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x86: Fix x87 state transfer bug

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Changeset 7274310be1bb (isa: clean up register constants) increased
the value of NumFloatRegs, which triggered a bug in
X86ISA::copyRegs(). This bug is caused by the x87 stack being copied
twice since register indexes past NUM_FLOATREGS are mapped into the
x87 stack relative to the top of the stack, which is undefined when
the copy takes place.

This changeset updates the copyRegs() function to use access registers
using the non-flattening interface, which guarantees that undesirable
register folding does not happen.
This commit is contained in:
Andreas Sandberg 2014-02-05 14:08:13 +01:00
parent c6279f2d19
commit e76a37985f
1 changed files with 3 additions and 3 deletions
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6
src/arch/x86/utility.cc
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@ -240,13 +240,13 @@ copyRegs(ThreadContext *src, ThreadContext *dest)
{
//copy int regs
for (int i = 0; i < NumIntRegs; ++i)
dest->setIntReg(i, src->readIntReg(i));
dest->setIntRegFlat(i, src->readIntRegFlat(i));
//copy float regs
for (int i = 0; i < NumFloatRegs; ++i)
dest->setFloatRegBits(i, src->readFloatRegBits(i));
dest->setFloatRegBitsFlat(i, src->readFloatRegBitsFlat(i));
//copy condition-code regs
for (int i = 0; i < NumCCRegs; ++i)
dest->setCCReg(i, src->readCCReg(i));
dest->setCCRegFlat(i, src->readCCRegFlat(i));
copyMiscRegs(src, dest);
dest->pcState(src->pcState());
}