    io::Read,
+    process::exit,
+    sync::{Mutex, atomic::AtomicU32},
+    thread::sleep,
+    time::Duration,
+};
+
+use pixels::Pixels;
+
+enum Op2 {
+    Direct(u32),
+    Register(u8),
+}
+
+struct Reg(u8);
+enum Cond {
+    Ifeq,
+    Ifne,
+    Iflt,
+    Ifge,
+    Ifgt,
+    Ifle,
+    Ifult,
+    Ifuge,
+    Ifugt,
+    Ifule,
+}
+
+impl From<u8> for Cond {
+    fn from(value: u8) -> Self {
+        match value {
+            0b0000 => Cond::Ifeq,
+            0b0001 => Cond::Ifne,
+            0b1000 => Cond::Iflt,
+            0b1001 => Cond::Ifge,
+            0b1010 => Cond::Ifgt,
+            0b1011 => Cond::Ifle,
+            0b1100 => Cond::Ifult,
+            0b1101 => Cond::Ifuge,
+            0b1110 => Cond::Ifugt,
+            0b1111 => Cond::Ifule,
+            _ => {
+                unreachable!()
+            }
+        }
+    }
+}
+
+impl Cond {
+    fn eval(self, a: u32, b: u32) -> bool {
+        match self {
+            Cond::Ifeq => a == b,
+            Cond::Ifne => a != b,
+            Cond::Iflt => (a as i32) < (b as i32),
+            Cond::Ifge => (a as i32) >= (b as i32),
+            Cond::Ifgt => (a as i32) > (b as i32),
+            Cond::Ifle => (a as i32) <= (b as i32),
+            Cond::Ifult => a < b,
+            Cond::Ifuge => a >= b,
+            Cond::Ifugt => a > b,
+            Cond::Ifule => a <= b,
+        }
+    }
+}
+
+enum Instruction {
+    Copy(Reg, Op2),
+    Add(Reg, Reg, Op2),
+    Sub(Reg, Reg, Op2),
+    Or(Reg, Reg, Op2),
+    And(Reg, Reg, Op2),
+    Xor(Reg, Reg, Op2),
+    Lsl(Reg, Reg, Op2),
+    Lsr(Reg, Reg, Op2),
+    Asr(Reg, Reg, Op2),
+    Store(Reg, Op2, Reg),
+    Load(Reg, Reg, Op2),
+    Push(Op2),
+    Pop(Reg),
+    Skip(u8, Cond, Reg, Op2),
+    Jump(u32), //address / 4
+    Call(u32), //address / 4
+    Ret(),
+    GetStack(Reg),
+    SetStack(Op2),
+}
+
+impl From<u32> for Instruction {
+    fn from(value: u32) -> Self {
+        match value >> 30 {
+            0b00 => {
+                let t = value & (1 << 29); // 3rd bit set
+                let value = value - t;
+                let t = t != 0;
+                if t {
+                    Self::Call(value)
+                } else {
+                    Self::Jump(value)
+                }
+            }
+            fmt => {
+                let imediate = (value & (1 << 28)) != 0;
+                let s = (value & 1 << 27) != 0;
+                const MASK: u32 = 0b1111;
+                let opcode = (value >> 24) & MASK;
+                let rd = Reg(((value >> 20) & MASK) as u8);
+                let rx = Reg(((value >> 16) & MASK) as u8);
+                let op2 = {
+                    if imediate {
+                        let value = if s {
+                            value | 0xFFFF0000
+                        } else {
+                            value & 0x0000FFFF
+                        };
+                        Op2::Direct(value)
+                    } else {
+                        Op2::Register((value >> 12 & MASK) as u8)
+                    }
+                };
+                match (fmt, opcode) {
+                    (1, 0b0000) => Self::Copy(rd, op2),
+                    (1, 0b0001) => Self::Add(rd, rx, op2),
+                    (1, 0b0010) => Self::Sub(rd, rx, op2),
+                    (1, 0b0011) => Self::Or(rd, rx, op2),
+                    (1, 0b0100) => Self::And(rd, rx, op2),
+                    (1, 0b0101) => Self::Xor(rd, rx, op2),
+                    (1, 0b0110) => Self::Lsl(rd, rx, op2),
+                    (1, 0b0111) => Self::Lsr(rd, rx, op2),
+                    (1, 0b1000) => Self::Asr(rd, rx, op2),
+                    (2, 0b0000) => Self::Store(rx, op2, rd),
+                    (2, 0b0001) => Self::Load(rd, rx, op2),
+                    (2, 0b0010) => Self::Push(op2),
+                    (2, 0b0011) => Self::Pop(rd),
+                    (2, 0b1000) => Self::Ret(),
+                    (2, 0b1101) => Self::GetStack(rd),
+                    (2, 0b1110) => Self::SetStack(op2),
+                    (3, skip) => Self::Skip(rd.0, (skip as u8).into(), rx, op2),
+                    _ => unreachable!(),
+                }
+            }
+        }
+    }
+}
+
+pub struct Computer<'a, 'b> {
+    ram: Box<[u32; 0x01000000 / 4]>,
+    regs: [u32; 16],
+    pc: usize,
+    sp: usize,
+    screen: &'b Mutex<Pixels<'a>>,
+    key: &'b AtomicU32,
+}
+
+fn iot() -> ! {
+    exit(1);
+}
+
+impl<'a, 'b> Computer<'a, 'b> {
+    pub fn new(filename: String, screen: &'b Mutex<Pixels<'a>>, key: &'b AtomicU32) -> Self {
+        let mut new = Self {
+            ram: Box::new([0; 0x01000000 / 4]),
+            regs: [0; 16],
+            pc: 0,
+            sp: 0,
+            screen,
+            key,
+        };
+        let mut buf = String::new();
+        std::fs::File::open(filename)
+            .unwrap()
+            .read_to_string(&mut buf)
+            .unwrap();
+        for (i, line) in buf.lines().enumerate() {
+            match u32::from_str_radix(line, 16) {
+                Ok(val) => new.ram[i] = val,
+                Err(_) => break,
+            }
+        }
+        new
+    }
+    pub fn step(&mut self) {
+        let next_opcode = self.ram[self.pc];
+        match Instruction::from(next_opcode) {
+            Instruction::Copy(reg, op2) => {
+                self.rg_wr(reg, self.resolve(op2));
+                self.pc += 1;
+            }
+            Instruction::Add(reg, reg1, op2) => {
+                self.rg_wr(reg, self.rg_r(reg1) + self.resolve(op2));
+                self.pc += 1;
+            }
+            Instruction::Sub(reg, reg1, op2) => {
+                self.rg_wr(reg, self.rg_r(reg1) - self.resolve(op2));
+                self.pc += 1;
+            }
+            Instruction::Or(reg, reg1, op2) => {
+                self.rg_wr(reg, self.rg_r(reg1) | self.resolve(op2));
+                self.pc += 1;
+            }
+            Instruction::And(reg, reg1, op2) => {
+                self.rg_wr(reg, self.rg_r(reg1) & self.resolve(op2));
+                self.pc += 1;
+            }
+            Instruction::Xor(reg, reg1, op2) => {
+                self.rg_wr(reg, self.rg_r(reg1) ^ self.resolve(op2));
+                self.pc += 1;
+            }
+            Instruction::Lsl(reg, reg1, op2) => {
+                self.rg_wr(reg, self.rg_r(reg1) << self.resolve(op2));
+                self.pc += 1;
+            }
+            Instruction::Lsr(reg, reg1, op2) => {
+                self.rg_wr(reg, self.rg_r(reg1) >> self.resolve(op2));
+                self.pc += 1;
+            }
+            Instruction::Asr(reg, reg1, op2) => {
+                self.rg_wr(reg, (self.rg_r(reg1) as i32 >> self.resolve(op2)) as u32);
+                self.pc += 1;
+            }
+            Instruction::Store(reg, op2, reg1) => {
+                let addr = (self.rg_r(reg) + self.resolve(op2)) as usize;
+                if !addr.is_multiple_of(4) {
+                    iot();
+                }
+                if addr <= 0x00ffffff {
+                    self.ram[addr / 4] = self.rg_r(reg1);
+                } else if addr <= 0x00ffffff + 480 * 640 * 4 {
+                    let addr_screen = addr - 0x01000000;
+                    let ubgr = self.rg_r(reg1);
+                    let rgba = [ubgr as u8, (ubgr >> 8) as u8, (ubgr >> 16) as u8, 0xff];
+                    let mut pixels = self.screen.lock().unwrap();
+                    let screen = pixels.frame_mut();
+                    for i in 0..4 {
+                        screen[addr_screen + i] = rgba[i];
+                    }
+                } else {
+                    iot();
+                }
+                self.pc += 1;
+            }
+            Instruction::Load(reg, reg1, op2) => {
+                let addr = (self.rg_r(reg1) + self.resolve(op2)) as usize;
+                if !addr.is_multiple_of(4) {
+                    iot();
+                }
+                self.rg_wr(
+                    reg,
+                    if addr <= 0x00ffffff {
+                        self.ram[addr / 4]
+                    } else if addr <= 0x00ffffff + 480 * 640 * 4 {
+                        let pixels = self.screen.lock().unwrap();
+                        let buffer = pixels.frame();
+                        let mut res = 0;
+                        let addr_screen = addr - 0x01000000;
+                        for i in 0..3 {
+                            res += (buffer[addr_screen + i] as u32) << (i as u32 * 8)
+                        }
+                        res
+                    } else if addr == 0x01200000 {
+                        self.key.load(std::sync::atomic::Ordering::Relaxed)
+                    } else {
+                        iot();
+                    },
+                );
+                self.pc += 1;
+            }
+            Instruction::Push(op2) => {
+                self.sp -= 1;
+                self.ram[self.sp] = self.resolve(op2);
+                self.pc += 1;
+            }
+            Instruction::Pop(reg) => {
+                self.rg_wr(reg, self.ram[self.sp]);
+                self.sp += 1;
+                self.pc += 1;
+            }
+            Instruction::Skip(d, cond, reg, op2) => {
+                self.pc += 1;
+                if cond.eval(self.rg_r(reg), self.resolve(op2)) {
+                    self.pc += d as usize
+                }
+            }
+            Instruction::Jump(mut addr) => {
+                if addr & (1 << 28) != 0 {
+                    addr += 7 << 29;
+                } else if unlikely(addr == 0) {
+                    sleep(Duration::from_hours(1));
+                }
+                self.pc = (addr + self.pc as u32) as usize;
+            }
+            Instruction::Call(addr) => {
+                self.sp -= 1;
+                self.ram[self.sp] = ((self.pc << 2) + 4) as u32;
+                self.pc += addr as usize;
+                self.pc &= 0x3FFFFFFF; //wrapping on 30 bit pc
+            }
+            Instruction::Ret() => {
+                self.pc = (self.ram[self.sp] >> 2) as usize;
+                self.sp += 1;
+            }
+            Instruction::GetStack(reg) => {
+                self.rg_wr(reg, (self.sp << 2) as u32);
+                self.pc += 1;
+            }
+            Instruction::SetStack(op2) => {
+                let v = self.resolve(op2);
+                if likely(v.is_multiple_of(4)) {
+                    self.sp = (v >> 2) as usize;
+                } else {
+                    self.sp = usize::MAX //Yes, that means that clever program using sp to store information wont work on my emulator. Deal with it
+                }
+                self.pc += 1;
+            }
+        };
+    }
+    fn resolve(&self, op2: Op2) -> u32 {
+        match op2 {
+            Op2::Direct(v) => v,
+            Op2::Register(r) => self.regs[r as usize],
+        }
+    }
+    fn rg_wr(&mut self, reg: Reg, v: u32) {
+        self.regs[reg.0 as usize] = v
+    }
+    fn rg_r(&self, reg: Reg) -> u32 {
+        self.regs[reg.0 as usize]
+    }
+}

src/main.rs

@@ -0,0 +1,139 @@
+#![feature(likely_unlikely)]
+#![deny(clippy::all)]
+
+use std::env::args;
+use std::process::exit;
+use std::sync::atomic::AtomicU32;
+use std::sync::{Arc, Mutex};
+use std::thread::{scope, sleep};
+use std::time::Duration;
+
+use pixels::{Error, Pixels, SurfaceTexture};
+use winit::dpi::LogicalSize;
+use winit::event::{Event, WindowEvent};
+use winit::event_loop::EventLoop;
+use winit::keyboard::KeyCode;
+use winit::platform::scancode::PhysicalKeyExtScancode;
+use winit::window::Window;
+use winit_input_helper::WinitInputHelper;
+
+use crate::cpu::Computer;
+
+const WIDTH: u32 = 640;
+const HEIGHT: u32 = 480;
+
+mod cpu;
+
+fn main() -> Result<(), Error> {
+    let event_loop = EventLoop::new().unwrap();
+    let mut input = WinitInputHelper::new();
+    let window = {
+        let size = LogicalSize::new((WIDTH * 3) as f64, (HEIGHT * 3) as f64);
+        #[allow(deprecated)]
+        Arc::new(
+            event_loop
+                .create_window(
+                    Window::default_attributes()
+                        .with_title("bisare screen")
+                        .with_inner_size(size)
+                        .with_min_inner_size(size),
+                )
+                .unwrap(),
+        )
+    };
+
+    let pixels = Mutex::new({
+        let window_size = window.inner_size();
+        let surface_texture = SurfaceTexture::new(window_size.width, window_size.height, &window);
+        Pixels::new(WIDTH, HEIGHT, surface_texture)?
+    });
+
+    let keyboard = AtomicU32::new(0);
+    let program = args()
+        .nth(1)
+        .expect("you must supply the exec name as the first argument");
+    let kbref = &keyboard;
+    let pixelref = &pixels;
+    scope(|sc| {
+        sc.spawn(|| {
+            let mut simulation = Computer::new(program, pixelref, kbref);
+            loop {
+                simulation.step();
+            }
+        });
+
+        #[allow(deprecated)]
+        let res = event_loop.run(|event, elwt| {
+            match event {
+                Event::Resumed => {}
+                Event::NewEvents(_) => input.step(),
+                Event::AboutToWait => input.end_step(),
+                Event::DeviceEvent { event, .. } => {
+                    input.process_device_event(&event);
+                }
+                Event::WindowEvent { event, .. } => {
+                    // Draw the current frame
+                    if event == WindowEvent::RedrawRequested {
+                        if let Err(_) = pixels.lock().unwrap().render() {
+                            elwt.exit();
+                            return;
+                        }
+                        sleep(Duration::from_millis(30));
+                    }
+
+                    if let WindowEvent::KeyboardInput {
+                        device_id: _,
+                        ref event,
+                        is_synthetic: _,
+                    } = event
+                    {
+                        match event.state {
+                            winit::event::ElementState::Pressed => {
+                                if let Some(val) = event.physical_key.to_scancode() {
+                                    println!("key with code {val} was pressed");
+                                    kbref.store(val, std::sync::atomic::Ordering::Relaxed);
+                                }
+                            }
+                            winit::event::ElementState::Released => {
+                                println!("key released");
+                                kbref.store(0, std::sync::atomic::Ordering::Relaxed)
+                            }
+                        }
+                    }
+
+                    // Handle input events
+                    if input.process_window_event(&event) {
+                        // Close events
+                        if input.close_requested() {
+                            elwt.exit();
+                            return;
+                        }
+
+                        // Resize the window
+                        if let Some(size) = input.window_resized() {
+                            if let Err(_) = pixels
+                                .lock()
+                                .unwrap()
+                                .resize_surface(size.width, size.height)
+                            {
+                                elwt.exit();
+                                return;
+                            }
+                        }
+
+                        // Update internal state and request a redraw
+                        window.request_redraw();
+                    }
+                }
+                _ => {}
+            }
+        });
+        match res {
+            Ok(_) => exit(0),
+            Err(e) => {
+                println!("{e}");
+                exit(1);
+            }
+        }
+    })
+}