feat: stub sound register 0xff26

src/bus.rs

@@ -1,6 +1,7 @@
 use super::cartridge::Cartridge;
 use super::interrupt::Interrupt;
 use super::ppu::PPU;
+use super::sound::Sound;
 use super::timer::Timer;
 use super::work_ram::{VariableWorkRAM, WorkRAM};
 
@@ -13,6 +14,7 @@ pub struct Bus {
     vwram: VariableWorkRAM,
     timer: Timer,
     interrupt: Interrupt,
+    sound: Sound,
 }
 
 impl Default for Bus {
@@ -25,6 +27,7 @@ impl Default for Bus {
             vwram: Default::default(),
             timer: Default::default(),
             interrupt: Default::default(),
+            sound: Default::default(),
         }
     }
 }
@@ -96,6 +99,7 @@ impl Bus {
                 match addr {
                     0xFF07 => self.timer.control.into(),
                     0xFF0F => self.interrupt.flag.into(),
+                    0xFF26 => self.sound.status.into(),
                     _ => unimplemented!("Unable to read {:#06X} in I/O Registers", addr),
                 }
             }
@@ -153,6 +157,7 @@ impl Bus {
                 match addr {
                     0xFF07 => self.timer.control = byte.into(),
                     0xFF0F => self.interrupt.flag = byte.into(),
+                    0xFF26 => self.sound.status = byte.into(), // FIXME: Should we control which bytes are written to here?
                     _ => unimplemented!("Unable to write to {:#06X} in I/O Registers", addr),
                 };
             }

src/lib.rs

@@ -4,5 +4,6 @@ pub mod cpu;
 mod instruction;
 mod interrupt;
 mod ppu;
+mod sound;
 mod timer;
 mod work_ram;

src/main.rs

@@ -1,7 +1,7 @@
 use gb::cpu::Cpu as LR35902;
 
 fn main() {
-    let mut game_boy = LR35902::new_without_boot();
+    let mut game_boy = LR35902::new();
 
     game_boy.load_cartridge("bin/cpu_instrs.gb");
 

src/sound.rs

@@ -0,0 +1,35 @@
+#[derive(Debug, Clone, Copy, Default)]
+pub struct Sound {
+    pub status: SoundStatus,
+}
+
+#[derive(Debug, Clone, Copy, Default)]
+pub struct SoundStatus {
+    pub all_enabled: bool, // You can actually write to this one.
+    sound_4: bool,
+    sound_3: bool,
+    sound_2: bool,
+    sound_1: bool,
+}
+
+impl From<u8> for SoundStatus {
+    fn from(byte: u8) -> Self {
+        Self {
+            all_enabled: (byte >> 7) & 0x01 == 0x01,
+            sound_4: (byte >> 3) & 0x01 == 0x01,
+            sound_3: (byte >> 2) & 0x01 == 0x01,
+            sound_2: (byte >> 1) & 0x01 == 0x01,
+            sound_1: (byte >> 0) & 0x01 == 0x01,
+        }
+    }
+}
+
+impl From<SoundStatus> for u8 {
+    fn from(status: SoundStatus) -> Self {
+        (status.all_enabled as u8) << 7
+            | (status.sound_4 as u8) << 3
+            | (status.sound_3 as u8) << 2
+            | (status.sound_2 as u8) << 1
+            | (status.sound_1 as u8) << 0
+    }
+}