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ARM: Implement the saturation instructions.

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This commit is contained in:
Gabe Black 2010-06-02 12:58:06 -05:00
parent c96f03a250
commit 61b8e33225
2 changed files with 109 additions and 4 deletions
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39
src/arch/arm/insts/static_inst.hh
View file

@ -67,9 +67,9 @@ class ArmStaticInst : public StaticInst
int64_t midRes = sub ? (op1 - op2) : (op1 + op2);
if (bits(midRes, width) != bits(midRes, width - 1)) {
if (midRes > 0)
res = (1LL << (width - 1)) - 1;
res = (LL(1) << (width - 1)) - 1;
else
res = -(1LL << (width - 1));
res = -(LL(1) << (width - 1));
return true;
} else {
res = midRes;
@ -77,13 +77,29 @@ class ArmStaticInst : public StaticInst
}
}
static bool
satInt(int32_t &res, int64_t op, int width)
{
width--;
if (op >= (LL(1) << width)) {
res = (LL(1) << width) - 1;
return true;
} else if (op < -(LL(1) << width)) {
res = -(LL(1) << width);
return true;
} else {
res = op;
return false;
}
}
template<int width>
static bool
uSaturateOp(uint32_t &res, int64_t op1, int64_t op2, bool sub=false)
{
int64_t midRes = sub ? (op1 - op2) : (op1 + op2);
if (midRes >= (1 << width)) {
res = (1 << width) - 1;
if (midRes >= (LL(1) << width)) {
res = (LL(1) << width) - 1;
return true;
} else if (midRes < 0) {
res = 0;
@ -94,6 +110,21 @@ class ArmStaticInst : public StaticInst
}
}
static bool
uSatInt(int32_t &res, int64_t op, int width)
{
if (op >= (LL(1) << width)) {
res = (LL(1) << width) - 1;
return true;
} else if (op < 0) {
res = 0;
return true;
} else {
res = op;
return false;
}
}
// Constructor
ArmStaticInst(const char *mnem, ExtMachInst _machInst,
OpClass __opClass)

74
src/arch/arm/isa/insts/misc.isa
View file

@ -153,4 +153,78 @@ let {{
header_output += RevOpDeclare.subst(revshIop)
decoder_output += RevOpConstructor.subst(revshIop)
exec_output += PredOpExecute.subst(revshIop)
ssatCode = '''
int32_t operand = shift_rm_imm(Op1, shiftAmt, shiftType, 0);
int32_t res;
if (satInt(res, operand, satImm))
CondCodes = CondCodes | (1 << 27);
else
CondCodes = CondCodes;
Dest = res;
'''
ssatIop = InstObjParams("ssat", "Ssat", "SatShiftOp",
{ "code": ssatCode,
"predicate_test": predicateTest }, [])
header_output += SatShiftOpDeclare.subst(ssatIop)
decoder_output += SatShiftOpConstructor.subst(ssatIop)
exec_output += PredOpExecute.subst(ssatIop)
usatCode = '''
int32_t operand = shift_rm_imm(Op1, shiftAmt, shiftType, 0);
int32_t res;
if (uSatInt(res, operand, satImm))
CondCodes = CondCodes | (1 << 27);
else
CondCodes = CondCodes;
Dest = res;
'''
usatIop = InstObjParams("usat", "Usat", "SatShiftOp",
{ "code": usatCode,
"predicate_test": predicateTest }, [])
header_output += SatShiftOpDeclare.subst(usatIop)
decoder_output += SatShiftOpConstructor.subst(usatIop)
exec_output += PredOpExecute.subst(usatIop)
ssat16Code = '''
int32_t res;
uint32_t resTemp = 0;
CondCodes = CondCodes;
int32_t argLow = sext<16>(bits(Op1, 15, 0));
int32_t argHigh = sext<16>(bits(Op1, 31, 16));
if (satInt(res, argLow, satImm))
CondCodes = CondCodes | (1 << 27);
replaceBits(resTemp, 15, 0, res);
if (satInt(res, argHigh, satImm))
CondCodes = CondCodes | (1 << 27);
replaceBits(resTemp, 31, 16, res);
Dest = resTemp;
'''
ssat16Iop = InstObjParams("ssat16", "Ssat16", "SatOp",
{ "code": ssat16Code,
"predicate_test": predicateTest }, [])
header_output += SatOpDeclare.subst(ssat16Iop)
decoder_output += SatOpConstructor.subst(ssat16Iop)
exec_output += PredOpExecute.subst(ssat16Iop)
usat16Code = '''
int32_t res;
uint32_t resTemp = 0;
CondCodes = CondCodes;
int32_t argLow = sext<16>(bits(Op1, 15, 0));
int32_t argHigh = sext<16>(bits(Op1, 31, 16));
if (uSatInt(res, argLow, satImm))
CondCodes = CondCodes | (1 << 27);
replaceBits(resTemp, 15, 0, res);
if (uSatInt(res, argHigh, satImm))
CondCodes = CondCodes | (1 << 27);
replaceBits(resTemp, 31, 16, res);
Dest = resTemp;
'''
usat16Iop = InstObjParams("usat16", "Usat16", "SatOp",
{ "code": usat16Code,
"predicate_test": predicateTest }, [])
header_output += SatOpDeclare.subst(usat16Iop)
decoder_output += SatOpConstructor.subst(usat16Iop)
exec_output += PredOpExecute.subst(usat16Iop)
}};