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GPU: Run draw clock at sysclk * 2

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This commit is contained in:
Connor McLaughlin 2020-06-13 01:28:49 +10:00
parent 0dfb9f7d90
commit dad63f2303
4 changed files with 150 additions and 98 deletions
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177
src/core/gpu.cpp
View file

@ -31,8 +31,10 @@ bool GPU::Initialize(HostDisplay* host_display, System* system, DMA* dma, Interr
m_force_ntsc_timings = m_system->GetSettings().gpu_force_ntsc_timings;
m_crtc_state.display_aspect_ratio =
Settings::GetDisplayAspectRatioValue(m_system->GetSettings().display_aspect_ratio);
m_tick_event =
m_system->CreateTimingEvent("GPU Tick", 1, 1, std::bind(&GPU::Execute, this, std::placeholders::_1), true);
m_crtc_tick_event = m_system->CreateTimingEvent("GPU CRTC Tick", 1, 1,
std::bind(&GPU::CRTCTickEvent, this, std::placeholders::_1), true);
m_command_tick_event = m_system->CreateTimingEvent(
"GPU Command Tick", 1, 1, std::bind(&GPU::CommandTickEvent, this, std::placeholders::_1), true);
m_fifo_size = system->GetSettings().gpu_fifo_size;
m_max_run_ahead = system->GetSettings().gpu_max_run_ahead;
m_console_is_pal = system->IsPALRegion();
@ -92,7 +94,7 @@ void GPU::SoftReset()
m_crtc_state.in_hblank = false;
m_crtc_state.in_vblank = false;
m_blitter_state = BlitterState::Idle;
m_command_ticks = 0;
m_pending_command_ticks = 0;
m_command_total_words = 0;
m_vram_transfer = {};
m_fifo.Clear();
@ -103,7 +105,8 @@ void GPU::SoftReset()
SetTextureWindow(0);
UpdateDMARequest();
UpdateCRTCConfig();
UpdateSliceTicks();
UpdateCRTCTickEvent();
UpdateCommandTickEvent();
}
bool GPU::DoState(StateWrapper& sw)
@ -172,7 +175,7 @@ bool GPU::DoState(StateWrapper& sw)
sw.Do(&m_crtc_state.active_line_lsb);
sw.Do(&m_blitter_state);
sw.Do(&m_command_ticks);
sw.Do(&m_pending_command_ticks);
sw.Do(&m_command_total_words);
sw.Do(&m_GPUREAD_latch);
@ -219,7 +222,8 @@ bool GPU::DoState(StateWrapper& sw)
UpdateCRTCConfig();
UpdateDisplay();
UpdateSliceTicks();
UpdateCRTCTickEvent();
UpdateCommandTickEvent();
}
else
{
@ -239,19 +243,16 @@ void GPU::UpdateDMARequest()
switch (m_blitter_state)
{
case BlitterState::Idle:
m_GPUSTAT.gpu_idle = (m_command_ticks <= 0);
m_GPUSTAT.ready_to_send_vram = false;
m_GPUSTAT.ready_to_recieve_dma = (m_fifo.GetSize() < m_fifo_size);
break;
case BlitterState::WritingVRAM:
m_GPUSTAT.gpu_idle = false;
m_GPUSTAT.ready_to_send_vram = false;
m_GPUSTAT.ready_to_recieve_dma = (m_fifo.GetSize() < m_fifo_size);
break;
case BlitterState::ReadingVRAM:
m_GPUSTAT.gpu_idle = false;
m_GPUSTAT.ready_to_send_vram = true;
m_GPUSTAT.ready_to_recieve_dma = false;
break;
@ -284,6 +285,24 @@ void GPU::UpdateDMARequest()
m_dma->SetRequest(DMA::Channel::GPU, dma_request);
}
void GPU::UpdateGPUIdle()
{
switch (m_blitter_state)
{
case BlitterState::Idle:
m_GPUSTAT.gpu_idle = (m_pending_command_ticks <= 0);
break;
case BlitterState::WritingVRAM:
m_GPUSTAT.gpu_idle = false;
break;
case BlitterState::ReadingVRAM:
m_GPUSTAT.gpu_idle = false;
break;
}
}
u32 GPU::ReadRegister(u32 offset)
{
switch (offset)
@ -295,8 +314,10 @@ u32 GPU::ReadRegister(u32 offset)
{
// code can be dependent on the odd/even bit, so update the GPU state when reading.
// we can mitigate this slightly by only updating when the raster is actually hitting a new line
if (IsRasterScanlineOrCommandPending())
Synchronize();
if (IsCRTCScanlinePending())
SynchronizeCRTC();
if (IsCommandCompletionPending())
m_command_tick_event->InvokeEarly();
return m_GPUSTAT.bits;
}
@ -314,6 +335,7 @@ void GPU::WriteRegister(u32 offset, u32 value)
case 0x00:
m_fifo.Push(value);
ExecuteCommands();
UpdateCommandTickEvent();
return;
case 0x04:
@ -348,9 +370,14 @@ void GPU::DMAWrite(const u32* words, u32 word_count)
m_fifo.PushRange(words, word_count);
m_fifo_pushed = true;
if (!m_syncing)
{
ExecuteCommands();
UpdateCommandTickEvent();
}
else
{
UpdateDMARequest();
}
}
break;
@ -372,7 +399,7 @@ void GPU::DMAWrite(const u32* words, u32 word_count)
* PAL - sysclk * 709379 / 451584
*/
TickCount GPU::GPUTicksToSystemTicks(TickCount gpu_ticks, TickCount fractional_ticks) const
TickCount GPU::CRTCTicksToSystemTicks(TickCount gpu_ticks, TickCount fractional_ticks) const
{
// convert to master clock, rounding up as we want to overshoot not undershoot
if (!m_console_is_pal)
@ -381,7 +408,7 @@ TickCount GPU::GPUTicksToSystemTicks(TickCount gpu_ticks, TickCount fractional_t
return static_cast<TickCount>((u64(gpu_ticks) * u64(451584) + fractional_ticks + u64(709378)) / u64(709379));
}
TickCount GPU::SystemTicksToGPUTicks(TickCount sysclk_ticks, TickCount* fractional_ticks) const
TickCount GPU::SystemTicksToCRTCTicks(TickCount sysclk_ticks, TickCount* fractional_ticks) const
{
if (!m_console_is_pal)
{
@ -401,30 +428,19 @@ TickCount GPU::SystemTicksToGPUTicks(TickCount sysclk_ticks, TickCount* fraction
void GPU::AddCommandTicks(TickCount ticks)
{
if (m_command_ticks != 0)
{
m_command_ticks += ticks;
return;
}
m_command_ticks = GetPendingGPUTicks() + ticks;
// reschedule GPU tick event if it would execute later than this command finishes
const TickCount sysclk_ticks = GPUTicksToSystemTicks(ticks, 0);
if (m_tick_event->GetTicksUntilNextExecution() > sysclk_ticks)
m_tick_event->Schedule(sysclk_ticks);
m_pending_command_ticks += ticks;
}
void GPU::Synchronize()
void GPU::SynchronizeCRTC()
{
m_tick_event->InvokeEarly();
m_crtc_tick_event->InvokeEarly();
}
float GPU::ComputeHorizontalFrequency() const
{
const CRTCState& cs = m_crtc_state;
TickCount fractional_ticks = 0;
return static_cast<float>(static_cast<double>(SystemTicksToGPUTicks(MASTER_CLOCK, &fractional_ticks)) /
return static_cast<float>(static_cast<double>(SystemTicksToCRTCTicks(MASTER_CLOCK, &fractional_ticks)) /
static_cast<double>(cs.horizontal_total));
}
@ -433,7 +449,7 @@ float GPU::ComputeVerticalFrequency() const
const CRTCState& cs = m_crtc_state;
const TickCount ticks_per_frame = cs.horizontal_total * cs.vertical_total;
TickCount fractional_ticks = 0;
return static_cast<float>(static_cast<double>(SystemTicksToGPUTicks(MASTER_CLOCK, &fractional_ticks)) /
return static_cast<float>(static_cast<double>(SystemTicksToCRTCTicks(MASTER_CLOCK, &fractional_ticks)) /
static_cast<double>(ticks_per_frame));
}
@ -486,7 +502,7 @@ void GPU::UpdateCRTCConfig()
m_system->SetThrottleFrequency(ComputeVerticalFrequency());
UpdateCRTCDisplayParameters();
UpdateSliceTicks();
UpdateCRTCTickEvent();
}
void GPU::UpdateCRTCDisplayParameters()
@ -628,14 +644,22 @@ void GPU::UpdateCRTCDisplayParameters()
}
}
TickCount GPU::GetPendingGPUTicks() const
TickCount GPU::GetPendingCRTCTicks() const
{
const TickCount pending_sysclk_ticks = m_tick_event->GetTicksSinceLastExecution();
const TickCount pending_sysclk_ticks = m_crtc_tick_event->GetTicksSinceLastExecution();
TickCount fractional_ticks = m_crtc_state.fractional_ticks;
return SystemTicksToGPUTicks(pending_sysclk_ticks, &fractional_ticks);
return SystemTicksToCRTCTicks(pending_sysclk_ticks, &fractional_ticks);
}
void GPU::UpdateSliceTicks()
TickCount GPU::GetPendingCommandTicks() const
{
if (!m_command_tick_event->IsActive())
return 0;
return SystemTicksToGPUTicks(m_command_tick_event->GetTicksSinceLastExecution());
}
void GPU::UpdateCRTCTickEvent()
{
// figure out how many GPU ticks until the next vblank or event
const TickCount lines_until_vblank =
@ -655,42 +679,25 @@ void GPU::UpdateSliceTicks()
(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_event) : ticks_until_event,
m_crtc_state.fractional_ticks));
m_crtc_tick_event->Schedule(CRTCTicksToSystemTicks(ticks_until_event, m_crtc_state.fractional_ticks));
}
bool GPU::IsRasterScanlinePending() const
bool GPU::IsCRTCScanlinePending() const
{
return (GetPendingGPUTicks() + m_crtc_state.current_tick_in_scanline) >= m_crtc_state.horizontal_total;
return (GetPendingCRTCTicks() + m_crtc_state.current_tick_in_scanline) >= m_crtc_state.horizontal_total;
}
bool GPU::IsRasterScanlineOrCommandPending() const
bool GPU::IsCommandCompletionPending() const
{
const TickCount pending_ticks = GetPendingGPUTicks();
return ((pending_ticks + m_crtc_state.current_tick_in_scanline) >= m_crtc_state.horizontal_total) ||
(m_command_ticks > 0 && pending_ticks > m_command_ticks);
return (m_pending_command_ticks > 0 && GetPendingCommandTicks() >= m_pending_command_ticks);
}
void GPU::Execute(TickCount ticks)
void GPU::CRTCTickEvent(TickCount ticks)
{
// convert cpu/master clock to GPU ticks, accounting for partial cycles because of the non-integer divider
{
const TickCount gpu_ticks = SystemTicksToGPUTicks(ticks, &m_crtc_state.fractional_ticks);
const TickCount gpu_ticks = SystemTicksToCRTCTicks(ticks, &m_crtc_state.fractional_ticks);
m_crtc_state.current_tick_in_scanline += gpu_ticks;
// handle blits
if (m_command_ticks > 0)
{
m_command_ticks -= gpu_ticks;
// we can be syncing if this came from a DMA write. recursively executing commands would be bad.
if (!m_syncing)
ExecuteCommands();
if (m_command_ticks < 0)
m_command_ticks = 0;
}
}
if (m_crtc_state.current_tick_in_scanline < m_crtc_state.horizontal_total)
@ -702,7 +709,7 @@ void GPU::Execute(TickCount ticks)
if (!old_hblank && new_hblank && m_timers->IsUsingExternalClock(HBLANK_TIMER_INDEX))
m_timers->AddTicks(HBLANK_TIMER_INDEX, 1);
UpdateSliceTicks();
UpdateCRTCTickEvent();
return;
}
@ -786,7 +793,36 @@ void GPU::Execute(TickCount ticks)
m_GPUSTAT.display_line_lsb = ConvertToBoolUnchecked((m_crtc_state.regs.Y + m_crtc_state.current_scanline) & u32(1));
}
UpdateSliceTicks();
UpdateCRTCTickEvent();
}
void GPU::CommandTickEvent(TickCount ticks)
{
m_pending_command_ticks -= SystemTicksToGPUTicks(ticks);
// we can be syncing if this came from a DMA write. recursively executing commands would be bad.
if (!m_syncing)
ExecuteCommands();
UpdateGPUIdle();
if (m_pending_command_ticks <= 0)
{
m_pending_command_ticks = 0;
m_command_tick_event->Deactivate();
}
else
{
m_command_tick_event->SetIntervalAndSchedule(GPUTicksToSystemTicks(m_pending_command_ticks));
}
}
void GPU::UpdateCommandTickEvent()
{
if (m_pending_command_ticks <= 0)
m_command_tick_event->Deactivate();
else if (!m_command_tick_event->IsActive())
m_command_tick_event->SetIntervalAndSchedule(GPUTicksToSystemTicks(m_pending_command_ticks));
}
bool GPU::ConvertScreenCoordinatesToBeamTicksAndLines(s32 window_x, s32 window_y, u32* out_tick, u32* out_line) const
@ -837,6 +873,7 @@ u32 GPU::ReadGPUREAD()
// end of transfer, catch up on any commands which were written (unlikely)
ExecuteCommands();
UpdateCommandTickEvent();
break;
}
}
@ -855,7 +892,7 @@ void GPU::WriteGP1(u32 value)
case 0x00: // Reset GPU
{
Log_DebugPrintf("GP1 reset GPU");
Synchronize();
SynchronizeCRTC();
SoftReset();
}
break;
@ -863,15 +900,17 @@ void GPU::WriteGP1(u32 value)
case 0x01: // Clear FIFO
{
Log_DebugPrintf("GP1 clear FIFO");
Synchronize();
SynchronizeCRTC();
m_blitter_state = BlitterState::Idle;
m_command_total_words = 0;
m_vram_transfer = {};
m_fifo.Clear();
m_blit_buffer.clear();
m_blit_remaining_words = 0;
m_command_ticks = 0;
m_pending_command_ticks = 0;
m_command_tick_event->Deactivate();
UpdateDMARequest();
UpdateGPUIdle();
}
break;
@ -886,7 +925,7 @@ void GPU::WriteGP1(u32 value)
{
const bool disable = ConvertToBoolUnchecked(value & 0x01);
Log_DebugPrintf("Display %s", disable ? "disabled" : "enabled");
Synchronize();
SynchronizeCRTC();
m_GPUSTAT.display_disable = disable;
}
break;
@ -918,7 +957,7 @@ void GPU::WriteGP1(u32 value)
if (m_crtc_state.regs.horizontal_display_range != new_value)
{
Synchronize();
SynchronizeCRTC();
m_crtc_state.regs.horizontal_display_range = new_value;
UpdateCRTCConfig();
}
@ -932,7 +971,7 @@ void GPU::WriteGP1(u32 value)
if (m_crtc_state.regs.vertical_display_range != new_value)
{
Synchronize();
SynchronizeCRTC();
m_crtc_state.regs.vertical_display_range = new_value;
UpdateCRTCConfig();
}
@ -969,7 +1008,7 @@ void GPU::WriteGP1(u32 value)
{
// Have to be careful when setting this because Synchronize() can modify GPUSTAT.
static constexpr u32 SET_MASK = UINT32_C(0b00000000011111110100000000000000);
Synchronize();
SynchronizeCRTC();
m_GPUSTAT.bits = (m_GPUSTAT.bits & ~SET_MASK) | (new_GPUSTAT.bits & SET_MASK);
UpdateCRTCConfig();
}
@ -1077,8 +1116,8 @@ void GPU::FillVRAM(u32 x, u32 y, u32 width, u32 height, u32 color)
else if (IsInterlacedRenderingEnabled())
{
// Hardware tests show that fills seem to break on the first two lines when the offset matches the displayed field.
if (IsRasterScanlinePending())
Synchronize();
if (IsCRTCScanlinePending())
SynchronizeCRTC();
const u32 active_field = GetActiveLineLSB();
for (u32 yoffs = 0; yoffs < height; yoffs++)

32
src/core/gpu.h
View file

@ -143,16 +143,17 @@ public:
void DMAWrite(const u32* words, u32 word_count);
/// Returns the number of pending GPU ticks.
TickCount GetPendingGPUTicks() const;
TickCount GetPendingCRTCTicks() const;
TickCount GetPendingCommandTicks() const;
/// Returns true if enough ticks have passed for the raster to be on the next line.
bool IsRasterScanlinePending() const;
bool IsCRTCScanlinePending() const;
/// Returns true if a raster scanline or command execution is pending.
bool IsRasterScanlineOrCommandPending() const;
bool IsCommandCompletionPending() const;
// Synchronizes the CRTC, updating the hblank timer.
void Synchronize();
void SynchronizeCRTC();
// Recompile shaders/recreate framebuffers when needed.
virtual void UpdateSettings();
@ -173,8 +174,15 @@ public:
void UpdateHardwareType();
protected:
TickCount GPUTicksToSystemTicks(TickCount gpu_ticks, TickCount fractional_ticks) const;
TickCount SystemTicksToGPUTicks(TickCount sysclk_ticks, TickCount* fractional_ticks) const;
TickCount CRTCTicksToSystemTicks(TickCount crtc_ticks, TickCount fractional_ticks) const;
TickCount SystemTicksToCRTCTicks(TickCount sysclk_ticks, TickCount* fractional_ticks) const;
// The GPU internally appears to run at 2x the system clock.
ALWAYS_INLINE static constexpr TickCount GPUTicksToSystemTicks(TickCount gpu_ticks)
{
return std::max<TickCount>(gpu_ticks >> 1, 1);
}
ALWAYS_INLINE static constexpr TickCount SystemTicksToGPUTicks(TickCount sysclk_ticks) { return sysclk_ticks << 1; }
// Helper/format conversion functions.
static constexpr u8 Convert5To8(u8 x5) { return (x5 << 3) | (x5 & 7); }
@ -332,13 +340,16 @@ protected:
void UpdateCRTCDisplayParameters();
// Update ticks for this execution slice
void UpdateSliceTicks();
void UpdateCRTCTickEvent();
void UpdateCommandTickEvent();
// Updates dynamic bits in GPUSTAT (ready to send VRAM/ready to receive DMA)
void UpdateDMARequest();
void UpdateGPUIdle();
// Ticks for hblank/vblank.
void Execute(TickCount ticks);
void CRTCTickEvent(TickCount ticks);
void CommandTickEvent(TickCount ticks);
/// Returns false if the DAC is loading any data from VRAM.
ALWAYS_INLINE bool IsDisplayDisabled() const
@ -419,7 +430,8 @@ protected:
InterruptController* m_interrupt_controller = nullptr;
Timers* m_timers = nullptr;
std::unique_ptr<TimingEvent> m_tick_event;
std::unique_ptr<TimingEvent> m_crtc_tick_event;
std::unique_ptr<TimingEvent> m_command_tick_event;
// Pointer to VRAM, used for reads/writes. In the hardware backends, this is the shadow buffer.
u16* m_vram_ptr = nullptr;
@ -649,8 +661,8 @@ protected:
} m_crtc_state = {};
BlitterState m_blitter_state = BlitterState::Idle;
TickCount m_command_ticks = 0;
u32 m_command_total_words = 0;
TickCount m_pending_command_ticks = 0;
/// GPUREAD value for non-VRAM-reads.
u32 m_GPUREAD_latch = 0;

27
src/core/gpu_commands.cpp
View file

@ -27,7 +27,7 @@ void GPU::ExecuteCommands()
for (;;)
{
if (m_command_ticks <= m_max_run_ahead && !m_fifo.IsEmpty())
if (m_pending_command_ticks <= m_max_run_ahead && !m_fifo.IsEmpty())
{
switch (m_blitter_state)
{
@ -108,6 +108,7 @@ void GPU::ExecuteCommands()
break;
}
UpdateGPUIdle();
m_syncing = false;
}
@ -325,8 +326,8 @@ bool GPU::HandleRenderPolygonCommand()
const u32 total_words = words_per_vertex * num_vertices + BoolToUInt32(!rc.shading_enable);
CHECK_COMMAND_SIZE(total_words);
if (IsInterlacedRenderingEnabled() && IsRasterScanlinePending())
Synchronize();
if (IsInterlacedRenderingEnabled() && IsCRTCScanlinePending())
SynchronizeCRTC();
// setup time
static constexpr u16 s_setup_time[2][2][2] = {{{46, 226}, {334, 496}}, {{82, 262}, {370, 532}}};
@ -367,8 +368,8 @@ bool GPU::HandleRenderRectangleCommand()
CHECK_COMMAND_SIZE(total_words);
if (IsInterlacedRenderingEnabled() && IsRasterScanlinePending())
Synchronize();
if (IsInterlacedRenderingEnabled() && IsCRTCScanlinePending())
SynchronizeCRTC();
if (rc.texture_enable)
SetTexturePalette(Truncate16(m_fifo.Peek(2) >> 16));
@ -397,8 +398,8 @@ bool GPU::HandleRenderLineCommand()
const u32 total_words = rc.shading_enable ? 4 : 3;
CHECK_COMMAND_SIZE(total_words);
if (IsInterlacedRenderingEnabled() && IsRasterScanlinePending())
Synchronize();
if (IsInterlacedRenderingEnabled() && IsCRTCScanlinePending())
SynchronizeCRTC();
Log_TracePrintf("Render %s %s line (%u total words)", rc.transparency_enable ? "semi-transparent" : "opaque",
rc.shading_enable ? "shaded" : "monochrome", total_words);
@ -420,8 +421,8 @@ bool GPU::HandleRenderPolyLineCommand()
const u32 min_words = rc.shading_enable ? 3 : 4;
CHECK_COMMAND_SIZE(min_words);
if (IsInterlacedRenderingEnabled() && IsRasterScanlinePending())
Synchronize();
if (IsInterlacedRenderingEnabled() && IsCRTCScanlinePending())
SynchronizeCRTC();
const TickCount setup_ticks = 16;
AddCommandTicks(setup_ticks);
@ -446,8 +447,8 @@ bool GPU::HandleFillRectangleCommand()
{
CHECK_COMMAND_SIZE(3);
if (IsInterlacedRenderingEnabled() && IsRasterScanlinePending())
Synchronize();
if (IsInterlacedRenderingEnabled() && IsCRTCScanlinePending())
SynchronizeCRTC();
FlushRender();
@ -502,8 +503,8 @@ void GPU::FinishVRAMWrite()
m_blit_buffer.data(), true);
}
if (IsInterlacedRenderingEnabled() && IsRasterScanlinePending())
Synchronize();
if (IsInterlacedRenderingEnabled() && IsCRTCScanlinePending())
SynchronizeCRTC();
FlushRender();

12
src/core/timers.cpp
View file

@ -182,8 +182,8 @@ u32 Timers::ReadRegister(u32 offset)
if (timer_index < 2 && cs.external_counting_enabled)
{
// timers 0/1 depend on the GPU
if (timer_index == 0 || m_gpu->IsRasterScanlinePending())
m_gpu->Synchronize();
if (timer_index == 0 || m_gpu->IsCRTCScanlinePending())
m_gpu->SynchronizeCRTC();
}
m_sysclk_event->InvokeEarly();
@ -196,8 +196,8 @@ u32 Timers::ReadRegister(u32 offset)
if (timer_index < 2 && cs.external_counting_enabled)
{
// timers 0/1 depend on the GPU
if (timer_index == 0 || m_gpu->IsRasterScanlinePending())
m_gpu->Synchronize();
if (timer_index == 0 || m_gpu->IsCRTCScanlinePending())
m_gpu->SynchronizeCRTC();
}
m_sysclk_event->InvokeEarly();
@ -227,8 +227,8 @@ void Timers::WriteRegister(u32 offset, u32 value)
if (timer_index < 2 && cs.external_counting_enabled)
{
// timers 0/1 depend on the GPU
if (timer_index == 0 || m_gpu->IsRasterScanlinePending())
m_gpu->Synchronize();
if (timer_index == 0 || m_gpu->IsCRTCScanlinePending())
m_gpu->SynchronizeCRTC();
}
m_sysclk_event->InvokeEarly();