X64 Clock: Reduce accuracy to be less or equal to guest accuracy.

This commit is contained in:
Fernando Sahmkow 2020-03-21 12:23:13 -04:00
parent 7b18174eef
commit 534466754f
3 changed files with 10 additions and 1 deletions

View file

@ -62,7 +62,8 @@ u64 NativeClock::GetRTSC() {
}
accumulated_ticks += diff;
rtsc_serialize.unlock();
return accumulated_ticks;
/// The clock cannot be more precise than the guest timer, remove the lower bits
return accumulated_ticks & inaccuracy_mask;
}
void NativeClock::Pause(bool is_paused) {

View file

@ -31,6 +31,11 @@ public:
private:
u64 GetRTSC();
/// value used to reduce the native clocks accuracy as some apss rely on
/// undefined behavior where the level of accuracy in the clock shouldn't
/// be higher.
static constexpr u64 inaccuracy_mask = ~(0x100 - 1);
SpinLock rtsc_serialize{};
u64 last_measure{};
u64 accumulated_ticks{};

View file

@ -184,6 +184,9 @@ std::shared_ptr<Dynarmic::A64::Jit> ARM_Dynarmic_64::MakeJit(Common::PageTable&
config.enable_fast_dispatch = false;
}
// CNTPCT uses wall clock.
config.wall_clock_cntpct = true;
return std::make_shared<Dynarmic::A64::Jit>(config);
}