Yea, that's why I'm saying just delete that old code for EAcomp and MemAcc because of all the CPU models use initiateAcc and completeAcc anyway...
On Tue, Mar 17, 2009 at 12:53 PM, Gabe Black <gbl...@eecs.umich.edu> wrote: > Korey Sewell wrote: > > I theorize it hasn't come up, because the code isn't used to stress > > that case. > > > > On line 1668 of isa_parser.py, you'll see this: > > if op_desc.is_src: > > op_desc.src_reg_idx = self.numSrcRegs > > self.numSrcRegs += 1 > > > > So basically, registers are read in order > > > > The picture is this for a STQ instruction for alpha: > > EA = Rb + disp > > Mem = Ra > > > > Normally, Ra is evaluated and assigned an operand before Rb > > (operands.isa) so when this code gets executed in initiateAcc(), so > > isa_parser.py:1668 contributes to this: > > Ra = readIntRegOperand(this, 0) > > Rb = readIntRegOperand(this, 1) > > > > Everything works fine. > > > > However, when you have the eaComp() split instruction then you only > > the ea-code snippet being generated: > > EA = Rb + disp > > > > So isa_parser.py:1668 processes the registers operands and assigns Rb > > to operand 0 since it's the only operand in the code snippet. Hence: > > Rb = readIntRegOperand(this, 0) > > > > Now, that you've read Rb with the wrong operand, bad stuff is going to > > happen which first and foremost results in bad TLB translation. > I haven't looked at the code, but I'm betting these are generated with > different InstObjParams which don't know about all the code snippets at > once. A rule we added (and never wrote down as far as I know) is that > you should use one InstObjParam with all the different pieces of code > and then substitute it wherever it's needed. That was to fix a similar > issue I was having with the SPARC split memory stuff. > > Gabe > _______________________________________________ > m5-dev mailing list > m5-dev@m5sim.org > http://m5sim.org/mailman/listinfo/m5-dev > -- ---------- Korey L Sewell Graduate Student - PhD Candidate Computer Science & Engineering University of Michigan
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