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Basic timer implementation

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This commit is contained in:
Connor McLaughlin
2019-09-20 23:40:19 +10:00
parent ad652c47ed
commit ad316162f3
14 changed files with 375 additions and 16 deletions
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27
src/pse/gpu.cpp
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@ -5,6 +5,7 @@
#include "interrupt_controller.h"
#include "stb_image_write.h"
#include "system.h"
#include "timers.h"
Log_SetChannel(GPU);
bool GPU::DUMP_CPU_TO_VRAM_COPIES = false;
@ -16,11 +17,12 @@ GPU::GPU() = default;
GPU::~GPU() = default;
bool GPU::Initialize(System* system, DMA* dma, InterruptController* interrupt_controller)
bool GPU::Initialize(System* system, DMA* dma, InterruptController* interrupt_controller, Timers* timers)
{
m_system = system;
m_dma = dma;
m_interrupt_controller = interrupt_controller;
m_timers = timers;
return true;
}
@ -254,12 +256,14 @@ void GPU::UpdateCRTCConfig()
void GPU::UpdateSliceTicks()
{
// the next event is at the end of the next scanline
// const TickCount ticks_until_next_event = m_crtc_state.ticks_per_scanline - m_crtc_state.current_tick_in_scanline;
#if 1
const TickCount ticks_until_next_event = m_crtc_state.ticks_per_scanline - m_crtc_state.current_tick_in_scanline;
#else
// or at vblank. this will depend on the timer config..
const TickCount ticks_until_next_event =
((m_crtc_state.total_scanlines_per_frame - m_crtc_state.current_scanline) * m_crtc_state.ticks_per_scanline) -
m_crtc_state.current_tick_in_scanline;
#endif
// convert to master clock, rounding up as we want to overshoot not undershoot
const TickCount system_ticks = (ticks_until_next_event * 7 + 10) / 11;
@ -279,13 +283,22 @@ void GPU::Execute(TickCount ticks)
{
m_crtc_state.current_tick_in_scanline -= m_crtc_state.ticks_per_scanline;
m_crtc_state.current_scanline++;
if (m_timers->IsUsingExternalClock(HBLANK_TIMER_INDEX))
m_timers->AddTicks(HBLANK_TIMER_INDEX, 1);
const bool old_vblank = m_crtc_state.in_vblank;
m_crtc_state.in_vblank = m_crtc_state.current_scanline >= m_crtc_state.visible_vertical_resolution;
if (m_crtc_state.in_vblank && !old_vblank)
const bool new_vblank = m_crtc_state.current_scanline >= m_crtc_state.visible_vertical_resolution;
if (new_vblank != old_vblank)
{
Log_DebugPrintf("Now in v-blank");
m_interrupt_controller->InterruptRequest(InterruptController::IRQ::VBLANK);
m_crtc_state.in_vblank = new_vblank;
if (!old_vblank)
{
Log_DebugPrintf("Now in v-blank");
m_interrupt_controller->InterruptRequest(InterruptController::IRQ::VBLANK);
}
m_timers->SetGate(HBLANK_TIMER_INDEX, new_vblank);
}
// past the end of vblank?