Refactor Snes class and enhance Apu functionality

- Updated Snes constructor to initialize CPU callbacks directly, improving readability and maintainability.
- Removed unnecessary CpuCallbacks parameter from Cpu constructor, streamlining the class design.
- Added new methods in Apu for retrieving cycles, status, control, and handling DMA transfers, enhancing audio processing capabilities.
- Introduced unit tests for Apu to validate initialization, sample generation, and handshake timing, ensuring robust audio functionality.

src/app/emu/audio/apu.h

@@ -65,6 +65,18 @@ class Apu {
   auto dsp() -> Dsp & { return dsp_; }
   auto spc700() -> Spc700 & { return spc700_; }
 
+  uint64_t GetCycles() const { return cycles_; }
+  uint8_t GetStatus() const { return ram[0x00]; }
+  uint8_t GetControl() const { return ram[0x01]; }
+  void GetSamples(int16_t *buffer, int count, bool loop = false) {
+    dsp_.GetSamples(buffer, count, loop);
+  }
+  void WriteDma(uint16_t address, const uint8_t *data, int count) {
+    for (int i = 0; i < count; i++) {
+      ram[address + i] = data[i];
+    }
+  }
+
   // Port buffers (equivalent to $2140 to $2143 for the main CPU)
   std::array<uint8_t, 6> in_ports_;  // includes 2 bytes of ram
   std::array<uint8_t, 4> out_ports_;

src/app/emu/cpu/cpu.h

@@ -31,10 +31,12 @@ class InstructionEntry {
 
 class Cpu {
  public:
-  explicit Cpu(Memory& mem, CpuCallbacks& callbacks)
-      : memory(mem), callbacks_(callbacks) {}
+  explicit Cpu(Memory& mem) : memory(mem) {}
   void Reset(bool hard = false);
 
+  auto& callbacks() { return callbacks_; }
+  const auto& callbacks() const { return callbacks_; }
+
   void RunOpcode();
 
   void ExecuteInstruction(uint8_t opcode);
@@ -781,8 +783,8 @@ class Cpu {
   bool int_wanted_ = false;
   bool int_delay_ = false;
 
-  CpuCallbacks callbacks_;
   Memory& memory;
+  CpuCallbacks callbacks_;
 };
 
 }  // namespace emu

src/app/emu/snes.h

@@ -2,6 +2,8 @@
 #define YAZE_APP_EMU_SNES_H
 
 #include <cstdint>
+#include <functional>
+#include <memory>
 
 #include "app/emu/audio/apu.h"
 #include "app/emu/cpu/cpu.h"
@@ -21,7 +23,11 @@ struct Input {
 
 class Snes {
  public:
-  Snes() = default;
+  Snes() {
+    cpu_.callbacks().read_byte = [this](uint32_t adr) { return CpuRead(adr); };
+    cpu_.callbacks().write_byte = [this](uint32_t adr, uint8_t val) { CpuWrite(adr, val); };
+    cpu_.callbacks().idle = [this](bool waiting) { CpuIdle(waiting); };
+  }
   ~Snes() = default;
 
   void Init(std::vector<uint8_t>& rom_data);
@@ -61,14 +67,11 @@ class Snes {
   auto get_ram() -> uint8_t* { return ram; }
   auto mutable_cycles() -> uint64_t& { return cycles_; }
 
+  bool fast_mem_ = false;
+
  private:
   MemoryImpl memory_;
-  CpuCallbacks cpu_callbacks_ = {
-      [&](uint32_t adr) { return CpuRead(adr); },
-      [&](uint32_t adr, uint8_t val) { CpuWrite(adr, val); },
-      [&](bool waiting) { CpuIdle(waiting); },
-  };
-  Cpu cpu_{memory_, cpu_callbacks_};
+  Cpu cpu_{memory_};
   Ppu ppu_{memory_};
   Apu apu_{memory_};
 
@@ -111,12 +114,9 @@ class Snes {
   bool auto_joy_read_ = false;
   uint16_t auto_joy_timer_ = 0;
   bool ppu_latch_;
-
-  bool fast_mem_ = false;
 };
 
 }  // namespace emu
-
 }  // namespace yaze
 
 #endif  // YAZE_APP_EMU_SNES_H