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fix DAA

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This commit is contained in:
Alex Janka 2023-02-09 17:30:50 +11:00
parent 615446faa7
commit b659e5c77b
1 changed files with 4 additions and 4 deletions
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8
src/processor/opcodes.rs
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@ -188,19 +188,19 @@ impl CPU {
if !self.is_flag(Flags::NSubtract) { if !self.is_flag(Flags::NSubtract) {
// after an addition, adjust if (half-)carry occurred or if result is out of bounds // after an addition, adjust if (half-)carry occurred or if result is out of bounds
if self.is_flag(Flags::Carry) || a > 0x99 { if self.is_flag(Flags::Carry) || a > 0x99 {
a += 0x60; a = a.wrapping_add(0x60);
self.set_flag(Flags::Carry); self.set_flag(Flags::Carry);
} }
if self.is_flag(Flags::HalfCarry) || (a & 0x0f) > 0x09 { if self.is_flag(Flags::HalfCarry) || (a & 0x0f) > 0x09 {
a += 0x6; a = a.wrapping_add(0x6);
} }
} else { } else {
// after a subtraction, only adjust if (half-)carry occurred // after a subtraction, only adjust if (half-)carry occurred
if self.is_flag(Flags::Carry) { if self.is_flag(Flags::Carry) {
a -= 0x60; a = a.wrapping_sub(0x60);
} }
if self.is_flag(Flags::HalfCarry) { if self.is_flag(Flags::HalfCarry) {
a -= 0x6; a = a.wrapping_sub(0x6);
} }
} }
// these flags are always updated // these flags are always updated