Function VSyncStart

pcsx2/Counters.cpp:487–543

}

static __fi void VSyncStart(u64 sCycle)
{
	// End-of-frame tasks.
	DoFMVSwitch();
	VMManager::Internal::VSyncOnCPUThread();

	// Don't bother throttling if we're going to pause.
	if (!VMManager::Internal::IsExecutionInterrupted())
		VMManager::Internal::Throttle();

	gsPostVsyncStart(); // MUST be after framelimit; doing so before causes funk with frame times!

	// Poll input after MTGS frame push, just in case it has to stall to catch up.
	VMManager::Internal::PollInputOnCPUThread();

	EECNT_LOG("    ================  EE COUNTER VSYNC START (frame: %d)  ================", g_FrameCount);

	// Memcard auto ejection - Uses a tick system timed off of real time, decrementing one tick per frame.
	AutoEject::CountDownTicks();
	// Memcard IO detection - Uses a tick system to determine when memcards are no longer being written.
	MemcardBusy::Decrement();

	if (!GSSMODE1reg.SINT)
	{
		hwIntcIrq(INTC_VBLANK_S);
		rcntStartGate(true, sCycle); // Counters Start Gate code
		psxVBlankStart();
	}

	// INTC - VB Blank Start Hack --
	// Hack fix!  This corrects a freezeup in Granda 2 where it decides to spin
	// on the INTC_STAT register after the exception handler has already cleared
	// it.  But be warned!  Set the value to larger than 4 and it breaks Dark
	// Cloud and other games. -_-

	// How it works: Normally the INTC raises exceptions immediately at the end of the
	// current branch test.  But in the case of Grandia 2, the game's code is spinning
	// on the INTC status, and the exception handler (for some reason?) clears the INTC
	// before returning *and* returns to a location other than EPC.  So the game never
	// gets to the point where it sees the INTC Irq set true.

	// (I haven't investigated why Dark Cloud freezes on larger values)
	// (all testing done using the recompiler -- dunno how the ints respond yet)

	//cpuRegs.eCycle[30] = 2;

	// Update 08/2021: The only game I know to require this kind of thing as of 1.7.0 is Penny Racers/Gadget Racers (which has a patch to avoid the problem and others)
	// These games have a tight loop checking INTC_STAT waiting for the VBLANK Start, however the game also has a VBLANK Hander which clears it.
	// Therefore, there needs to be some delay in order for it to see the interrupt flag before the interrupt is acknowledged, likely helped on real hardware by the pipelines.
	// Without the patch and fixing this, the games have other issues, so I'm not going to rush to fix it.
	// Refraction

	// Bail out before the next frame starts if we're paused, or the CPU has changed.
	// Need to re-check this, because we might've paused during the sleep time.
	if (VMManager::Internal::IsExecutionInterrupted())
		Cpu->ExitExecution();
}