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Simplify parity logic.

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This commit is contained in:
Thomas Harte 2023-10-07 13:38:36 -04:00
parent 16bf7c6f26
commit 5c62606154
1 changed files with 5 additions and 6 deletions

11
InstructionSets/x86/Status.hpp

@ -71,14 +71,13 @@ struct Status {
// Flag getters.
template <typename IntT> IntT carry_bit() const { return carry ? 1 : 0; }
bool parity_bit() const {
uint32_t result = parity;
result ^= result >> 16;
result ^= result >> 8;
bool not_parity_bit() const {
// x86 parity always considers the lowest 8-bits only.
auto result = static_cast<uint8_t>(parity);
result ^= result >> 4;
result ^= result >> 2;
result ^= result >> 1;
return 1 ^ (result & 1);
return result & 1;
}
// Complete value get and set.
@ -110,7 +109,7 @@ struct Status {
(zero ? 0 : ConditionCode::Zero) |
(parity_bit() ? ConditionCode::Parity : 0);
(not_parity_bit() ? 0 : ConditionCode::Parity);
}
bool operator ==(const Status &rhs) const {