src/bus.rs

@@ -7,13 +7,14 @@ use crate::ppu::{Ppu, PpuMode};
 use crate::serial::Serial;
 use crate::timer::Timer;
 use crate::work_ram::{VariableWorkRam, WorkRam};
+use std::{fs::File, io::Read};
 
-pub(crate) const BOOT_SIZE: usize = 0x100;
+const BOOT_ROM_SIZE: usize = 0x100;
 
 #[derive(Debug)]
 pub struct Bus {
-    boot: Option<[u8; BOOT_SIZE]>, // Boot ROM is 256b long
+    boot: Option<[u8; BOOT_ROM_SIZE]>, // Boot ROM is 256b long
-    cart: Option<Cartridge>,
+    cartridge: Option<Cartridge>,
     pub(crate) ppu: Ppu,
     work_ram: WorkRam,
     var_ram: VariableWorkRam,
@@ -29,7 +30,7 @@ impl Default for Bus {
     fn default() -> Self {
         Self {
             boot: None,
-            cart: None,
+            cartridge: None,
             ppu: Default::default(),
             work_ram: Default::default(),
             var_ram: Default::default(),
@@ -44,19 +45,25 @@ impl Default for Bus {
 }
 
 impl Bus {
-    pub(crate) fn with_boot(rom: [u8; 256]) -> Self {
+    pub(crate) fn with_boot(path: &str) -> anyhow::Result<Self> {
-        Self {
+        let mut file = File::open(path)?;
-            boot: Some(rom),
+        let mut boot_rom = [0u8; 256];
+
+        file.read_exact(&mut boot_rom)?;
+
+        Ok(Self {
+            boot: Some(boot_rom),
             ..Default::default()
-        }
+        })
     }
 
-    pub(crate) fn load_cart(&mut self, rom: Vec<u8>) {
+    pub(crate) fn load_cartridge(&mut self, path: &str) -> std::io::Result<()> {
-        self.cart = Some(Cartridge::new(rom));
+        self.cartridge = Some(Cartridge::new(path)?);
+        Ok(())
     }
 
-    pub(crate) fn cart_title(&self) -> Option<&str> {
+    pub(crate) fn rom_title(&self) -> Option<&str> {
-        self.cart.as_ref()?.title()
+        self.cartridge.as_ref()?.title()
     }
 
     #[allow(dead_code)]
@@ -64,12 +71,10 @@ impl Bus {
         self.boot.is_some()
     }
 
-    #[inline]
     pub(crate) fn clock(&mut self) {
         self.tick(4);
     }
 
-    #[inline]
     fn tick(&mut self, limit: u8) {
         for _ in 0..limit {
             self.timer.tick();
@@ -85,11 +90,6 @@ impl Bus {
             self.oam_write_byte(dest_addr, byte);
         }
     }
-
-    #[inline]
-    pub(crate) fn joyp_mut(&mut self) -> &mut Joypad {
-        &mut self.joypad
-    }
 }
 
 impl Bus {
@@ -104,13 +104,13 @@ impl Bus {
                     }
                 }
 
-                match self.cart.as_ref() {
+                match self.cartridge.as_ref() {
                     Some(cart) => cart.read_byte(addr),
                     None => panic!("Tried to read from a non-existent cartridge"),
                 }
             }
             0x8000..=0x9FFF => self.ppu.read_byte(addr), // 8KB Video RAM
-            0xA000..=0xBFFF => match self.cart.as_ref() {
+            0xA000..=0xBFFF => match self.cartridge.as_ref() {
                 // 8KB External RAM
                 Some(cart) => cart.read_byte(addr),
                 None => panic!("Tried to read from a non-existent cartridge"),
@@ -157,7 +157,7 @@ impl BusIo for Bus {
                     }
                 }
 
-                match self.cart.as_ref() {
+                match self.cartridge.as_ref() {
                     Some(cart) => cart.read_byte(addr),
                     None => panic!("Tried to read from a non-existent cartridge"),
                 }
@@ -169,7 +169,7 @@ impl BusIo for Bus {
                     _ => self.ppu.read_byte(addr),
                 }
             }
-            0xA000..=0xBFFF => match self.cart.as_ref() {
+            0xA000..=0xBFFF => match self.cartridge.as_ref() {
                 // 8KB External RAM
                 Some(cart) => cart.read_byte(addr),
                 None => panic!("Tried to read from a non-existent cartridge"),
@@ -262,7 +262,7 @@ impl BusIo for Bus {
             0x0000..=0x7FFF => {
                 // 16KB ROM bank 00 (ends at 0x3FFF)
                 // and 16KB ROM Bank 01 -> NN (switchable via MB)
-                match self.cart.as_mut() {
+                match self.cartridge.as_mut() {
                     Some(cart) => cart.write_byte(addr, byte),
                     None => panic!("Tried to write into non-existent cartridge"),
                 }
@@ -276,7 +276,7 @@ impl BusIo for Bus {
             }
             0xA000..=0xBFFF => {
                 // 8KB External RAM
-                match self.cart.as_mut() {
+                match self.cartridge.as_mut() {
                     Some(cart) => cart.write_byte(addr, byte),
                     None => panic!("Tried to write into non-existent cartridge"),
                 }

src/cartridge.rs

@@ -1,3 +1,7 @@
+use std::fs::File;
+use std::io::{self, Read};
+use std::path::Path;
+
 use crate::bus::BusIo;
 
 const RAM_SIZE_ADDRESS: usize = 0x0149;
@@ -13,15 +17,19 @@ pub(crate) struct Cartridge {
 }
 
 impl Cartridge {
-    pub(crate) fn new(memory: Vec<u8>) -> Self {
+    pub(crate) fn new<P: AsRef<Path> + ?Sized>(path: &P) -> io::Result<Self> {
+        let mut memory = vec![];
+        let mut rom = File::open(path)?;
+        rom.read_to_end(&mut memory)?;
+
         let title = Self::find_title(&memory);
         eprintln!("Cartridge Title: {:?}", title);
 
-        Self {
+        Ok(Self {
             mbc: Self::detect_mbc(&memory),
             title,
             memory,
-        }
+        })
     }
 
     fn detect_mbc(memory: &[u8]) -> Box<dyn MBCIo> {

src/cpu.rs

@@ -1,6 +1,9 @@
-use crate::bus::{Bus, BusIo, BOOT_SIZE};
+use crate::apu::Apu;
+use crate::bus::{Bus, BusIo};
 use crate::instruction::Instruction;
 use crate::interrupt::{InterruptEnable, InterruptFlag};
+use crate::joypad::Joypad;
+use crate::ppu::Ppu;
 use crate::Cycle;
 use bitfield::bitfield;
 use std::fmt::{Display, Formatter, Result as FmtResult};
@@ -15,7 +18,7 @@ pub struct Cpu {
 }
 
 impl Cpu {
-    pub(crate) fn without_boot() -> Self {
+    pub fn new() -> Self {
         Self {
             reg: Registers {
                 a: 0x01,
@@ -33,11 +36,11 @@ impl Cpu {
         }
     }
 
-    pub(crate) fn with_boot(rom: [u8; BOOT_SIZE]) -> Self {
+    pub fn boot_new(path: &str) -> anyhow::Result<Self> {
-        Self {
+        Ok(Self {
-            bus: Bus::with_boot(rom),
+            bus: Bus::with_boot(path)?,
             ..Default::default()
-        }
+        })
     }
 
     pub(crate) fn ime(&self) -> ImeState {
@@ -69,6 +72,14 @@ impl Cpu {
             _ => None,
         }
     }
+
+    pub fn load_cartridge(&mut self, path: &str) -> std::io::Result<()> {
+        self.bus.load_cartridge(path)
+    }
+
+    pub fn rom_title(&self) -> Option<&str> {
+        self.bus.rom_title()
+    }
 }
 
 impl Cpu {
@@ -156,14 +167,16 @@ impl BusIo for Cpu {
 }
 
 impl Cpu {
-    #[inline]
+    pub fn ppu(&mut self) -> &Ppu {
-    pub(crate) fn bus(&self) -> &Bus {
+        &self.bus.ppu
-        &self.bus
     }
 
-    #[inline]
+    pub fn apu_mut(&mut self) -> &mut Apu {
-    pub(crate) fn bus_mut(&mut self) -> &mut Bus {
+        &mut self.bus.apu
-        &mut self.bus
+    }
+
+    pub(crate) fn joypad_mut(&mut self) -> &mut Joypad {
+        &mut self.bus.joypad
     }
 
     fn handle_ei(&mut self) {

src/emu.rs

@@ -1,7 +1,8 @@
-use crate::apu::gen::SampleProducer;
+use crate::cpu::Cpu as SM83;
-use crate::cpu::Cpu;
+use crate::joypad;
-use crate::joypad::{self, Joypad};
+use crate::ppu::Ppu;
-use crate::{Cycle, GB_HEIGHT, GB_WIDTH};
+use crate::Cycle;
+use anyhow::Result;
 use gilrs::Gilrs;
 use std::time::Duration;
 use winit_input_helper::WinitInputHelper;
@@ -11,114 +12,56 @@ pub const CYCLES_IN_FRAME: Cycle = 456 * 154; // 456 Cycles times 154 scanlines
 pub(crate) const SM83_CLOCK_SPEED: u64 = 0x40_0000; // Hz which is 4.194304Mhz
 const DEFAULT_TITLE: &str = "DMG-01 Emulator";
 
-pub fn run_frame(emu: &mut Emulator, gamepad: &mut Gilrs, key: &WinitInputHelper) -> Cycle {
+pub fn init(boot_path: Option<&str>, rom_path: &str) -> Result<SM83> {
+    let mut cpu = match boot_path {
+        Some(path) => SM83::boot_new(path)?,
+        None => SM83::new(),
+    };
+
+    eprintln!("Initialized GB Emulator");
+
+    cpu.load_cartridge(rom_path)?;
+    Ok(cpu)
+}
+
+pub fn rom_title(game_boy: &SM83) -> &str {
+    game_boy.rom_title().unwrap_or(DEFAULT_TITLE)
+}
+
+pub fn run(
+    game_boy: &mut SM83,
+    gamepad: &mut Gilrs,
+    input: &WinitInputHelper,
+    target: Cycle,
+) -> Cycle {
     let mut elapsed = 0;
 
     if let Some(event) = gamepad.next_event() {
-        joypad::handle_gamepad_input(emu.joyp_mut(), event);
+        joypad::handle_gamepad_input(game_boy.joypad_mut(), event);
     }
-    joypad::handle_keyboard_input(emu.joyp_mut(), key);
+    joypad::handle_keyboard_input(game_boy.joypad_mut(), input);
 
-    while elapsed < CYCLES_IN_FRAME {
+    while elapsed < target {
-        elapsed += emu.step();
+        elapsed += game_boy.step();
     }
 
     elapsed
 }
 
-pub fn draw_frame(emu: &Emulator, buf: &mut [u8; GB_HEIGHT * GB_WIDTH * 4]) {
+pub fn run_frame(game_boy: &mut SM83, gamepad: &mut Gilrs, input: &WinitInputHelper) -> Cycle {
-    buf.copy_from_slice(emu.cpu.bus().ppu.frame_buf());
+    let mut elapsed = 0;
+
+    if let Some(event) = gamepad.next_event() {
+        joypad::handle_gamepad_input(game_boy.joypad_mut(), event);
+    }
+    joypad::handle_keyboard_input(game_boy.joypad_mut(), input);
+    while elapsed < CYCLES_IN_FRAME {
+        elapsed += game_boy.step();
+    }
+
+    elapsed
 }
 
-pub struct Emulator {
+pub fn draw(ppu: &Ppu, frame: &mut [u8]) {
-    cpu: Cpu,
+    ppu.copy_to_gui(frame);
-    timestamp: Cycle,
-}
-
-impl Emulator {
-    fn new(cpu: Cpu) -> Self {
-        Self {
-            cpu,
-            timestamp: Default::default(),
-        }
-    }
-
-    fn step(&mut self) -> Cycle {
-        let cycles = self.cpu.step();
-        self.timestamp += cycles;
-        cycles
-    }
-
-    fn load_cart(&mut self, rom: Vec<u8>) {
-        self.cpu.bus_mut().load_cart(rom)
-    }
-
-    #[inline]
-    fn joyp_mut(&mut self) -> &mut Joypad {
-        self.cpu.bus_mut().joyp_mut()
-    }
-
-    pub fn set_prod(&mut self, prod: SampleProducer<f32>) {
-        self.cpu.bus_mut().apu.attach_producer(prod)
-    }
-
-    pub fn title(&self) -> &str {
-        self.cpu.bus().cart_title().unwrap_or(DEFAULT_TITLE)
-    }
-}
-
-pub mod build {
-    use std::fs::File;
-    use std::io::{Read, Result};
-    use std::path::Path;
-
-    use crate::bus::BOOT_SIZE;
-    use crate::cpu::Cpu;
-
-    use super::Emulator;
-
-    #[derive(Debug, Default)]
-    pub struct EmulatorBuilder {
-        boot: Option<[u8; BOOT_SIZE]>,
-        cart: Option<Vec<u8>>,
-    }
-
-    impl EmulatorBuilder {
-        pub fn new() -> Self {
-            Default::default()
-        }
-
-        pub fn with_boot<P: AsRef<Path>>(mut self, path: P) -> Result<Self> {
-            let mut file = File::open(path.as_ref())?;
-
-            let mut buf = [0x00; BOOT_SIZE];
-            file.read_exact(&mut buf)?;
-
-            self.boot = Some(buf);
-            Ok(self)
-        }
-
-        pub fn with_cart<P: AsRef<Path>>(mut self, path: P) -> Result<Self> {
-            let mut file = File::open(path.as_ref())?;
-
-            let mut buf = Vec::new();
-            file.read_to_end(&mut buf)?;
-
-            self.cart = Some(buf);
-            Ok(self)
-        }
-
-        pub fn finish(mut self) -> Emulator {
-            let mut emu = Emulator::new(match self.boot {
-                Some(rom) => Cpu::with_boot(rom),
-                None => Cpu::without_boot(),
-            });
-
-            if let Some(rom) = self.cart.take() {
-                emu.load_cart(rom)
-            }
-
-            emu
-        }
-    }
 }

src/joypad.rs

@@ -110,7 +110,6 @@ impl ButtonEvent {
     }
 }
 
-#[inline]
 pub fn handle_keyboard_input(pad: &mut Joypad, input: &WinitInputHelper) {
     use winit::event::VirtualKeyCode;
 
@@ -176,7 +175,6 @@ pub fn handle_keyboard_input(pad: &mut Joypad, input: &WinitInputHelper) {
     }
 }
 
-#[inline]
 pub fn handle_gamepad_input(pad: &mut Joypad, event: GamepadEvent) {
     use Button::*;
     use GamepadEventType::*;

src/main.rs

@@ -1,8 +1,5 @@
-use std::convert::TryInto;
-
 use anyhow::{anyhow, Result};
 use clap::{crate_authors, crate_description, crate_name, crate_version, App, Arg};
-use gb::emu::build::EmulatorBuilder;
 use gb::{AudioSPSC, Cycle, GB_HEIGHT, GB_WIDTH};
 use gilrs::Gilrs;
 use pixels::{PixelsBuilder, SurfaceTexture};
@@ -14,7 +11,7 @@ use winit::window::{Window, WindowBuilder};
 use winit_input_helper::WinitInputHelper;
 
 const WINDOW_SCALE: usize = 3;
-const AUDIO_ENABLED: bool = true;
+const AUDIO_ENABLED: bool = false;
 
 fn main() -> Result<()> {
     let app = App::new(crate_name!())
@@ -41,15 +38,13 @@ fn main() -> Result<()> {
         )
         .get_matches();
 
-    let mut emu_build =
+    let rom_path = m
-        EmulatorBuilder::new().with_cart(m.value_of("rom").expect("ROM path provided"))?;
+        .value_of("rom")
+        .expect("Required value 'rom' was provided");
 
-    if let Some(path) = m.value_of("boot") {
+    let mut game_boy =
-        emu_build = emu_build.with_boot(path)?;
+        gb::emu::init(m.value_of("boot"), rom_path).expect("Initialize DMG-01 Emulator");
-    }
+    let rom_title = gb::emu::rom_title(&game_boy);
-
-    let mut emu = emu_build.finish();
-    let rom_title = emu.title();
 
     let mut gamepad = Gilrs::new().expect("Initialize Controller Support");
 
@@ -73,14 +68,10 @@ fn main() -> Result<()> {
     if AUDIO_ENABLED {
         let spsc: AudioSPSC<f32> = Default::default();
         let (prod, cons) = spsc.init();
-        let sink = {
+        let sink = Sink::try_new(&stream_handle)?;
-            let s = Sink::try_new(&stream_handle)?;
+        sink.append(cons);
-            s.append(cons);
+        sink.set_volume(0.1); // TODO: Is this the right way to go about this?
-            s.set_volume(0.1);
+        game_boy.apu_mut().attach_producer(prod);
-            s
-        };
-
-        emu.set_prod(prod);
 
         std::thread::spawn(move || {
             sink.sleep_until_end();
@@ -111,17 +102,12 @@ fn main() -> Result<()> {
                 pixels.resize_surface(size.width, size.height);
             }
 
-            cycle_count += gb::emu::run_frame(&mut emu, &mut gamepad, &input);
+            cycle_count += gb::emu::run_frame(&mut game_boy, &mut gamepad, &input);
 
             if cycle_count >= gb::emu::CYCLES_IN_FRAME {
                 cycle_count %= gb::emu::CYCLES_IN_FRAME;
 
-                let buf: &mut [u8; GB_WIDTH * GB_HEIGHT * 4] = pixels
+                gb::emu::draw(game_boy.ppu(), pixels.get_frame());
-                    .get_frame()
-                    .try_into()
-                    .expect("Size of Pixel Buffer is GB_WIDTH * GB_HEIGHT * 4");
-
-                gb::emu::draw_frame(&emu, buf);
                 window.request_redraw();
             }
         }

src/ppu.rs

@@ -418,8 +418,8 @@ impl Ppu {
         self.frame_buf.swap_with_slice(&mut blank);
     }
 
-    pub(crate) fn frame_buf(&self) -> &[u8; GB_HEIGHT * GB_WIDTH * 4] {
+    pub fn copy_to_gui(&self, frame: &mut [u8]) {
-        &self.frame_buf
+        frame.copy_from_slice(self.frame_buf.as_ref());
     }
 
     fn clock_fifo(&mut self) -> Option<GrayShade> {
@@ -629,7 +629,6 @@ impl ObjectBuffer {
         self.len += 1;
     }
 
-    #[inline]
     fn iter_mut(&mut self) -> std::slice::IterMut<'_, Option<ObjectAttribute>> {
         self.inner.iter_mut()
     }