feat: skeleton fetch/decode/execute loop

src/.state.rs.rustfmt

@@ -0,0 +1,67 @@
+use crate::display::Display;
+use crate::operation::Operation;
+
+const FONT: [u8; 80] = [
+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
+];
+
+pub struct State {
+    memory: [u8; 4096],
+    pc: usize,
+    index: usize,
+    stack: Vec<u16>,
+    delay_timer: u8,
+    sound_timer: u8,
+    variables: [u8; 16],
+    display: Display,
+}
+
+impl State {
+    pub fn new() -> Self {
+        Self {
+            memory: [0; 4096],
+            pc: 0,
+            index: 0,
+            stack: vec![],
+            delay_timer: 0,
+            sound_timer: 0,
+            variables: [0; 16],
+            display: Display::new()
+        }
+    }
+
+    pub fn default() -> Self {
+        let instance = Self::new();
+
+        // TODO: Initialise memory with font (and other) data
+
+        instance
+    }
+
+    pub fn next_operation(&mut self) -> Operation {
+        let opcode = (self.memory[self.pc] as u16) << 8 + self.memory[self.pc + 1] as u16;
+        self.pc += 2;
+        Operation::new(opcode)
+    }
+
+    pub fn update(&mut self, op: Operation) {
+        match op {
+            _ => ()
+        }
+    }
+}

src/display.rs

@@ -0,0 +1,11 @@
+pub struct Display {
+    buffer: [u32; 64 * 32],
+}
+
+impl Display {
+    pub fn new() -> Self {
+        Self {
+            buffer: [0; 64 * 32],
+        }
+    }
+}

src/main.rs

@@ -1,23 +1,14 @@
-use minifb::{Key, Window, WindowOptions};
+use state::State;
 
-const WIDTH: usize = 640;
-const HEIGHT: usize = 360;
+pub mod display;
+pub mod operation;
+pub mod state;
 
 fn main() {
-    let mut buf = vec![0u32; WIDTH * HEIGHT];
+    let mut state = State::default();
 
-    let mut window = Window::new("Test", WIDTH, HEIGHT, WindowOptions::default())
-        .unwrap_or_else(|e| panic!("{}", e));
-
-    window.limit_update_rate(Some(std::time::Duration::from_micros(16600)));
-
-    while window.is_open() && !window.is_key_down(Key::Escape) {
-        for (i, pixel) in buf.iter_mut().enumerate() {
-            let x: u32 = (i % WIDTH) as u32;
-            let y: u32 = (i / WIDTH) as u32;
-            *pixel = (x % (y + 1)) % u32::MAX;
-        }
-
-        window.update_with_buffer(&buf, WIDTH, HEIGHT).unwrap()
+    loop {
+        let op = state.next_operation();
+        state.update(op);
     }
 }

src/operation.rs

@@ -0,0 +1,12 @@
+#[derive(PartialEq, Eq, Clone, Copy, Debug)]
+pub enum Operation {
+    ClearScreen,
+}
+
+impl Operation {
+    pub fn new(opcode: u16) -> Self {
+        match opcode {
+            _ => Self::ClearScreen,
+        }
+    }
+}

src/state.rs

@@ -0,0 +1,69 @@
+use crate::display::Display;
+use crate::operation::Operation;
+
+const FONT: [u8; 80] = [
+    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
+];
+
+pub struct State {
+    memory: [u8; 4096],
+    pc: usize,
+    index: usize,
+    stack: Vec<u16>,
+    delay_timer: u8,
+    sound_timer: u8,
+    variables: [u8; 16],
+    display: Display,
+}
+
+impl State {
+    pub fn new() -> Self {
+        Self {
+            memory: [0; 4096],
+            pc: 0,
+            index: 0,
+            stack: vec![],
+            delay_timer: 0,
+            sound_timer: 0,
+            variables: [0; 16],
+            display: Display::new(),
+        }
+    }
+
+    pub fn default() -> Self {
+        let mut memory = [0u8; 4096];
+        memory[0x50..=0x9F].copy_from_slice(&FONT);
+
+        Self {
+            memory,
+            ..Self::new()
+        }
+    }
+
+    pub fn next_operation(&mut self) -> Operation {
+        let opcode = (self.memory[self.pc] as u16) << 8 + self.memory[self.pc + 1] as u16;
+        self.pc += 2;
+        Operation::new(opcode)
+    }
+
+    pub fn update(&mut self, op: Operation) {
+        match op {
+            _ => (),
+        }
+    }
+}