Add step mode to snes emulator

src/app/emu/emulator.cc

@@ -35,19 +35,16 @@ using ImGui::Text;
 void Emulator::Run() {
   if (!snes_.running() && rom()->isLoaded()) {
     snes_.SetupMemory(*rom());
-  }
-
-  // Setup and initialize memory
-  if (loading_ && !running_) {
     snes_.Init(*rom());
-    running_ = true;
   }
 
   RenderNavBar();
 
   if (running_) {
     HandleEvents();
-    snes_.Run();
+    if (!step_) {
+      snes_.Run();
+    }
   }
 
   RenderEmulator();
@@ -69,7 +66,7 @@ void Emulator::RenderNavBar() {
   if (ImGui::IsItemHovered()) {
     ImGui::SetTooltip("Start Emulation");
   }
-  ImGui::SameLine();
+  SameLine();
 
   if (ImGui::Button(ICON_MD_PAUSE)) {
     snes_.SetCpuMode(1);
@@ -77,15 +74,16 @@ void Emulator::RenderNavBar() {
   if (ImGui::IsItemHovered()) {
     ImGui::SetTooltip("Pause Emulation");
   }
-  ImGui::SameLine();
+  SameLine();
 
   if (ImGui::Button(ICON_MD_SKIP_NEXT)) {
     // Step through Code logic
+    snes_.StepRun();
   }
   if (ImGui::IsItemHovered()) {
     ImGui::SetTooltip("Step Through Code");
   }
-  ImGui::SameLine();
+  SameLine();
 
   if (ImGui::Button(ICON_MD_REFRESH)) {
     // Reset Emulator logic
@@ -93,7 +91,7 @@ void Emulator::RenderNavBar() {
   if (ImGui::IsItemHovered()) {
     ImGui::SetTooltip("Reset Emulator");
   }
-  ImGui::SameLine();
+  SameLine();
 
   if (ImGui::Button(ICON_MD_STOP)) {
     // Stop Emulation logic
@@ -102,7 +100,7 @@ void Emulator::RenderNavBar() {
   if (ImGui::IsItemHovered()) {
     ImGui::SetTooltip("Stop Emulation");
   }
-  ImGui::SameLine();
+  SameLine();
 
   if (ImGui::Button(ICON_MD_SAVE)) {
     // Save State logic
@@ -110,7 +108,7 @@ void Emulator::RenderNavBar() {
   if (ImGui::IsItemHovered()) {
     ImGui::SetTooltip("Save State");
   }
-  ImGui::SameLine();
+  SameLine();
 
   if (ImGui::Button(ICON_MD_SYSTEM_UPDATE_ALT)) {
   }
@@ -119,7 +117,7 @@ void Emulator::RenderNavBar() {
   }
 
   // Additional elements
-  ImGui::SameLine();
+  SameLine();
   if (ImGui::Button(ICON_MD_SETTINGS)) {
     // Settings logic
   }
@@ -127,7 +125,7 @@ void Emulator::RenderNavBar() {
     ImGui::SetTooltip("Settings");
   }
 
-  ImGui::SameLine();
+  SameLine();
   if (ImGui::Button(ICON_MD_INFO)) {
     if (ImGui::IsItemHovered()) {
       ImGui::SetTooltip("About Debugger");
@@ -136,7 +134,7 @@ void Emulator::RenderNavBar() {
   }
   static bool show_memory_viewer = false;
 
-  ImGui::SameLine();
+  SameLine();
   if (ImGui::Button(ICON_MD_MEMORY)) {
     show_memory_viewer = !show_memory_viewer;
   }
@@ -329,7 +327,7 @@ void Emulator::RenderMemoryViewer() {
             mem_edit.GotoAddrAndHighlight(static_cast<ImU64>(bookmark.value),
                                           1);
           }
-          ImGui::SameLine();
+          SameLine();
           if (ImGui::Button("Delete")) {
             // Logic to delete the bookmark
             bookmarks.erase(std::remove_if(bookmarks.begin(), bookmarks.end(),
@@ -358,7 +356,7 @@ void Emulator::RenderCpuInstructionLog(
     // Filtering options
     static char filterBuf[256];
     ImGui::InputText("Filter", filterBuf, IM_ARRAYSIZE(filterBuf));
-    ImGui::SameLine();
+    SameLine();
     if (ImGui::Button("Clear")) { /* Clear filter logic */
     }
 
@@ -367,9 +365,8 @@ void Emulator::RenderCpuInstructionLog(
     ImGui::Checkbox("Show All Opcodes", &showAllOpcodes);
 
     // Instruction list
-    ImGui::BeginChild(
-        "InstructionList", ImVec2(0, 0),
-        ImGuiChildFlags_AlwaysAutoResize | ImGuiChildFlags_AutoResizeY);
+    ImGui::BeginChild("InstructionList", ImVec2(0, 0),
+                      ImGuiChildFlags_None);
     for (const auto& entry : instructionLog) {
       if (ShouldDisplay(entry, filterBuf, showAllOpcodes)) {
         if (ImGui::Selectable(

src/app/emu/emulator.h

@@ -43,6 +43,7 @@ class Emulator : public SharedROM {
   bool power_ = false;
   bool loading_ = false;
   bool running_ = false;
+  bool step_ = true;
 };
 
 }  // namespace emu

src/app/emu/snes.cc

@@ -112,7 +112,7 @@ void SNES::Init(ROM& rom) {
   cpu_.E = 0;
 
   // Initialize CPU
-  cpu_.Init(); 
+  cpu_.Init();
 
   // Read the ROM header
   auto header_offset = GetHeaderOffset(memory_);
@@ -211,6 +211,9 @@ void SNES::Init(ROM& rom) {
   // Misc
   memory_.WriteByte(0x2133, 0x00);  // SETINI
 
+  // Psuedo-Init
+  memory_.WriteWord(0x2140, 0xBBAA);
+
   running_ = true;
   scanline = 0;
 }
@@ -251,6 +254,22 @@ void SNES::Run() {
   }
 }
 
+void SNES::StepRun() {
+  // Update the CPU
+  cpu_.UpdateClock(0.0);
+  cpu_.Update(CPU::UpdateMode::Step);
+
+  // Update the PPU
+  ppu_.UpdateClock(0.0);
+  ppu_.Update();
+
+  // Update the APU
+  apu_.UpdateClock(0.0);
+  apu_.Update();
+
+  HandleInput();
+}
+
 // Enable NMI Interrupts
 void SNES::EnableVBlankInterrupts() {
   v_blank_flag_ = false;
@@ -363,14 +382,6 @@ void SNES::LoadState(const std::string& path) {
   // ...
 }
 
-void SNES::Debug() {
-  // ...
-}
-
-void SNES::Breakpoint(uint16_t address) {
-  // ...
-}
-
 }  // namespace emu
 }  // namespace app
 }  // namespace yaze

src/app/emu/snes.h

@@ -33,6 +33,9 @@ class SNES : public DMA {
   // Main emulation loop
   void Run();
 
+  // Step through a single instruction
+  void StepRun();
+
   // Enable NMI Interrupts
   void EnableVBlankInterrupts();
 
@@ -56,10 +59,6 @@ class SNES : public DMA {
   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_; }
 
   auto cpu() -> CPU& { return cpu_; }