From ca96e7bff1dfaa8e0a6d900feb88c711198b4b2b Mon Sep 17 00:00:00 2001 From: Geoffrey Blake Date: Fri, 15 Feb 2013 17:40:10 -0500 Subject: [PATCH] cpu: Avoid duplicate entries in tracking structures for writes to misc regs setMiscReg currently makes a new entry for each write to a misc reg without checking for duplicates, this can cause a triggering of the assert if an instruction get replayed and writes to the same misc regs multiple times. This fix prevents duplicate entries and instead updates the value. --- src/cpu/o3/dyn_inst.hh | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/src/cpu/o3/dyn_inst.hh b/src/cpu/o3/dyn_inst.hh index c8cdf7a1f..082c1f5d4 100644 --- a/src/cpu/o3/dyn_inst.hh +++ b/src/cpu/o3/dyn_inst.hh @@ -149,8 +149,18 @@ class BaseO3DynInst : public BaseDynInst void setMiscReg(int misc_reg, const MiscReg &val) { /** Writes to misc. registers are recorded and deferred until the - * commit stage, when updateMiscRegs() is called. + * commit stage, when updateMiscRegs() is called. First, check if + * the misc reg has been written before and update its value to be + * committed instead of making a new entry. If not, make a new + * entry and record the write. */ + for (int idx = 0; idx < _numDestMiscRegs; idx++) { + if (_destMiscRegIdx[idx] == misc_reg) { + _destMiscRegVal[idx] = val; + return; + } + } + assert(_numDestMiscRegs < TheISA::MaxMiscDestRegs); _destMiscRegIdx[_numDestMiscRegs] = misc_reg; _destMiscRegVal[_numDestMiscRegs] = val; -- 2.30.2