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added RulePositiveDiv

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This commit is contained in:
caheckman 2019-10-23 16:38:35 -04:00
parent 165377aad7
commit 992d32dd87
3 changed files with 39 additions and 0 deletions
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27
Ghidra/Features/Decompiler/src/decompile/cpp/ruleaction.cc
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@ -6448,6 +6448,33 @@ int4 RuleSubNormal::applyOp(PcodeOp *op,Funcdata &data)
return 1;
}
/// \class RulePositiveDiv
/// \brief Signed division of positive values is unsigned division
///
/// If the sign bit of both the numerator and denominator of a signed division (or remainder)
/// are zero, then convert to the unsigned form of the operation.
void RulePositiveDiv::getOpList(vector<uint4> &oplist) const
{
oplist.push_back(CPUI_INT_SDIV);
oplist.push_back(CPUI_INT_SREM);
}
int4 RulePositiveDiv::applyOp(PcodeOp *op,Funcdata &data)
{
int4 sa = op->getOut()->getSize();
if (sa > sizeof(uintb)) return 0;
sa = sa * 8 - 1;
if (((op->getIn(0)->getNZMask() >> sa) & 1) != 0)
return 0; // Input 0 may be negative
if (((op->getIn(1)->getNZMask() >> sa) & 1) != 0)
return 0; // Input 1 may be negative
OpCode opc = (op->code() == CPUI_INT_SDIV) ? CPUI_INT_DIV : CPUI_INT_REM;
data.opSetOpcode(op, opc);
return 1;
}
/// \class RuleDivTermAdd
/// \brief Simplify expressions associated with optimized division expressions
///