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fix: properly implement LY==LYC behaviour

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This commit is contained in:
Rekai Nyangadzayi Musuka
2021-05-05 08:29:39 -05:00
parent b36f4441fa
commit abdff1251e
3 changed files with 35 additions and 22 deletions
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28
src/ppu.rs
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@@ -103,10 +103,13 @@ impl Ppu {
self.cycles %= 456;
self.pos.line_y += 1;
// New Scanline is next, check for LYC=LY
if self.stat.coincidence_int() {
let are_equal = self.pos.line_y == self.pos.ly_compare;
self.stat.set_coincidence(are_equal);
// Update LY==LYC bit
let are_equal = self.pos.line_y == self.pos.ly_compare;
self.stat.set_coincidence(are_equal);
// Request LCD STAT interrupt if conditions met
if self.stat.coincidence_int() && are_equal {
self.int.set_lcd_stat(true);
}
let next_mode = if self.pos.line_y >= 144 {
@@ -140,10 +143,13 @@ impl Ppu {
self.cycles %= 456;
self.pos.line_y += 1;
// New Scanline is next, check for LYC=LY
if self.stat.coincidence_int() {
let are_equal = self.pos.line_y == self.pos.ly_compare;
self.stat.set_coincidence(are_equal);
// Update LY==LYC bit
let are_equal = self.pos.line_y == self.pos.ly_compare;
self.stat.set_coincidence(are_equal);
// Request LCD STAT interrupt if conditions met
if self.stat.coincidence_int() && are_equal {
self.int.set_lcd_stat(true);
}
if self.pos.line_y == 154 {
@@ -687,8 +693,8 @@ impl PixelFetcher {
let id = self.bg.tile.id.expect("Tile Number unexpectedly missing");
let tile_data_addr = match control.tile_data_addr() {
TileDataAddress::X8800 => 0x9000u16.wrapping_add((id as i8 * 16) as u16),
TileDataAddress::X8000 => 0x8000 + (id as u16 * 16),
TileDataAddress::X8800 => 0x9000u16.wrapping_add((id as i8).wrapping_mul(16) as u16),
TileDataAddress::X8000 => 0x8000 + (id as u16).wrapping_mul(16),
};
let offset = 2 * if window {
@@ -737,7 +743,7 @@ impl PixelFetcher {
(line_y + scroll_y) % 8
};
0x8000 + (attr.tile_index as u16 * 16) + offset as u16
0x8000 + (tile_number as u16 * 16) + offset as u16
}
}