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Small PPU tweaks - fixes a couple of tests

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This commit is contained in:
Souryo 2015-07-24 19:20:54 -04:00
parent 068fa72e87
commit b16ddd399d
1 changed files with 15 additions and 13 deletions
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28
Core/PPU.cpp
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@ -28,7 +28,7 @@ void PPU::Reset()
_statusFlags = {};
_scanline = 0;
_cycle = 0;
_cycle = -1;
_frameCount = 0;
_memoryReadBuffer = 0;
@ -205,7 +205,7 @@ void PPU::SetControlRegister(uint8_t value)
bool originalVBlank = _flags.VBlank;
_flags.VBlank = (_state.Control & 0x80) == 0x80;
if(!originalVBlank && _flags.VBlank && _statusFlags.VerticalBlank) {
if(!originalVBlank && _flags.VBlank && _statusFlags.VerticalBlank && (_scanline != -1 || _cycle != 0)) {
CPU::SetNMIFlag();
} else if(_scanline == 241 && _cycle < 3 && !_flags.VBlank) {
CPU::ClearNMIFlag();
@ -246,9 +246,11 @@ void PPU::UpdateStatusFlag()
if(_scanline == 241) {
if(_cycle < 3) {
//"Reading on the same PPU clock or one later reads it as set, clears it, and suppresses the NMI for that frame."
CPU::ClearNMIFlag();
if(_cycle == 0) {
//"Reading one PPU clock before reads it as clear and never sets the flag or generates NMI for that frame. "
_doNotSetVBFlag = true;
}
}
@ -468,7 +470,7 @@ void PPU::ProcessPrerenderScanline()
{
ProcessPreVBlankScanline();
if(_cycle == 0) {
if(_cycle == 1) {
_statusFlags.SpriteOverflow = false;
_statusFlags.Sprite0Hit = false;
_statusFlags.VerticalBlank = false;
@ -604,7 +606,7 @@ void PPU::CopyOAMData()
void PPU::BeginVBlank()
{
if(_cycle == 0) {
if(_cycle == 1) {
//Send frame to GUI once the last pixel has been output
if(PPU::VideoDevice) {
PPU::VideoDevice->UpdateFrame(_outputBuffer);
@ -629,6 +631,15 @@ void PPU::EndVBlank()
void PPU::Exec()
{
if(_cycle == 340) {
_cycle = -1;
if(_scanline++ == _vblankEnd) {
_scanline = -1;
}
}
_cycle++;
if(_scanline != -1 && _scanline < 240) {
ProcessVisibleScanline();
} else if(_scanline == -1) {
@ -638,15 +649,6 @@ void PPU::Exec()
} else if(_scanline == _vblankEnd) {
EndVBlank();
}
if(_cycle == 340) {
_cycle = -1;
if(_scanline++ == _vblankEnd) {
_scanline = -1;
}
}
_cycle++;
}
void PPU::ExecStatic()