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dyncom: Read-after-write in SMLA 

In the case when RD === RN, RD was updated before AddOverflow was called
to check for an overflow, resulting in an incorrect state of the Q flag.
This commit is contained in:
MerryMage 2016-08-22 15:06:35 +01:00
parent 7b4dcacbb2
commit 15b2eec4bd
1 changed files with 4 additions and 2 deletions
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6
src/core/arm/dyncom/arm_dyncom_interpreter.cpp
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@ -2820,10 +2820,12 @@ unsigned InterpreterMainLoop(ARMul_State* cpu) {
operand2 = (BIT(RS, 15)) ? (BITS(RS, 0, 15) | 0xffff0000) : BITS(RS, 0, 15);
else
operand2 = (BIT(RS, 31)) ? (BITS(RS, 16, 31) | 0xffff0000) : BITS(RS, 16, 31);
RD = operand1 * operand2 + RN;
if (AddOverflow(operand1 * operand2, RN, RD))
u32 product = operand1 * operand2;
u32 result = product + RN;
if (AddOverflow(product, RN, result))
cpu->Cpsr |= (1 << 27);
RD = result;
}
cpu->Reg[15] += cpu->GetInstructionSize();
INC_PC(sizeof(smla_inst));