src/apu.rs

@@ -164,7 +164,8 @@ impl Apu {
 
         if self.ctrl.enabled {
             // Frame Sequencer reset to Step 0
-            // TODO: With the current implementation of the frame sequencer, what does this even mean?
+            // TODO: With the current implementation of the frame sequencer,
+            // what does this even mean?
 
             // Square Duty units are reset to first step
             self.ch1.duty_pos = 0;
@@ -180,6 +181,8 @@ impl Apu {
     }
 
     fn reset(&mut self) {
+        // TODO: Clear readable sound registers
+
         self.ch1.sweep = Default::default();
         self.ch1.duty = Default::default();
         self.ch1.envelope = Default::default();
@@ -423,6 +426,7 @@ impl Channel1 {
         }
 
         if self.freq_timer == 0 {
+            // TODO: Why is this 2048?
             self.freq_timer = (2048 - self.frequency()) * 4;
             self.duty_pos = (self.duty_pos + 1) % 8;
         }
@@ -568,6 +572,7 @@ impl Channel2 {
         }
 
         if self.freq_timer == 0 {
+            // TODO: Why is this 2048?
             self.freq_timer = (2048 - self.frequency()) * 4;
             self.duty_pos = (self.duty_pos + 1) % 8;
         }

src/apu/types.rs

@@ -178,7 +178,7 @@ pub(crate) mod ch4 {
         pub struct Frequency(u8);
         impl Debug;
         _initial, _: 7;
-        _length_disable, _: 6;
+        _length_disable, _: 6; // TODO: same as FrequencyHigh, figure out what this is
     }
 
     impl Frequency {
@@ -224,7 +224,7 @@ pub(crate) mod common {
         pub struct FrequencyHigh(u8);
         impl Debug;
         _initial, _: 7;
-        _length_disable, _: 6;
+        _length_disable, _: 6; // TODO: Figure out what the hell this is
         pub freq_bits, set_freq_bits: 2, 0;
     }
 
@@ -342,7 +342,7 @@ pub(crate) mod common {
         pub struct SoundDuty(u8);
         impl Debug;
         from into WavePattern, _wave_pattern, _: 7, 6;
-        _sound_length, _: 5, 0;
+        _sound_length, _: 5, 0; // TODO: Getter only used if bit 6 in NR14 is set
     }
 
     impl SoundDuty {

src/bus.rs

@@ -240,6 +240,7 @@ impl BusIo for Bus {
                     0x49 => self.ppu.monochrome.obj_palette_1.into(),
                     0x4A => self.ppu.pos.window_y,
                     0x4B => self.ppu.pos.window_x,
+                    0x4D => 0xFF, // TODO: CGB Specific Register
                     _ => {
                         eprintln!("Read 0xFF from unused IO register {:#06X}.", addr);
                         0xFF
@@ -311,7 +312,7 @@ impl BusIo for Bus {
                     _ => {}
                 }
             }
-            0xFEA0..=0xFEFF => {} // FIXME: As far as I know, writes to here do nothing.
+            0xFEA0..=0xFEFF => {} // TODO: As far as I know, writes to here do nothing.
             0xFF00..=0xFF7F => {
                 // IO Registers
 

src/cartridge.rs

@@ -114,7 +114,10 @@ impl Cartridge {
     }
 
     fn find_mbc(memory: &[u8]) -> MBCKind {
-        match memory[MBC_TYPE_ADDRESS] {
+        let id = memory[MBC_TYPE_ADDRESS];
+
+        // TODO: Refactor this to match the other enums in this module
+        match id {
             0x00 => MBCKind::None,
             0x01 => MBCKind::MBC1,
             0x02 => MBCKind::MBC1,
@@ -122,7 +125,7 @@ impl Cartridge {
             0x19 => MBCKind::MBC5,
             0x13 => MBCKind::MBC3WithBattery,
             0x11 => MBCKind::MBC3,
-            id => unimplemented!("id {:#04X} is an unsupported MBC", id),
+            _ => unimplemented!("id {:#04X} is an unsupported MBC", id),
         }
     }
 }

src/cpu.rs

@@ -14,6 +14,8 @@ pub struct Cpu {
     reg: Registers,
     flags: Flags,
     ime: ImeState,
+    // TODO: Merge halted and state properties
+    halted: Option<HaltKind>,
     state: State,
 }
 
@@ -43,34 +45,24 @@ impl Cpu {
         })
     }
 
-    pub(crate) fn ime(&self) -> ImeState {
+    pub(crate) fn ime(&self) -> &ImeState {
-        self.ime
+        &self.ime
     }
 
     pub(crate) fn set_ime(&mut self, state: ImeState) {
         self.ime = state;
     }
 
-    pub(crate) fn halt_cpu(&mut self, kind: HaltKind) {
+    pub(crate) fn halt(&mut self, state: HaltKind) {
-        self.state = State::Halt(kind);
+        self.halted = Some(state);
     }
 
-    fn resume_execution(&mut self) {
+    fn resume(&mut self) {
-        self.state = State::Execute;
+        self.halted = None;
     }
 
-    pub(crate) fn is_halted(&self) -> bool {
+    pub(crate) fn halted(&self) -> Option<HaltKind> {
-        match self.state {
+        self.halted
-            State::Halt(_) => true,
-            _ => false,
-        }
-    }
-
-    pub(crate) fn halt_kind(&self) -> Option<HaltKind> {
-        match self.state {
-            State::Halt(kind) => Some(kind),
-            _ => None,
-        }
     }
 
     pub fn load_cartridge(&mut self, path: &str) -> std::io::Result<()> {
@@ -127,7 +119,7 @@ impl Cpu {
             return elapsed;
         }
 
-        if let Some(kind) = self.halt_kind() {
+        if let Some(kind) = self.halted() {
             use HaltKind::*;
 
             self.bus.clock();
@@ -200,7 +192,7 @@ impl Cpu {
         let enable = self.int_enable();
 
         // TODO: Ensure that this behaviour is correct
-        if self.is_halted() {
+        if self.halted.is_some() {
             // When we're here either a HALT with IME set or
             // a HALT with IME not set and No pending Interrupts was called
 
@@ -209,7 +201,7 @@ impl Cpu {
                 // nothing actually needs to be added here. This is just documentation
                 // since it's a bit weird why nothing is being done
 
-                self.resume_execution();
+                self.resume();
             }
         }
 
@@ -272,7 +264,7 @@ impl Cpu {
 #[derive(Debug, Clone, Copy)]
 enum State {
     Execute,
-    Halt(HaltKind),
+    // Halt,
     // Stop,
 }
 

src/instruction.rs

@@ -590,12 +590,12 @@ impl Instruction {
                 // HALT | Enter CPU low power consumption mode until interrupt occurs
                 use HaltKind::*;
 
-                let kind = match cpu.ime() {
+                let kind = match *cpu.ime() {
                     ImeState::Enabled => ImeEnabled,
                     _ if cpu.int_request() & cpu.int_enable() != 0 => SomePending,
                     _ => NonePending,
                 };
-                cpu.halt_cpu(kind);
+                cpu.halt(kind);
                 Cycle::new(4)
             }
             Instruction::ADC(source) => match source {

src/main.rs

@@ -63,16 +63,16 @@ fn main() -> Result<()> {
     };
 
     // Initialize Audio
-    // let spsc: AudioSPSC<f32> = Default::default();
+    let spsc: AudioSPSC<f32> = Default::default();
-    // let (prod, cons) = spsc.init();
+    let (prod, cons) = spsc.init();
-    // let (_stream, stream_handle) = OutputStream::try_default().expect("Initialized Audio");
+    let (_stream, stream_handle) = OutputStream::try_default().expect("Initialized Audio");
-    // let sink = Sink::try_new(&stream_handle)?;
+    let sink = Sink::try_new(&stream_handle)?;
-    // sink.append(cons);
+    sink.append(cons);
-    // game_boy.apu_mut().set_producer(prod);
+    game_boy.apu_mut().set_producer(prod);
 
-    // std::thread::spawn(move || {
+    std::thread::spawn(move || {
-    //     sink.sleep_until_end();
+        sink.sleep_until_end();
-    // });
+    });
 
     let mut start = Instant::now();
     let frame_time = Duration::from_secs_f64(1.0 / 59.73); // 59.73 Hz on Host