Idle skipping... maybe?

src/backend/Core.cpp

@@ -110,6 +110,15 @@ void Core::Run(const float volumeL, const float volumeR) {
             }
 
             while (cycles < mem->mmio.vi.cyclesPerHalfline) {
+                if (IsAnythingSkippable()) {
+                    const u32 taken = Scheduler::GetInstance().events.top().time - Scheduler::GetInstance().ticks;
+                    cycles += taken;
+                    frameCycles += taken;
+                    Scheduler::GetInstance().Tick(taken);
+                    isReadingAnyIO = false;
+                    continue;
+                }
+
                 const u32 taken = StepCPU();
                 cycles += taken;
 
@@ -141,4 +150,9 @@ void Core::Run(const float volumeL, const float volumeR) {
     if (broken)
         pause = true;
 }
+
+bool Core::IsAnythingSkippable() {
+    MMIO &mmio = mem->mmio;
+    return (mmio.si.status.dmaBusy || mmio.pi.dmaBusy || mmio.pi.ioBusy) && isReadingAnyIO;
+}
 } // namespace n64