GPU: Fix timer 1 IRQs sometimes triggering late

Should hopefully fix missing voices in Akuji the Heartless.
This commit is contained in:
Connor McLaughlin 2020-04-28 20:30:44 +10:00
parent a5ff904b33
commit 5a1b00825d
3 changed files with 38 additions and 7 deletions

View File

@ -568,20 +568,26 @@ TickCount GPU::GetPendingGPUTicks() const
void GPU::UpdateSliceTicks()
{
// figure out how many GPU ticks until the next vblank
// figure out how many GPU ticks until the next vblank or event
const TickCount lines_until_vblank =
(m_crtc_state.current_scanline >= m_crtc_state.vertical_display_end ?
(m_crtc_state.vertical_total - m_crtc_state.current_scanline + m_crtc_state.vertical_display_end) :
(m_crtc_state.vertical_display_end - m_crtc_state.current_scanline));
const TickCount ticks_until_vblank =
lines_until_vblank * m_crtc_state.horizontal_total - m_crtc_state.current_tick_in_scanline;
const TickCount lines_until_event = m_timers->IsExternalIRQEnabled(HBLANK_TIMER_INDEX) ?
std::min(m_timers->GetTicksUntilIRQ(HBLANK_TIMER_INDEX), lines_until_vblank) :
lines_until_vblank;
const TickCount ticks_until_event =
lines_until_event * m_crtc_state.horizontal_total - m_crtc_state.current_tick_in_scanline;
#if 0
const TickCount ticks_until_hblank =
(m_crtc_state.current_tick_in_scanline >= m_crtc_state.horizontal_display_end) ?
(m_crtc_state.horizontal_total - m_crtc_state.current_tick_in_scanline + m_crtc_state.horizontal_display_end) :
(m_crtc_state.horizontal_display_end - m_crtc_state.current_tick_in_scanline);
(m_crtc_state.horizontal_total - m_crtc_state.current_tick_in_scanline + m_crtc_state.horizontal_display_end) :
(m_crtc_state.horizontal_display_end - m_crtc_state.current_tick_in_scanline);
#endif
m_tick_event->Schedule(
GPUTicksToSystemTicks((m_command_ticks > 0) ? std::min(m_command_ticks, ticks_until_vblank) : ticks_until_vblank));
GPUTicksToSystemTicks((m_command_ticks > 0) ? std::min(m_command_ticks, ticks_until_event) : ticks_until_event));
}
bool GPU::IsRasterScanlinePending() const

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@ -89,6 +89,21 @@ void Timers::SetGate(u32 timer, bool state)
}
}
TickCount Timers::GetTicksUntilIRQ(u32 timer) const
{
const CounterState& cs = m_states[timer];
if (!cs.counting_enabled)
return std::numeric_limits<TickCount>::max();
TickCount ticks_until_irq = std::numeric_limits<TickCount>::max();
if (cs.mode.irq_at_target)
ticks_until_irq = static_cast<TickCount>(cs.target - cs.counter);
if (cs.mode.irq_on_overflow)
ticks_until_irq = std::min(ticks_until_irq, static_cast<TickCount>(0xFFFFu - cs.counter));
return ticks_until_irq;
}
void Timers::AddTicks(u32 timer, TickCount count)
{
CounterState& cs = m_states[timer];

View File

@ -27,6 +27,16 @@ public:
// dot clock/hblank/sysclk div 8
bool IsUsingExternalClock(u32 timer) const { return m_states[timer].external_counting_enabled; }
// queries for GPU
bool IsExternalIRQEnabled(u32 timer) const
{
const CounterState& cs = m_states[timer];
return (cs.external_counting_enabled && (cs.mode.bits & ((1u << 4) | (1u << 5))) != 0);
}
TickCount GetTicksUntilIRQ(u32 timer) const;
void AddTicks(u32 timer, TickCount ticks);
u32 ReadRegister(u32 offset);
@ -89,5 +99,5 @@ private:
std::unique_ptr<TimingEvent> m_sysclk_event;
std::array<CounterState, NUM_TIMERS> m_states{};
u32 m_sysclk_div_8_carry = 0; // partial ticks for timer 3 with sysclk/8
u32 m_sysclk_div_8_carry = 0; // partial ticks for timer 3 with sysclk/8
};