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CPU: BIT with immediate addressing should not alter V/N flags

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Sour 2019-02-14 00:49:34 -05:00
parent 0f64559882
commit 3cf0b0e46d
1 changed files with 20 additions and 9 deletions
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29
Core/Cpu.Instructions.cpp
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@ -801,15 +801,26 @@ Bit test operations
********************/ ********************/
template<typename T> void Cpu::TestBits(T value) template<typename T> void Cpu::TestBits(T value)
{ {
ClearFlags(ProcFlags::Zero | ProcFlags::Overflow | ProcFlags::Negative); if(_instAddrMode <= AddrMode::ImmM) {
if(((T)_state.A & value) == 0) { //"Immediate addressing only affects the z flag (with the result of the bitwise And), but does not affect the n and v flags."
SetFlags(ProcFlags::Zero); if(((T)_state.A & value) == 0) {
} SetFlags(ProcFlags::Zero);
if(value & (1 << (sizeof(T) * 8 - 2))) { } else {
SetFlags(ProcFlags::Overflow); ClearFlags(ProcFlags::Zero);
} }
if(value & (1 << (sizeof(T) * 8 - 1))) { } else {
SetFlags(ProcFlags::Negative); ClearFlags(ProcFlags::Zero | ProcFlags::Overflow | ProcFlags::Negative);
if(((T)_state.A & value) == 0) {
SetFlags(ProcFlags::Zero);
}
if(value & (1 << (sizeof(T) * 8 - 2))) {
SetFlags(ProcFlags::Overflow);
}
if(value & (1 << (sizeof(T) * 8 - 1))) {
SetFlags(ProcFlags::Negative);
}
} }
} }