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Emulator: Fix pixel FIFO fetcher half step speed

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Riyyi
2022-10-17 15:58:12 +02:00
parent 00ceacaf52
commit 1c14228bf7
1 changed files with 13 additions and 11 deletions
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src/ppu.cpp
+13 -11
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@@ -146,7 +146,10 @@ void PPU::pixelFifo()
switch (m_pixel_fifo.state) {
case PixelFifo::State::TileIndex:
if (m_pixel_fifo.step == true) {
if (!m_pixel_fifo.step) {
m_pixel_fifo.step = true;
}
else {
m_pixel_fifo.step = false;
m_pixel_fifo.state = PixelFifo::State::TileDataLow;
@@ -164,11 +167,12 @@ void PPU::pixelFifo()
// Set the tile line we're currently on
m_pixel_fifo.tile_line = (m_viewport_y + m_lcd_y_coordinate) % TILE_HEIGHT;
}
m_pixel_fifo.step = true;
break;
case PixelFifo::State::TileDataLow:
if (m_pixel_fifo.step == true) {
if (!m_pixel_fifo.step) {
m_pixel_fifo.step = true;
}
else {
m_pixel_fifo.step = false;
m_pixel_fifo.state = PixelFifo::State::TileDataHigh;
@@ -177,11 +181,12 @@ void PPU::pixelFifo()
+ (m_pixel_fifo.tile_index * TILE_SIZE) // Each tile is 16 bytes
+ m_pixel_fifo.tile_line * 2); // Each tile line is 2 bytes
}
m_pixel_fifo.step = true;
break;
case PixelFifo::State::TileDataHigh:
if (m_pixel_fifo.step == true) {
if (!m_pixel_fifo.step) {
m_pixel_fifo.step = true;
}
else {
m_pixel_fifo.step = false;
m_pixel_fifo.state = PixelFifo::State::Sleep;
@@ -191,15 +196,13 @@ void PPU::pixelFifo()
+ m_pixel_fifo.tile_line * 2
+ 1);
}
m_pixel_fifo.step = true;
break;
case PixelFifo::State::Sleep:
if (m_pixel_fifo.background.size() <= 9) {
m_pixel_fifo.state = PixelFifo::State::Push;
}
break;
case PixelFifo::State::Push: {
case PixelFifo::State::Push:
m_pixel_fifo.state = PixelFifo::State::TileIndex;
for (uint8_t i = 0; i < 8; ++i) {
@@ -209,7 +212,6 @@ void PPU::pixelFifo()
m_pixel_fifo.background.push({ color_index, Palette::BGP });
}
break;
}
default:
VERIFY_NOT_REACHED();
};