src/bus.rs

@@ -13,8 +13,8 @@ pub(crate) const BOOT_SIZE: usize = 0x100;
 #[derive(Debug)]
 pub struct Bus {
     boot: Option<[u8; BOOT_SIZE]>, // Boot ROM is 256b long
-    pub(crate) cart: Option<Cartridge>,
-    pub(crate) ppu: Ppu,
+    cart: Option<Cartridge>,
+    ppu: Ppu,
     work_ram: WorkRam,
     var_ram: VariableWorkRam,
     timer: Timer,
@@ -22,7 +22,7 @@ pub struct Bus {
     apu: Apu,
     high_ram: HighRam,
     serial: Serial,
-    pub(crate) joyp: Joypad,
+    joypad: Joypad,
 }
 
 impl Default for Bus {
@@ -38,7 +38,7 @@ impl Default for Bus {
             apu: Default::default(),
             high_ram: Default::default(),
             serial: Default::default(),
-            joyp: Default::default(),
+            joypad: Default::default(),
         }
     }
 }
@@ -86,10 +86,30 @@ impl Bus {
         }
     }
 
+    #[inline]
+    pub(crate) fn joyp_mut(&mut self) -> &mut Joypad {
+        &mut self.joypad
+    }
+
+    #[inline]
+    pub(crate) fn cart(&self) -> Option<&Cartridge> {
+        self.cart.as_ref()
+    }
+
+    #[inline]
+    pub(crate) fn cart_mut(&mut self) -> Option<&mut Cartridge> {
+        self.cart.as_mut()
+    }
+
     #[inline]
     pub(crate) fn apu_mut(&mut self) -> &mut Apu {
         &mut self.apu
     }
+
+    #[inline]
+    pub fn ppu(&self) -> &Ppu {
+        &self.ppu
+    }
 }
 
 impl Bus {
@@ -219,7 +239,7 @@ impl BusIo for Bus {
                 // Every address here starts with 0xFF so we can just check the
                 // low byte to figure out which register it is
                 match addr & 0x00FF {
-                    0x00 => self.joyp.p1,
+                    0x00 => self.joypad.p1,
                     0x01 => self.serial.next,
                     0x02 => self.serial.ctrl.into(),
                     0x04 => (self.timer.divider >> 8) as u8,
@@ -317,7 +337,7 @@ impl BusIo for Bus {
                 // Every address here starts with 0xFF so we can just check the
                 // low byte to figure out which register it is
                 match addr & 0x00FF {
-                    0x00 => self.joyp.update(byte),
+                    0x00 => self.joypad.update(byte),
                     0x01 => self.serial.next = byte,
                     0x02 => self.serial.ctrl = byte.into(),
                     0x04 => self.timer.divider = 0x0000,
@@ -381,7 +401,7 @@ impl Bus {
         let lcd_stat = self.ppu.int.lcd_stat();
 
         // Read the current interrupt information from the Joypad
-        let joypad = self.joyp.interrupt();
+        let joypad = self.joypad.interrupt();
 
         // Read the current interrupt information from the Timer
         let timer = self.timer.interrupt();
@@ -411,7 +431,7 @@ impl Bus {
         self.ppu.int.set_lcd_stat(lcd_stat);
 
         // Update the Joypad's instance of the following interrupts
-        self.joyp.set_interrupt(joypad);
+        self.joypad.set_interrupt(joypad);
 
         // Update the Timer's instance of the following interrupts
         self.timer.set_interrupt(timer);

src/cpu.rs

@@ -151,6 +151,16 @@ impl BusIo for Cpu {
 }
 
 impl Cpu {
+    #[inline]
+    pub(crate) fn bus(&self) -> &Bus {
+        &self.bus
+    }
+
+    #[inline]
+    pub(crate) fn bus_mut(&mut self) -> &mut Bus {
+        &mut self.bus
+    }
+
     fn handle_ei(&mut self) {
         match self.ime {
             ImeState::EiExecuted => self.ime = ImeState::Pending,

src/emu.rs

@@ -1,6 +1,7 @@
 use crate::apu::gen::SampleProducer;
 use crate::bus::BOOT_SIZE;
 use crate::cpu::Cpu;
+use crate::joypad::{self, Joypad};
 use crate::{Cycle, GB_HEIGHT, GB_WIDTH};
 use clap::crate_name;
 use gilrs::Gilrs;
@@ -19,9 +20,9 @@ pub fn run_frame(emu: &mut Emulator, gamepad: &mut Gilrs, key: &WinitInputHelper
     let mut elapsed = 0;
 
     if let Some(event) = gamepad.next_event() {
-        crate::joypad::handle_gamepad_input(&mut emu.cpu.bus.joyp, event);
+        joypad::handle_gamepad_input(emu.joyp_mut(), event);
     }
-    crate::joypad::handle_keyboard_input(&mut emu.cpu.bus.joyp, key);
+    joypad::handle_keyboard_input(emu.joyp_mut(), key);
 
     while elapsed < CYCLES_IN_FRAME {
         elapsed += emu.step();
@@ -31,7 +32,7 @@ pub fn run_frame(emu: &mut Emulator, gamepad: &mut Gilrs, key: &WinitInputHelper
 }
 
 pub fn draw_frame(emu: &Emulator, buf: &mut [u8; GB_HEIGHT * GB_WIDTH * 4]) {
-    buf.copy_from_slice(emu.cpu.bus.ppu.frame_buf.as_ref());
+    buf.copy_from_slice(emu.cpu.bus().ppu().frame_buf());
 }
 
 pub struct Emulator {
@@ -80,20 +81,25 @@ impl Emulator {
     }
 
     fn load_rom(&mut self, rom: Vec<u8>) {
-        self.cpu.bus.load_cart(rom);
+        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.apu_mut().attach_producer(prod)
+        self.cpu.bus_mut().apu_mut().attach_producer(prod)
     }
 
     pub fn title(&self) -> &str {
-        self.cpu.bus.cart_title().unwrap_or(DEFAULT_TITLE)
+        self.cpu.bus().cart_title().unwrap_or(DEFAULT_TITLE)
     }
 
     pub fn try_write_sav(&self) -> std::io::Result<()> {
-        if let Some(ext_ram) = self.cpu.bus.cart.as_ref().map(|c| c.ext_ram()).flatten() {
-            if let Some(title) = self.cpu.bus.cart_title() {
+        if let Some(ext_ram) = self.cpu.bus().cart().map(|c| c.ext_ram()).flatten() {
+            if let Some(title) = self.cpu.bus().cart_title() {
                 let mut save_path = Self::data_path().unwrap_or_else(|| PathBuf::from("."));
                 save_path.push(title);
                 save_path.set_extension("sav");
@@ -107,7 +113,7 @@ impl Emulator {
     }
 
     pub fn try_load_sav(&mut self) -> std::io::Result<()> {
-        if let Some(cart) = &mut self.cpu.bus.cart {
+        if let Some(cart) = self.cpu.bus_mut().cart_mut() {
             if let Some(title) = cart.title() {
                 let mut save_path = Self::data_path().unwrap_or_else(|| PathBuf::from("."));
                 save_path.push(title);

src/ppu.rs

@@ -48,7 +48,7 @@ pub struct Ppu {
     fetch: PixelFetcher,
     fifo: PixelFifo,
     obj_buffer: ObjectBuffer,
-    pub(crate) frame_buf: Box<[u8; GB_WIDTH * GB_HEIGHT * 4]>,
+    frame_buf: Box<[u8; GB_WIDTH * GB_HEIGHT * 4]>,
     win_stat: WindowStatus,
 
     scanline_start: bool,
@@ -423,6 +423,11 @@ impl Ppu {
         self.frame_buf.swap_with_slice(&mut blank);
     }
 
+    #[inline]
+    pub(crate) fn frame_buf(&self) -> &[u8; GB_HEIGHT * GB_WIDTH * 4] {
+        &self.frame_buf
+    }
+
     fn clock_fifo(&mut self) -> Option<GrayShade> {
         use RenderPriority::*;