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OpcodeDispatcher: optimize JA/JNA

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Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
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Alyssa Rosenzweig committed 2024-08-10 13:06:42 -04:00
1 parent 3bb9d44bf5
commit f138d7d9b8
2 files changed
+13 -14
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FEXCore/Source/Interface/Core/OpcodeDispatcher.cpp
+12 -13
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@@ -702,7 +702,7 @@ Ref OpDispatchBuilder::SelectBit(Ref Cmp, IR::OpSize ResultSize, Ref TrueValue,
return _NZCVSelect(ResultSize, {COND_NEQ}, TrueValue, FalseValue);
}
std::pair<bool, CondClassType> OpDispatchBuilder::DecodeNZCVCondition(uint8_t OP) const {
std::pair<bool, CondClassType> OpDispatchBuilder::DecodeNZCVCondition(uint8_t OP) {
switch (OP) {
case 0x0: { // JO - Jump if OF == 1
return {false, CondClassType {COND_FU}};
@@ -722,6 +722,17 @@ std::pair<bool, CondClassType> OpDispatchBuilder::DecodeNZCVCondition(uint8_t OP
case 0x5: { // JNE - Jump if ZF == 0
return {false, CondClassType {COND_NEQ}};
}
case 0x6: { // JNA - Jump if CF == 1 || ZF == 1
// With CF, we want (C == 0 || Z == 1). By De Morgan's, that's
// equivalent to !(C == 1 && Z == 0). That's .ls
RectifyCarryInvert(true);
return {false, CondClassType {COND_ULE}};
}
case 0x7: { // JA - Jump if CF == 0 && ZF == 0
// With CF inverted, we want (C == 1 && Z == 0). That's .hi
RectifyCarryInvert(true);
return {false, CondClassType {COND_UGT}};
}
case 0x8: { // JS - Jump if SF == 1
return {false, CondClassType {COND_MI}};
}
@@ -754,18 +765,6 @@ Ref OpDispatchBuilder::SelectCC(uint8_t OP, IR::OpSize ResultSize, Ref TrueValue
}
switch (OP) {
case 0x6: { // JNA - Jump if CF == 1 || ZC == 1
// (A || B) ? C : D is equivalent to B ? C : (A ? C : D)
// TODO: Optimize
auto TMP = NZCVSelect(ResultSize, {COND_UGE}, TrueValue, FalseValue, false);
return NZCVSelect(ResultSize, {COND_EQ}, TrueValue, TMP, false);
}
case 0x7: { // JA - Jump if CF == 0 && ZF == 0
// (A && B) ? C : D is equivalent to B ? (A ? C : D) : D
// TODO: Optimize
auto TMP = NZCVSelect(ResultSize, CondClassType {COND_ULT}, TrueValue, FalseValue, false);
return NZCVSelect(ResultSize, CondClassType {COND_NEQ}, TMP, FalseValue, false);
}
case 0xA: { // JP - Jump if PF == 1
// Raw value contains inverted PF in bottom bit
return SelectBit(LoadPFRaw(true), ResultSize, TrueValue, FalseValue);