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CDROM: Further adjust IRQ delay
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Fixes audio dropouts in Crime Crackers, Ogre Battle seems fine now as
well.
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stenzek committed Jul 17, 2024
1 parent 9392c19 commit f1ca914
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Showing 3 changed files with 18 additions and 8 deletions.
3 changes: 3 additions & 0 deletions data/resources/gamedb.yaml
Original file line number Diff line number Diff line change
Expand Up @@ -30711,6 +30711,9 @@ SCPS-10003:
name: "Crime Crackers (Japan)"
controllers:
- DigitalController
settings:
dmaMaxSliceTicks: 100 # Stops DMA from blazing past the deferred CDROM async interrupt.
displayActiveEndOffset: -1 # Fixes garbage on edge of screen in cutscenes.
codes:
- HASH-111C340E270B10A8
metadata:
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18 changes: 11 additions & 7 deletions src/core/cdrom.cpp
Original file line number Diff line number Diff line change
Expand Up @@ -60,8 +60,8 @@ enum : u32
MAX_FAST_FORWARD_RATE = 12,
FAST_FORWARD_RATE_STEP = 4,

MINIMUM_INTERRUPT_DELAY = 6000,
INTERRUPT_DELAY_CYCLES = 2000,
MINIMUM_INTERRUPT_DELAY = 1000,
INTERRUPT_DELAY_CYCLES = 500,
};

static constexpr u8 INTERRUPT_REGISTER_MASK = 0x1F;
Expand Down Expand Up @@ -1033,9 +1033,16 @@ void CDROM::WriteRegister(u32 offset, u8 value)
case 5:
{
DEBUG_LOG("Interrupt flag register <- 0x{:02X}", value);

const u8 prev_interrupt_flag_register = s_interrupt_flag_register;
s_interrupt_flag_register &= ~(value & INTERRUPT_REGISTER_MASK);
if (s_interrupt_flag_register == 0)
{
// Start the countdown from when the interrupt was cleared, not it being triggered.
// Otherwise Ogre Battle, Crime Crackers, Lego Racers, etc have issues.
if (prev_interrupt_flag_register != 0)
s_last_interrupt_time = System::GetGlobalTickCounter();

InterruptController::SetLineState(InterruptController::IRQ::CDROM, false);
if (HasPendingAsyncInterrupt() && !HasPendingCommand())
QueueDeliverAsyncInterrupt();
Expand Down Expand Up @@ -1159,7 +1166,6 @@ bool CDROM::HasPendingAsyncInterrupt()
void CDROM::SetInterrupt(Interrupt interrupt)
{
s_interrupt_flag_register = static_cast<u8>(interrupt);
s_last_interrupt_time = System::GetGlobalTickCounter();
UpdateInterruptRequest();
}

Expand Down Expand Up @@ -1205,14 +1211,12 @@ void CDROM::QueueDeliverAsyncInterrupt()
// interrupt, then read the FIFO. If an INT1 comes in during that time, it'll read the INT1 response
// instead of the INT3 response, and the game gets confused. So, we just delay INT1s a bit, if there
// has been any recent INT3s - give it enough time to read the response out. The real console does
// something similar anyway, the INT1 task won't run immediately after the INT3 is cleared. We use
// the response FIFO being empty as a second heuristic, to avoid very late INT1s that cause early
// buffer loads and sector retries in other games, like Lego Racers PAL.
// something similar anyway, the INT1 task won't run immediately after the INT3 is cleared.
DebugAssert(HasPendingAsyncInterrupt());

// underflows here are okay
const u32 diff = System::GetGlobalTickCounter() - s_last_interrupt_time;
if (diff >= MINIMUM_INTERRUPT_DELAY || s_response_fifo.IsEmpty())
if (diff >= MINIMUM_INTERRUPT_DELAY)
{
DeliverAsyncInterrupt(nullptr, 0, 0);
}
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5 changes: 4 additions & 1 deletion src/core/system.cpp
Original file line number Diff line number Diff line change
Expand Up @@ -555,7 +555,10 @@ void System::UpdateOverclock()

u32 System::GetGlobalTickCounter()
{
return TimingEvents::GetGlobalTickCounter() + CPU::GetPendingTicks();
// When running events, the counter actually goes backwards, because the pending ticks are added in chunks.
// So, we need to return the counter with all pending ticks added in such cases.
return TimingEvents::IsRunningEvents() ? TimingEvents::GetEventRunTickCounter() :
(TimingEvents::GetGlobalTickCounter() + CPU::GetPendingTicks());
}

u32 System::GetFrameNumber()
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