timing: refactored timing constants to timing.h

src/device/gpu/gpu.cpp

@@ -7,6 +7,7 @@
 #include "utils/file.h"
 #include "utils/logic.h"
 #include "utils/macros.h"
+#include "utils/timing.h"
 
 // For vram dump
 #include <stb_image_write.h>
@@ -793,7 +794,7 @@ bool GPU::emulateGpuCycles(int cycles) {
     gpuDot %= 3413;
     gpuLine += newLines;
 
-    if (gpuLine < LINE_VBLANK_START_NTSC - 1) {
+    if (gpuLine < timing::LINE_VBLANK_START_NTSC - 1) {
         if (gp1_08.verticalResolution == GP1_08::VerticalResolution::r480 && gp1_08.interlace) {
             odd = (frames % 2) != 0;
         } else {
@@ -803,7 +804,7 @@ bool GPU::emulateGpuCycles(int cycles) {
         odd = false;
     }
 
-    if (gpuLine == LINES_TOTAL_NTSC - 1) {
+    if (gpuLine == timing::LINES_TOTAL_NTSC - 1) {
         gpuLine = 0;
         frames++;
         return true;

src/device/gpu/gpu.h

@@ -17,9 +17,6 @@ namespace gpu {
 const int VRAM_WIDTH = 1024;
 const int VRAM_HEIGHT = 512;
 
-const int LINE_VBLANK_START_NTSC = 243;
-const int LINES_TOTAL_NTSC = 263;
-
 class GPU {
     friend struct ::System;
     friend class ::Render;

src/platform/windows/main.cpp

@@ -41,7 +41,7 @@ double limitFramerate(bool framelimiter, bool ntsc) {
     double currentTime = SDL_GetPerformanceCounter() / counterFrequency;
     double deltaTime = currentTime - startTime;
 
-    double frameTime = ntsc ? (1.0 / 60.0) : (1.0 / 50.0);
+    double frameTime = ntsc ? (1.0 / timing::NTSC_FRAMERATE) : (1.0 / 50.0);
 
     if (framelimiter && deltaTime < frameTime) {
         // If deltaTime was shorter than frameTime - spin

src/system.cpp

@@ -332,7 +332,7 @@ void System::singleStep() {
     state = State::pause;
 
     dma->step();
-    cdrom->step();
+    cdrom->step(3);
     timer[0]->step(3);
     timer[1]->step(3);
     timer[2]->step(3);
@@ -377,7 +377,7 @@ void System::emulateFrame() {
         }
 
         dma->step();
-        cdrom->step();
+        cdrom->step(systemCycles / 1.5f);
         timer[0]->step(systemCycles);
         timer[1]->step(systemCycles);
         timer[2]->step(systemCycles);
@@ -409,7 +409,7 @@ void System::emulateFrame() {
         }
 
         // TODO: Move this code to Timer class
-        if (gpu->gpuLine > gpu::LINE_VBLANK_START_NTSC) {
+        if (gpu->gpuLine > timing::LINE_VBLANK_START_NTSC) {
             auto& t = *timer[1];
             if (t.mode.syncEnabled) {
                 using modes = device::timer::CounterMode::SyncMode1;

src/system.h

@@ -15,6 +15,7 @@
 #include "device/spu/spu.h"
 #include "device/timer.h"
 #include "utils/macros.h"
+#include "utils/timing.h"
 
 #include <memory>
 #include <vector>

src/utils/timing.h

@@ -0,0 +1,16 @@
+#pragma once
+#include <cstdint>
+
+namespace timing {
+constexpr uint64_t US_IN_SECOND = 1'000'000;
+constexpr uint64_t CPU_CLOCK = 33'868'800;  // 44100 * 768
+constexpr uint64_t GPU_CLOCK = 53'222'400;
+
+// NTSC
+const float DOTS_TOTAL = 3413.6f;
+const int LINE_VBLANK_START_NTSC = 243;
+const int LINES_TOTAL_NTSC = 263;
+const float NTSC_FRAMERATE = (float)GPU_CLOCK / (DOTS_TOTAL * LINES_TOTAL_NTSC);
+
+constexpr uint64_t usToCpuCycles(uint64_t us) { return us * CPU_CLOCK / US_IN_SECOND; }
+}  // namespace timing