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instruction.rs: Add edge wrapping for draw_lores_sprite, and fix the Last Byte Bug

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John 2023-04-17 05:15:12 -05:00
parent 401b247c05
commit 1573e00928
1 changed files with 19 additions and 10 deletions
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29
src/cpu/instruction.rs
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@ -339,16 +339,25 @@ impl CPU {
let sprite = sprite.to_vec();
for (line, &sprite) in sprite.iter().enumerate() {
let line = line as u16;
if y + line >= h {
break;
}
let sprite = (sprite as u16) << (8 - (x % 8))
& if (x % w) >= (w - 8) { 0xff00 } else { 0xffff };
let addr = |x, y| -> u16 { (y + line) * w_bytes + (x / 8) + self.screen };
let screen: u16 = bus.read(addr(x, y));
bus.write(addr(x, y), screen ^ sprite);
if screen & sprite != 0 {
self.v[0xf] = 1;
let sprite = ((sprite as u16) << (8 - (x % 8))).to_be_bytes();
for (addr, &byte) in sprite.iter().enumerate().filter_map(|(idx, byte)| {
let x = (x / 8) + idx as u16;
Some((
if self.flags.quirks.screen_wrap {
((y + line) % h * w_bytes + (x % w_bytes)) % (w_bytes * h)
} else if x < w_bytes {
(y + line) * w_bytes + x
} else {
return None;
} + self.screen,
byte,
))
}) {
let screen: u8 = bus.read(addr);
bus.write(addr, byte ^ screen);
if byte & screen != 0 {
self.v[0xf] = 1;
}
}
}
}