From f0d0d9abc67766322b7c39531e9c9e430eff8f3f Mon Sep 17 00:00:00 2001
From: scawful <justin.scofield@outlook.com>
Date: Sat, 19 Aug 2023 14:12:45 -0400
Subject: [PATCH] Create SNES skeleton

---
 src/app/emu/snes.cc | 124 ++++++++++++++++++++++++++++++++++++++++++++
 src/app/emu/snes.h  |  73 ++++++++++++++++++++++++++
 2 files changed, 197 insertions(+)
 create mode 100644 src/app/emu/snes.cc
 create mode 100644 src/app/emu/snes.h

diff --git a/src/app/emu/snes.cc b/src/app/emu/snes.cc
new file mode 100644
index 00000000..73945155
--- /dev/null
+++ b/src/app/emu/snes.cc
@@ -0,0 +1,124 @@
+#include "snes.h"
+
+#include <cstdint>
+#include <string>
+
+#include "app/emu/apu.h"
+#include "app/emu/cpu.h"
+#include "app/emu/mem.h"
+#include "app/emu/ppu.h"
+
+namespace yaze {
+namespace app {
+namespace emu {
+
+void SNES::Init(ROM& rom) {
+  // Initialize CPU
+  cpu.Init();
+
+  // Initialize PPU
+  ppu.Init();
+
+  // Initialize APU
+  apu.Init();
+
+  // Load ROM
+  memory_.SetMemory(rom.vector());
+}
+
+void SNES::Run() {
+  running_ = true;
+
+  const int cpuClockSpeed = 21477272;  // 21.477272 MHz
+  const int ppuClockSpeed = 5369318;   // 5.369318 MHz
+  const int apuClockSpeed = 32000;     // 32 KHz
+  const double targetFPS = 60.0;       // 60 frames per second
+
+  const double cpuCycleTime = 1.0 / cpuClockSpeed;
+  const double ppuCycleTime = 1.0 / ppuClockSpeed;
+  const double apuCycleTime = 1.0 / apuClockSpeed;
+  const double frameTime = 1.0 / targetFPS;
+
+  double cpuAccumulatedTime = 0.0;
+  double ppuAccumulatedTime = 0.0;
+  double apuAccumulatedTime = 0.0;
+  double frameAccumulatedTime = 0.0;
+
+  auto lastTime = std::chrono::high_resolution_clock::now();
+
+  while (running_) {
+    auto currentTime = std::chrono::high_resolution_clock::now();
+    double deltaTime =
+        std::chrono::duration<double>(currentTime - lastTime).count();
+    lastTime = currentTime;
+
+    cpuAccumulatedTime += deltaTime;
+    ppuAccumulatedTime += deltaTime;
+    apuAccumulatedTime += deltaTime;
+    frameAccumulatedTime += deltaTime;
+
+    while (cpuAccumulatedTime >= cpuCycleTime) {
+      cpu.ExecuteInstruction(cpu.ReadByte(cpu.PC));
+      cpuAccumulatedTime -= cpuCycleTime;
+    }
+
+    while (ppuAccumulatedTime >= ppuCycleTime) {
+      RenderScanline();
+      ppuAccumulatedTime -= ppuCycleTime;
+    }
+
+    while (apuAccumulatedTime >= apuCycleTime) {
+      // apu.Update();
+      apuAccumulatedTime -= apuCycleTime;
+    }
+
+    if (frameAccumulatedTime >= frameTime) {
+      // renderer.Render();
+      frameAccumulatedTime -= frameTime;
+    }
+
+    HandleInput();
+  }
+}
+
+void SNES::RenderScanline() {
+  // Render background layers
+  for (int layer = 0; layer < 4; layer++) {
+    DrawBackgroundLayer(layer);
+  }
+
+  // Render sprites
+  DrawSprites();
+}
+
+void SNES::DrawBackgroundLayer(int layer) {
+  // ...
+}
+
+void SNES::DrawSprites() {
+  // ...
+}
+
+void SNES::HandleInput() {
+  // ...
+}
+
+void SNES::SaveState(const std::string& path) {
+  // ...
+}
+
+void SNES::LoadState(const std::string& path) {
+  // ...
+}
+
+void SNES::Debug() {
+  // ...
+}
+
+void SNES::Breakpoint(uint16_t address) {
+  // ...
+}
+
+}  // namespace emu
+}  // namespace app
+}  // namespace yaze
\ No newline at end of file
diff --git a/src/app/emu/snes.h b/src/app/emu/snes.h
new file mode 100644
index 00000000..f96db879
--- /dev/null
+++ b/src/app/emu/snes.h
@@ -0,0 +1,73 @@
+#include <cstdint>
+#include <string>
+
+#include "app/emu/apu.h"
+#include "app/emu/cpu.h"
+#include "app/emu/dbg.h"
+#include "app/emu/ppu.h"
+#include "app/rom.h"
+
+namespace yaze {
+namespace app {
+namespace emu {
+
+class SNES {
+ public:
+  SNES()=default;
+  ~SNES()=default;
+
+  // Initialization
+  void Init(ROM& rom);
+
+  // Main emulation loop
+  void Run();
+
+  // Functions for CPU-related operations
+  void Fetch();
+  void Decode();
+  void Execute();
+
+  // Functions for PPU-related operations
+  void RenderScanline();
+  void UpdateSprites();
+  void DrawBackgroundLayer(int layer);
+  void DrawSprites();
+
+  // Memory-related functions
+  uint8_t ReadMemory(uint16_t address);
+  void WriteMemory(uint16_t address, uint8_t value);
+
+  // Controller input handling
+  void HandleInput();
+
+  // Save/Load game state
+  void SaveState(const std::string& path);
+  void LoadState(const std::string& path);
+
+  // Debugger
+  void Debug();
+  void Breakpoint(uint16_t address);
+
+  bool running() const { return running_; }
+
+ private:
+  // Components of the SNES
+  MemoryImpl memory_;
+  CPU cpu{memory_};
+  PPU ppu{memory_};
+  APU apu{memory_};
+
+  // Helper classes
+  Debugger debugger;
+
+  // Other private member variables
+  std::vector<uint8_t> rom_data;
+  bool running_;
+  uint16_t pc;
+  uint32_t cycle;
+  int scanline;
+};
+
+}  // namespace emu
+}  // namespace app
+}  // namespace yaze
\ No newline at end of file