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decrement_x_test passes

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This commit is contained in:
Sam M W 2022-10-20 09:22:26 +01:00
parent 1972a42adc
commit c406965560
1 changed files with 20 additions and 2 deletions
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22
src/cpu.rs
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@ -648,6 +648,23 @@ impl CPU {
self.load_accumulator(result);
}
fn decrement(&mut self, val: &mut u8) {
let value_new = val.wrapping_sub(1);
*val = value_new;
let is_negative = (value_new as i8) < 0;
let is_zero = value_new == 0;
self.registers.status.set_with_mask(
Status::PS_NEGATIVE | Status::PS_ZERO,
Status::new(StatusArgs {
negative: is_negative,
zero: is_zero,
..StatusArgs::none()
}),
);
}
fn decrement_memory(&mut self, addr: Address) {
let value_new = self.memory.get_byte(addr).wrapping_sub(1);
@ -667,8 +684,9 @@ impl CPU {
}
fn dec_x(&mut self) {
let val = self.registers.index_x;
self.load_x_register(val - 1);
let mut r = u8::from_ne_bytes(self.registers.index_x.to_ne_bytes());
self.decrement(&mut r);
self.load_x_register(i8::from_ne_bytes(r.to_ne_bytes()));
}
fn jump(&mut self, addr: Address) {