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saturated: Implement SSAT16 and USAT16

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This commit is contained in:
MerryMage 2017-02-18 17:43:57 +00:00
parent 358cf7c322
commit cc9d2c4603
1 changed files with 41 additions and 4 deletions
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45
src/frontend/translate/translate_arm/saturated.cpp
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@ -9,6 +9,14 @@
namespace Dynarmic {
namespace Arm {
static IR::Value Pack2x16To1x32(IR::IREmitter& ir, IR::Value lo, IR::Value hi) {
return ir.Or(ir.And(lo, ir.Imm32(0xFFFF)), ir.LogicalShiftLeft(hi, ir.Imm8(16), ir.Imm1(0)).result);
}
static IR::Value MostSignificantHalf(IR::IREmitter& ir, IR::Value value) {
return ir.LeastSignificantHalf(ir.LogicalShiftRight(value, ir.Imm8(16), ir.Imm1(0)).result);
}
// Saturation instructions
bool ArmTranslatorVisitor::arm_SSAT(Cond cond, Imm5 sat_imm, Reg d, Imm5 imm5, bool sh, Reg n) {
@ -29,8 +37,22 @@ bool ArmTranslatorVisitor::arm_SSAT(Cond cond, Imm5 sat_imm, Reg d, Imm5 imm5, b
}
bool ArmTranslatorVisitor::arm_SSAT16(Cond cond, Imm4 sat_imm, Reg d, Reg n) {
UNUSED(cond, sat_imm, d, n);
return InterpretThisInstruction();
if (d == Reg::PC || n == Reg::PC)
return UnpredictableInstruction();
size_t saturate_to = static_cast<size_t>(sat_imm) + 1;
// SSAT16 <Rd>, #<saturate_to>, <Rn>
if (ConditionPassed(cond)) {
auto lo_operand = ir.SignExtendHalfToWord(ir.LeastSignificantHalf(ir.GetRegister(n)));
auto hi_operand = ir.SignExtendHalfToWord(MostSignificantHalf(ir, ir.GetRegister(n)));
auto lo_result = ir.SignedSaturation(lo_operand, saturate_to);
auto hi_result = ir.SignedSaturation(hi_operand, saturate_to);
ir.SetRegister(d, Pack2x16To1x32(ir, lo_result.result, hi_result.result));
ir.OrQFlag(lo_result.overflow);
ir.OrQFlag(hi_result.overflow);
}
return true;
}
bool ArmTranslatorVisitor::arm_USAT(Cond cond, Imm5 sat_imm, Reg d, Imm5 imm5, bool sh, Reg n) {
@ -51,8 +73,23 @@ bool ArmTranslatorVisitor::arm_USAT(Cond cond, Imm5 sat_imm, Reg d, Imm5 imm5, b
}
bool ArmTranslatorVisitor::arm_USAT16(Cond cond, Imm4 sat_imm, Reg d, Reg n) {
UNUSED(cond, sat_imm, d, n);
return InterpretThisInstruction();
if (d == Reg::PC || n == Reg::PC)
return UnpredictableInstruction();
size_t saturate_to = static_cast<size_t>(sat_imm);
// USAT16 <Rd>, #<saturate_to>, <Rn>
if (ConditionPassed(cond)) {
// UnsignedSaturation takes a *signed* value as input, hence sign extension is required.
auto lo_operand = ir.SignExtendHalfToWord(ir.LeastSignificantHalf(ir.GetRegister(n)));
auto hi_operand = ir.SignExtendHalfToWord(MostSignificantHalf(ir, ir.GetRegister(n)));
auto lo_result = ir.UnsignedSaturation(lo_operand, saturate_to);
auto hi_result = ir.UnsignedSaturation(hi_operand, saturate_to);
ir.SetRegister(d, Pack2x16To1x32(ir, lo_result.result, hi_result.result));
ir.OrQFlag(lo_result.overflow);
ir.OrQFlag(hi_result.overflow);
}
return true;
}
// Saturated Add/Subtract instructions