Mesen-S/Core/GbPpu.cpp
2022-07-15 05:11:42 +02:00

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#include "stdafx.h"
#include "GbPpu.h"
#include "GbTypes.h"
#include "EventType.h"
#include "Console.h"
#include "EmuSettings.h"
#include "Gameboy.h"
#include "VideoDecoder.h"
#include "RewindManager.h"
#include "GbMemoryManager.h"
#include "GbDmaController.h"
#include "NotificationManager.h"
#include "MessageManager.h"
#include "SuperGameboy.h"
#include "../Utilities/HexUtilities.h"
#include "../Utilities/Serializer.h"
void GbPpu::Init(Console* console, Gameboy* gameboy, GbMemoryManager* memoryManager, GbDmaController* dmaController, uint8_t* vram, uint8_t* oam)
{
_console = console;
_gameboy = gameboy;
_memoryManager = memoryManager;
_dmaController = dmaController;
_vram = vram;
_oam = oam;
_outputBuffers[0] = new uint16_t[256 * 240];
_outputBuffers[1] = new uint16_t[256 * 240];
memset(_outputBuffers[0], 0, 256 * 240 * sizeof(uint16_t));
memset(_outputBuffers[1], 0, 256 * 240 * sizeof(uint16_t));
_currentBuffer = _outputBuffers[0];
_eventViewerBuffers[0] = new uint16_t[456 * 154];
_eventViewerBuffers[1] = new uint16_t[456 * 154];
memset(_eventViewerBuffers[0], 0, 456 * 154 * sizeof(uint16_t));
memset(_eventViewerBuffers[1], 0, 456 * 154 * sizeof(uint16_t));
_currentEventViewerBuffer = _eventViewerBuffers[0];
_state = {};
_state.Cycle = -1;
_state.Mode = PpuMode::HBlank;
_state.CgbEnabled = _gameboy->IsCgb();
_lastFrameTime = 0;
UpdatePalette();
Write(0xFF48, 0xFF);
Write(0xFF49, 0xFF);
}
GbPpu::~GbPpu()
{
}
GbPpuState GbPpu::GetState()
{
return _state;
}
uint16_t* GbPpu::GetOutputBuffer()
{
return _currentBuffer;
}
uint16_t* GbPpu::GetEventViewerBuffer()
{
return _currentEventViewerBuffer;
}
uint16_t* GbPpu::GetPreviousEventViewerBuffer()
{
return _currentEventViewerBuffer == _eventViewerBuffers[0] ? _eventViewerBuffers[1] : _eventViewerBuffers[0];
}
void GbPpu::Exec()
{
if(!_state.LcdEnabled) {
//LCD is disabled, prevent IRQs, etc.
//Not quite correct in terms of frame pacing
if(_gameboy->GetApuCycleCount() - _lastFrameTime > 70224) {
//More than a full frame's worth of time has passed since the last frame, send another blank frame
_lastFrameTime = _gameboy->GetApuCycleCount();
SendFrame();
}
return;
}
uint8_t cyclesToRun = _memoryManager->IsHighSpeed() ? 1 : 2;
for(int i = 0; i < cyclesToRun; i++) {
_state.Cycle++;
if(_state.IdleCycles > 0) {
_state.IdleCycles--;
ProcessPpuCycle();
continue;
}
ExecCycle();
}
}
void GbPpu::ExecCycle()
{
PpuMode oldMode = _state.IrqMode;
if(_state.Scanline < 144) {
if(_state.Scanline == 0 && _isFirstFrame) {
ProcessFirstScanlineAfterPowerOn();
} else {
ProcessVisibleScanline();
}
} else {
ProcessVblankScanline();
}
if(_state.Mode == PpuMode::Drawing) {
RunDrawCycle();
if(_drawnPixels == 160) {
//Mode turns to hblank on the same cycle as the last pixel is output (IRQ is on next cycle)
_state.Mode = PpuMode::HBlank;
if(_state.Scanline < 143) {
//"This mode will transfer one block (16 bytes) during each H-Blank. No data is transferred during VBlank (LY = 143 <20> 153)"
_dmaController->ProcessHdma();
}
}
} else if(_state.Mode == PpuMode::OamEvaluation) {
RunSpriteEvaluation();
}
bool coincidenceFlag = (_state.LyCompare == _state.LyForCompare);
if(_state.IrqMode != oldMode || _state.LyCoincidenceFlag != coincidenceFlag) {
_state.LyCoincidenceFlag = coincidenceFlag;
UpdateStatIrq();
}
ProcessPpuCycle();
}
void GbPpu::ProcessVblankScanline()
{
switch(_state.Cycle) {
case 2:
if(_state.Scanline == 144) {
_state.IrqMode = PpuMode::OamEvaluation;
}
break;
case 4:
if(_state.Scanline < 153) {
_state.LyForCompare = _state.Scanline;
if(_state.Scanline == 144) {
_state.Mode = PpuMode::VBlank;
_state.IrqMode = PpuMode::VBlank;
_windowCounter = -1;
_memoryManager->RequestIrq(GbIrqSource::VerticalBlank);
SendFrame();
}
}
break;
case 6:
if(_state.Scanline == 153) {
_state.Ly = 0;
_state.LyForCompare = _state.Scanline;
}
break;
case 8:
if(_state.Scanline == 153) {
_state.LyForCompare = -1;
}
break;
case 12:
if(_state.Scanline == 153) {
_state.LyForCompare = 0;
}
_state.IdleCycles = 456 - 12 - 1;
break;
case 456:
_state.Cycle = 0;
_state.Scanline++;
if(_state.Scanline == 154) {
_state.Scanline = 0;
_state.Ly = 0;
_state.LyForCompare = 0;
} else {
_state.Ly = _state.Scanline;
_state.LyForCompare = -1;
}
break;
}
}
void GbPpu::ProcessFirstScanlineAfterPowerOn()
{
if(_drawnPixels == 160) {
//IRQ flag for Hblank is 1 cycle late compared to the mode register
_state.IrqMode = PpuMode::HBlank;
_drawnPixels = 0;
_state.IdleCycles = 448 - _state.Cycle - 1;
}
switch(_state.Cycle) {
case 1:
_state.IrqMode = PpuMode::NoIrq;
break;
case 79:
_latchWindowX = _state.WindowX;
_latchWindowY = _state.WindowY;
_latchWindowEnabled = _state.WindowEnabled;
_state.Mode = PpuMode::Drawing;
_state.IrqMode = PpuMode::Drawing;
ResetRenderer();
_rendererIdle = true;
break;
case 84:
_rendererIdle = false;
break;
case 448:
_state.Cycle = 0;
_state.Scanline++;
_drawnPixels = 0;
_state.Mode = PpuMode::HBlank;
_state.IrqMode = PpuMode::HBlank;
break;
}
}
void GbPpu::ProcessVisibleScanline()
{
if(_drawnPixels == 160) {
//IRQ flag for Hblank is 1 cycle late compared to the mode register
_state.IrqMode = PpuMode::HBlank;
_drawnPixels = 0;
_state.IdleCycles = 456 - _state.Cycle - 1;
}
switch(_state.Cycle) {
case 3:
_state.Ly = _state.Scanline;
if(_state.Scanline > 0) {
//On scanlines 1-143, the OAM IRQ fires 1 cycle early
_state.IrqMode = PpuMode::OamEvaluation;
_state.LyForCompare = -1;
} else {
//On scanline 0, hblank gets set for 1 cycle here
_state.Mode = PpuMode::HBlank;
}
break;
case 4:
_spriteCount = 0;
_state.LyForCompare = _state.Scanline;
_state.Mode = PpuMode::OamEvaluation;
_state.IrqMode = PpuMode::OamEvaluation;
break;
case 5:
//Turning on OAM IRQs in the middle of evaluation has no effect?
//Or is this a patch to get the proper behavior for the STAT write bug?
_state.IrqMode = PpuMode::NoIrq;
break;
case 84:
_latchWindowX = _state.WindowX;
_latchWindowY = _state.WindowY;
_latchWindowEnabled = _state.WindowEnabled;
_state.Mode = PpuMode::Drawing;
_state.IrqMode = PpuMode::Drawing;
_rendererIdle = true;
ResetRenderer();
break;
case 89:
_rendererIdle = false;
break;
case 456:
_state.Cycle = 0;
_state.Scanline++;
if(_state.Scanline == 144) {
_state.Ly = 144;
_state.LyForCompare = -1;
}
break;
}
}
void GbPpu::ProcessPpuCycle()
{
}
void GbPpu::RunDrawCycle()
{
if(_rendererIdle) {
//Idle cycles
_evtColor = EvtColor::RenderingIdle;
return;
}
bool fetchWindow = _latchWindowEnabled && _drawnPixels >= _latchWindowX - 7 && _state.Scanline >= _latchWindowY;
if(_fetchWindow != fetchWindow) {
//Switched between window & background, reset fetcher & pixel FIFO
_fetchWindow = fetchWindow;
_fetchColumn = 0;
_windowCounter++;
_bgFetcher.Step = 0;
_bgFifo.Reset();
//Idle cycle when switching to window
_evtColor = EvtColor::RenderingIdle;
return;
}
FindNextSprite();
if(_fetchSprite >= 0 && _bgFetcher.Step >= 5 && _bgFifo.Size > 0) {
_evtColor = EvtColor::RenderingOamLoad;
ClockSpriteFetcher();
FindNextSprite();
return;
}
if(_fetchSprite == -1 && _bgFifo.Size > 0) {
if(_drawnPixels >= 0) {
uint16_t outOffset = _state.Scanline * 256 + _drawnPixels;
GbFifoEntry entry = _bgFifo.Content[_bgFifo.Position];
GbFifoEntry sprite = _oamFifo.Content[_oamFifo.Position];
if(sprite.Color != 0 && (entry.Color == 0 || (!(sprite.Attributes & 0x80) && !(entry.Attributes & 0x80)) || (_state.CgbEnabled && !_state.BgEnabled))) {
//Use sprite pixel if:
// -BG color is 0, OR
// -Sprite is background priority AND BG does not have its priority bit set, OR
// -On CGB, the "bg enabled" flag is cleared, causing all sprites to appear above BG tiles
if(_state.CgbEnabled) {
_currentBuffer[outOffset] = _state.CgbObjPalettes[sprite.Color | ((sprite.Attributes & 0x07) << 2)];
} else {
uint8_t colorIndex = (((sprite.Attributes & 0x10) ? _state.ObjPalette1 : _state.ObjPalette0) >> (sprite.Color * 2)) & 0x03;
if(_gameboy->IsSgb()) {
_gameboy->GetSgb()->WriteLcdColor(_state.Scanline, (uint8_t)_drawnPixels, colorIndex);
}
_currentBuffer[outOffset] = _state.CgbObjPalettes[((sprite.Attributes & 0x10) ? 4 : 0) | colorIndex];
}
} else {
if(_state.CgbEnabled) {
_currentBuffer[outOffset] = _state.CgbBgPalettes[entry.Color | ((entry.Attributes & 0x07) << 2)];
} else {
uint8_t colorIndex = (_state.BgPalette >> (entry.Color * 2)) & 0x03;
if(_gameboy->IsSgb()) {
_gameboy->GetSgb()->WriteLcdColor(_state.Scanline, (uint8_t)_drawnPixels, colorIndex);
}
_currentBuffer[outOffset] = _state.CgbBgPalettes[colorIndex];
}
}
}
_bgFifo.Pop();
_drawnPixels++;
if(_oamFifo.Size > 0) {
_oamFifo.Pop();
}
}
ClockTileFetcher();
}
void GbPpu::RunSpriteEvaluation()
{
if(_state.Cycle & 0x01) {
if(_spriteCount < 10) {
uint8_t spriteIndex = ((_state.Cycle - 4) >> 1) * 4;
int16_t sprY = _dmaController->IsOamDmaRunning() ? 0xFF : ((int16_t)_oam[spriteIndex] - 16);
if(_state.Scanline >= sprY && _state.Scanline < sprY + (_state.LargeSprites ? 16 : 8)) {
_spriteX[_spriteCount] = _oam[spriteIndex + 1];
_spriteIndexes[_spriteCount] = spriteIndex;
_spriteCount++;
}
}
} else {
//TODO check proper timing for even&odd cycles
}
}
void GbPpu::ResetRenderer()
{
//Reset fetcher & pixel FIFO
_oamFifo.Reset();
_oamFetcher.Step = 0;
_bgFifo.Reset();
_bgFifo.Size = 8;
_bgFetcher.Step = 0;
_drawnPixels = -8 - (_state.ScrollX & 0x07);
_fetchSprite = -1;
_fetchWindow = false;
_fetchColumn = _state.ScrollX / 8;
}
void GbPpu::ClockSpriteFetcher()
{
switch(_oamFetcher.Step++) {
case 1: {
//Fetch tile index
int16_t sprY = (int16_t)_oam[_fetchSprite] - 16;
uint8_t sprTile = _oam[_fetchSprite + 2];
uint8_t sprAttr = _oam[_fetchSprite + 3];
bool vMirror = (sprAttr & 0x40) != 0;
uint16_t tileBank = _state.CgbEnabled ? ((sprAttr & 0x08) ? 0x2000 : 0x0000) : 0;
uint8_t sprOffsetY = vMirror ? (_state.LargeSprites ? 15 : 7) - (_state.Scanline - sprY) : (_state.Scanline - sprY);
if(_state.LargeSprites) {
sprTile &= 0xFE;
}
uint16_t sprTileAddr = (sprTile * 16 + sprOffsetY * 2) | tileBank;
_oamFetcher.Addr = sprTileAddr;
_oamFetcher.Attributes = sprAttr;
break;
}
case 3: _oamFetcher.LowByte = _vram[_oamFetcher.Addr]; break;
case 5: {
//Fetch sprite data (high byte)
_oamFetcher.HighByte = _vram[_oamFetcher.Addr + 1];
PushSpriteToPixelFifo();
break;
}
}
}
void GbPpu::FindNextSprite()
{
if(_fetchSprite < 0 && (_state.SpritesEnabled || _state.CgbEnabled)) {
for(int i = 0; i < _spriteCount; i++) {
if((int)_spriteX[i] - 8 == _drawnPixels) {
_fetchSprite = _spriteIndexes[i];
_spriteX[i] = 0xFF; //Prevent processing the same sprite again
_oamFetcher.Step = 0;
break;
}
}
}
}
void GbPpu::ClockTileFetcher()
{
_evtColor = EvtColor::RenderingBgLoad;
switch(_bgFetcher.Step++) {
case 1: {
//Fetch tile index
uint16_t tilemapAddr;
uint8_t yOffset;
if(_fetchWindow) {
tilemapAddr = _state.WindowTilemapSelect ? 0x1C00 : 0x1800;
yOffset = (uint8_t)_windowCounter;
} else {
tilemapAddr = _state.BgTilemapSelect ? 0x1C00 : 0x1800;
yOffset = _state.ScrollY + _state.Scanline;
}
uint8_t row = yOffset >> 3;
uint16_t tileAddr = tilemapAddr + _fetchColumn + row * 32;
uint8_t tileIndex = _vram[tileAddr];
uint8_t attributes = _state.CgbEnabled ? _vram[tileAddr | 0x2000] : 0;
bool vMirror = (attributes & 0x40) != 0;
uint16_t tileBank = (attributes & 0x08) ? 0x2000 : 0x0000;
uint16_t baseTile = _state.BgTileSelect ? 0 : 0x1000;
uint8_t tileY = vMirror ? (7 - (yOffset & 0x07)) : (yOffset & 0x07);
uint16_t tileRowAddr = baseTile + (baseTile ? (int8_t)tileIndex * 16 : tileIndex * 16) + tileY * 2;
tileRowAddr |= tileBank;
_bgFetcher.Addr = tileRowAddr;
_bgFetcher.Attributes = (attributes & 0xBF);
break;
}
case 3: {
//Fetch tile data (low byte)
_bgFetcher.LowByte = _vram[_bgFetcher.Addr];
break;
}
case 5: {
//Fetch tile data (high byte)
_bgFetcher.HighByte = _vram[_bgFetcher.Addr + 1];
//Fallthrough
}
case 6:
case 7:
if(_bgFifo.Size == 0) {
PushTileToPixelFifo();
} else if(_bgFetcher.Step == 8) {
//Wait until fifo is empty to push pixels
_bgFetcher.Step = 7;
}
break;
}
}
void GbPpu::PushSpriteToPixelFifo()
{
_fetchSprite = -1;
_oamFetcher.Step = 0;
if(!_state.SpritesEnabled) {
return;
}
uint8_t pos = _oamFifo.Position;
//Overlap sprite
for(int i = 0; i < 8; i++) {
uint8_t shift = (_oamFetcher.Attributes & 0x20) ? i : (7 - i);
uint8_t bits = ((_oamFetcher.LowByte >> shift) & 0x01);
bits |= ((_oamFetcher.HighByte >> shift) & 0x01) << 1;
if(bits > 0 && _oamFifo.Content[pos].Color == 0) {
_oamFifo.Content[pos].Color = bits;
_oamFifo.Content[pos].Attributes = _oamFetcher.Attributes;
}
pos = (pos + 1) & 0x07;
}
_oamFifo.Size = 8;
}
void GbPpu::PushTileToPixelFifo()
{
//Add new tile to fifo
for(int i = 0; i < 8; i++) {
uint8_t shift = (_bgFetcher.Attributes & 0x20) ? i : (7 - i);
uint8_t bits = ((_bgFetcher.LowByte >> shift) & 0x01);
bits |= ((_bgFetcher.HighByte >> shift) & 0x01) << 1;
_bgFifo.Content[i].Color = (_state.CgbEnabled || _state.BgEnabled) ? bits : 0;
_bgFifo.Content[i].Attributes = _bgFetcher.Attributes;
}
_fetchColumn = (_fetchColumn + 1) & 0x1F;
_bgFifo.Position = 0;
_bgFifo.Size = 8;
_bgFetcher.Step = 0;
}
void GbPpu::UpdateStatIrq()
{
bool irqFlag = (
_state.LcdEnabled &&
((_state.LyCoincidenceFlag && (_state.Status & GbPpuStatusFlags::CoincidenceIrq)) ||
(_state.IrqMode == PpuMode::HBlank && (_state.Status & GbPpuStatusFlags::HBlankIrq)) ||
(_state.IrqMode == PpuMode::OamEvaluation && (_state.Status & GbPpuStatusFlags::OamIrq)) ||
(_state.IrqMode == PpuMode::VBlank && (_state.Status & GbPpuStatusFlags::VBlankIrq)))
);
if(irqFlag && !_state.StatIrqFlag) {
_memoryManager->RequestIrq(GbIrqSource::LcdStat);
}
_state.StatIrqFlag = irqFlag;
}
uint32_t GbPpu::GetFrameCount()
{
return _state.FrameCount;
}
uint8_t GbPpu::GetScanline()
{
return _state.Scanline;
}
uint16_t GbPpu::GetCycle()
{
return _state.Cycle;
}
bool GbPpu::IsLcdEnabled()
{
return _state.LcdEnabled;
}
bool GbPpu::IsCgbEnabled()
{
return _state.CgbEnabled;
}
PpuMode GbPpu::GetMode()
{
return _state.Mode;
}
void GbPpu::SendFrame()
{
_console->ProcessEvent(EventType::GbEndFrame);
_state.FrameCount++;
if(_gameboy->IsSgb()) {
return;
}
UpdatePalette();
_console->GetNotificationManager()->SendNotification(ConsoleNotificationType::PpuFrameDone);
if(_isFirstFrame) {
if(!_state.CgbEnabled) {
//Send blank frame on the first frame after enabling LCD (DMG only)
std::fill(_currentBuffer, _currentBuffer + 256 * 239, 0x7FFF);
} else {
//CGB repeats the previous frame?
uint16_t* src = _currentBuffer == _outputBuffers[0] ? _outputBuffers[1] : _outputBuffers[0];
std::copy(src, src + 256 * 239, _currentBuffer);
}
}
_isFirstFrame = false;
#ifdef LIBRETRO
_console->GetVideoDecoder()->UpdateFrameSync(_currentBuffer, 256, 239, _state.FrameCount, false);
#else
if(_console->GetRewindManager()->IsRewinding()) {
_console->GetVideoDecoder()->UpdateFrameSync(_currentBuffer, 256, 239, _state.FrameCount, true);
} else {
_console->GetVideoDecoder()->UpdateFrame(_currentBuffer, 256, 239, _state.FrameCount);
}
#endif
//TODO move this somewhere that makes more sense
uint8_t prevInput = _memoryManager->ReadInputPort();
_console->ProcessEndOfFrame();
uint8_t newInput = _memoryManager->ReadInputPort();
if(prevInput != newInput) {
_memoryManager->RequestIrq(GbIrqSource::Joypad);
}
_currentBuffer = _currentBuffer == _outputBuffers[0] ? _outputBuffers[1] : _outputBuffers[0];
}
void GbPpu::UpdatePalette()
{
if(!_gameboy->IsCgb()) {
GameboyConfig cfg = _console->GetSettings()->GetGameboyConfig();
for(int i = 0; i < 4; i++) {
//Set palette based on settings (DMG)
uint16_t bgColor = ((cfg.BgColors[i] & 0xF8) << 7) | ((cfg.BgColors[i] & 0xF800) >> 6) | ((cfg.BgColors[i] & 0xF80000) >> 19);
_state.CgbBgPalettes[i] = bgColor;
uint16_t obj0Color = ((cfg.Obj0Colors[i] & 0xF8) << 7) | ((cfg.Obj0Colors[i] & 0xF800) >> 6) | ((cfg.Obj0Colors[i] & 0xF80000) >> 19);
_state.CgbObjPalettes[i] = obj0Color;
uint16_t obj1Color = ((cfg.Obj1Colors[i] & 0xF8) << 7) | ((cfg.Obj1Colors[i] & 0xF800) >> 6) | ((cfg.Obj1Colors[i] & 0xF80000) >> 19);
_state.CgbObjPalettes[i + 4] = obj1Color;
}
}
}
uint8_t GbPpu::Read(uint16_t addr)
{
switch(addr) {
case 0xFF40: return _state.Control;
case 0xFF41:
//FF41 - STAT - LCDC Status (R/W)
return (
0x80 |
(_state.Status & 0x78) |
(_state.LyCoincidenceFlag ? 0x04 : 0x00) |
(int)_state.Mode
);
case 0xFF42: return _state.ScrollY; //FF42 - SCY - Scroll Y (R/W)
case 0xFF43: return _state.ScrollX; //FF43 - SCX - Scroll X (R/W)
case 0xFF44: return _state.Ly; //FF44 - LY - LCDC Y-Coordinate (R)
case 0xFF45: return _state.LyCompare; //FF45 - LYC - LY Compare (R/W)
case 0xFF47: return _state.BgPalette; //FF47 - BGP - BG Palette Data (R/W) - Non CGB Mode Only
case 0xFF48: return _state.ObjPalette0; //FF48 - OBP0 - Object Palette 0 Data (R/W) - Non CGB Mode Only
case 0xFF49: return _state.ObjPalette1; //FF49 - OBP1 - Object Palette 1 Data (R/W) - Non CGB Mode Only
case 0xFF4A: return _state.WindowY; //FF4A - WY - Window Y Position (R/W)
case 0xFF4B: return _state.WindowX; //FF4B - WX - Window X Position minus 7 (R/W)
}
LogDebug("[Debug] GB - Missing read handler: $" + HexUtilities::ToHex(addr));
return 0xFF;
}
void GbPpu::Write(uint16_t addr, uint8_t value)
{
switch(addr) {
case 0xFF40:
_state.Control = value;
if(_state.LcdEnabled != ((value & 0x80) != 0)) {
_state.LcdEnabled = (value & 0x80) != 0;
if(!_state.LcdEnabled) {
//Reset LCD to top of screen when it gets turned off
if(_state.Mode != PpuMode::VBlank) {
_console->BreakImmediately(BreakSource::GbDisableLcdOutsideVblank);
SendFrame();
}
_state.Cycle = 0;
_state.Scanline = 0;
_state.Ly = 0;
_state.LyForCompare = 0;
_state.Mode = PpuMode::HBlank;
_lastFrameTime = _gameboy->GetApuCycleCount();
//"If the HDMA started when the screen was on, when the screen is switched off it will copy one block after the switch."
_dmaController->ProcessHdma();
} else {
_isFirstFrame = true;
_state.Cycle = -1;
_state.IdleCycles = 0;
ResetRenderer();
_state.LyCoincidenceFlag = _state.LyCompare == _state.LyForCompare;
UpdateStatIrq();
}
}
_state.WindowTilemapSelect = (value & 0x40) != 0;
_state.WindowEnabled = (value & 0x20) != 0;
_state.BgTileSelect = (value & 0x10) != 0;
_state.BgTilemapSelect = (value & 0x08) != 0;
_state.LargeSprites = (value & 0x04) != 0;
_state.SpritesEnabled = (value & 0x02) != 0;
_state.BgEnabled = (value & 0x01) != 0;
break;
case 0xFF41:
if(!_gameboy->IsCgb()) {
//STAT write bug (DMG ONLY)
//Writing to STAT causes all IRQ types to be turned on for a single cycle
_state.Status = 0xF8 | (_state.Status & 0x07);
UpdateStatIrq();
}
_state.Status = value & 0xF8;
UpdateStatIrq();
break;
case 0xFF42: _state.ScrollY = value; break;
case 0xFF43: _state.ScrollX = value; break;
case 0xFF45:
_state.LyCompare = value;
if(_state.LcdEnabled) {
_state.IdleCycles = 0;
_state.LyCoincidenceFlag = (_state.LyCompare == _state.LyForCompare);
UpdateStatIrq();
}
break;
case 0xFF47: _state.BgPalette = value; break;
case 0xFF48: _state.ObjPalette0 = value; break;
case 0xFF49: _state.ObjPalette1 = value; break;
case 0xFF4A: _state.WindowY = value; break;
case 0xFF4B: _state.WindowX = value; break;
default:
LogDebug("[Debug] GB - Missing write handler: $" + HexUtilities::ToHex(addr));
break;
}
}
bool GbPpu::IsVramReadAllowed()
{
return _state.Mode <= PpuMode::VBlank || (_state.Mode == PpuMode::OamEvaluation && _state.Cycle < 80);
}
bool GbPpu::IsVramWriteAllowed()
{
return _state.Mode <= PpuMode::OamEvaluation;
}
uint8_t GbPpu::ReadVram(uint16_t addr)
{
if(IsVramReadAllowed()) {
uint16_t vramAddr = (_state.CgbVramBank << 13) | (addr & 0x1FFF);
_console->ProcessPpuRead(vramAddr, _vram[vramAddr], SnesMemoryType::GbVideoRam);
return _vram[vramAddr];
} else {
_console->BreakImmediately(BreakSource::GbInvalidVramAccess);
return 0xFF;
}
}
uint8_t GbPpu::PeekVram(uint16_t addr)
{
return IsVramReadAllowed() ? _vram[(_state.CgbVramBank << 13) | (addr & 0x1FFF)] : 0xFF;
}
void GbPpu::WriteVram(uint16_t addr, uint8_t value)
{
if(IsVramWriteAllowed()) {
uint16_t vramAddr = (_state.CgbVramBank << 13) | (addr & 0x1FFF);
_console->ProcessPpuWrite(vramAddr, value, SnesMemoryType::GbVideoRam);
_vram[vramAddr] = value;
} else {
_console->BreakImmediately(BreakSource::GbInvalidVramAccess);
}
}
bool GbPpu::IsOamWriteAllowed()
{
if(_memoryManager->IsOamDmaRunning()) {
return false;
}
if(_state.Scanline == 0 && _isFirstFrame) {
return _state.Mode == PpuMode::HBlank && _state.Cycle != 77 && _state.Cycle != 78;
} else {
return _state.Mode <= PpuMode::VBlank || (_state.Cycle >= 80 && _state.Cycle < 84);
}
}
bool GbPpu::IsOamReadAllowed()
{
if(_memoryManager->IsOamDmaRunning()) {
return false;
}
if(_state.Scanline == 0 && _isFirstFrame) {
return _state.Mode == PpuMode::HBlank;
} else {
return _state.Mode == PpuMode::VBlank || (_state.Mode == PpuMode::HBlank && _state.Cycle != 3);
}
}
uint8_t GbPpu::PeekOam(uint8_t addr)
{
if(addr < 0xA0) {
return IsOamReadAllowed() ? _oam[addr] : 0xFF;
}
return 0;
}
uint8_t GbPpu::ReadOam(uint8_t addr)
{
if(addr < 0xA0) {
if(IsOamReadAllowed()) {
_console->ProcessPpuRead(addr, _oam[addr], SnesMemoryType::GbSpriteRam);
return _oam[addr];
} else {
_console->BreakImmediately(BreakSource::GbInvalidOamAccess);
return 0xFF;
}
}
return 0;
}
void GbPpu::WriteOam(uint8_t addr, uint8_t value, bool forDma)
{
//During DMA or rendering/oam evaluation, ignore writes to OAM
//The DMA controller is always allowed to write to OAM (presumably the PPU can't read OAM during that time? TODO implement)
//On the DMG, there is a 4 clock gap (80 to 83) between OAM evaluation & rendering where writing is allowed
if(addr < 0xA0) {
if(forDma) {
_oam[addr] = value;
_console->ProcessPpuWrite(addr, value, SnesMemoryType::GbSpriteRam);
} else if(IsOamWriteAllowed()) {
_oam[addr] = value;
_console->ProcessPpuWrite(addr, value, SnesMemoryType::GbSpriteRam);
} else {
_console->BreakImmediately(BreakSource::GbInvalidOamAccess);
}
}
}
uint8_t GbPpu::ReadCgbRegister(uint16_t addr)
{
if(!_state.CgbEnabled) {
return 0xFF;
}
switch(addr) {
case 0xFF4F: return _state.CgbVramBank | 0xFE;
case 0xFF68: return _state.CgbBgPalPosition | (_state.CgbBgPalAutoInc ? 0x80 : 0) | 0x40;
case 0xFF69: return (_state.CgbBgPalettes[_state.CgbBgPalPosition >> 1] >> ((_state.CgbBgPalPosition & 0x01) ? 8 : 0) & 0xFF);
case 0xFF6A: return _state.CgbObjPalPosition | (_state.CgbObjPalAutoInc ? 0x80 : 0) | 0x40;
case 0xFF6B: return (_state.CgbObjPalettes[_state.CgbObjPalPosition >> 1] >> ((_state.CgbObjPalPosition & 0x01) ? 8 : 0) & 0xFF);
}
LogDebug("[Debug] GBC - Missing read handler: $" + HexUtilities::ToHex(addr));
return 0xFF;
}
void GbPpu::WriteCgbRegister(uint16_t addr, uint8_t value)
{
if(!_state.CgbEnabled && _memoryManager->IsBootRomDisabled()) {
return;
}
switch(addr) {
case 0xFF4C: _state.CgbEnabled = (value & 0x0C) == 0; break;
case 0xFF4F: _state.CgbVramBank = value & 0x01; break;
case 0xFF68:
//FF68 - BCPS/BGPI - CGB Mode Only - Background Palette Index
_state.CgbBgPalPosition = value & 0x3F;
_state.CgbBgPalAutoInc = (value & 0x80) != 0;
break;
case 0xFF69: {
//FF69 - BCPD/BGPD - CGB Mode Only - Background Palette Data
WriteCgbPalette(_state.CgbBgPalPosition, _state.CgbBgPalettes, _state.CgbBgPalAutoInc, value);
break;
}
case 0xFF6A:
//FF6A - OCPS/OBPI - CGB Mode Only - Sprite Palette Index
_state.CgbObjPalPosition = value & 0x3F;
_state.CgbObjPalAutoInc = (value & 0x80) != 0;
break;
case 0xFF6B:
//FF6B - OCPD/OBPD - CGB Mode Only - Sprite Palette Data
WriteCgbPalette(_state.CgbObjPalPosition, _state.CgbObjPalettes, _state.CgbObjPalAutoInc, value);
break;
default:
LogDebug("[Debug] GBC - Missing write handler: $" + HexUtilities::ToHex(addr));
break;
}
}
void GbPpu::WriteCgbPalette(uint8_t& pos, uint16_t* pal, bool autoInc, uint8_t value)
{
if(_state.Mode <= PpuMode::OamEvaluation) {
if(pos & 0x01) {
pal[pos >> 1] = (pal[pos >> 1] & 0xFF) | ((value & 0x7F) << 8);
} else {
pal[pos >> 1] = (pal[pos >> 1] & 0xFF00) | value;
}
}
if(autoInc) {
pos = (pos + 1) & 0x3F;
}
}
void GbPpu::Serialize(Serializer& s)
{
s.Stream(
_state.Scanline, _state.Cycle, _state.Mode, _state.LyCompare, _state.BgPalette, _state.ObjPalette0, _state.ObjPalette1,
_state.ScrollX, _state.ScrollY, _state.WindowX, _state.WindowY, _state.Control, _state.LcdEnabled, _state.WindowTilemapSelect,
_state.WindowEnabled, _state.BgTileSelect, _state.BgTilemapSelect, _state.LargeSprites, _state.SpritesEnabled, _state.BgEnabled,
_state.Status, _state.FrameCount, _lastFrameTime, _state.LyCoincidenceFlag,
_state.CgbBgPalAutoInc, _state.CgbBgPalPosition,
_state.CgbObjPalAutoInc, _state.CgbObjPalPosition, _state.CgbVramBank, _state.CgbEnabled,
_latchWindowX, _latchWindowY, _latchWindowEnabled, _windowCounter, _isFirstFrame, _rendererIdle,
_state.IdleCycles, _state.Ly, _state.LyForCompare, _state.IrqMode
);
s.StreamArray(_state.CgbBgPalettes, 4 * 8);
s.StreamArray(_state.CgbObjPalettes, 4 * 8);
s.Stream(
_bgFetcher.Attributes, _bgFetcher.Step, _bgFetcher.Addr, _bgFetcher.LowByte, _bgFetcher.HighByte,
_oamFetcher.Attributes, _oamFetcher.Step, _oamFetcher.Addr, _oamFetcher.LowByte, _oamFetcher.HighByte,
_drawnPixels, _fetchColumn, _fetchWindow, _fetchSprite, _spriteCount,
_bgFifo.Position, _bgFifo.Size, _oamFifo.Position, _oamFifo.Size
);
for(int i = 0; i < 8; i++) {
s.Stream(_bgFifo.Content[i].Color, _bgFifo.Content[i].Attributes);
s.Stream(_oamFifo.Content[i].Color, _oamFifo.Content[i].Attributes);
}
s.StreamArray(_spriteX, 10);
s.StreamArray(_spriteIndexes, 10);
}