> On 2011-06-08 22:52:15, Gabe Black wrote:
> > I think you missed some (maybe just one) version of PC state defined in the 
> > ISAs themselves. ARM may be the only one, but you should double check to be 
> > sure. Also, for all these you could define them using ==, something like 
> > return !(*this == opc);
> 
> Korey Sewell wrote:
>     The "!(*this == opc)" is interesting. If you do it that way, it's 
> definitely more programmable for the long term since one change to the equals 
> operator definition will propagate. But, is that way adding two extra 
> operations there? 1 to dereference the this pointer and then another to do 
> the NOT operation? The "==" operator is the more used operator but if for 
> some reason the "!=" operator become popular within gem5 wouldnt it be 
> slightly slower?

I think defining != in terms of == is much preferred for the reasons you said.  
The compiler should inline the == definition into != where appropriate, so the 
performance difference for optimized code should be somewhere between 
non-existent and negligible, and certainly worthwhile given how much simpler 
and more robust the code will be.  You should just be able to define it once on 
the base class too which will simplify things even more.


- Steve


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On 2011-06-08 22:46:05, Korey Sewell wrote:
> 
> -----------------------------------------------------------
> This is an automatically generated e-mail. To reply, visit:
> http://reviews.m5sim.org/r/738/
> -----------------------------------------------------------
> 
> (Updated 2011-06-08 22:46:05)
> 
> 
> Review request for Default, Ali Saidi, Gabe Black, Steve Reinhardt, and 
> Nathan Binkert.
> 
> 
> Summary
> -------
> 
> cpus/isa: add a != operator for pcstate
> 
> 
> Diffs
> -----
> 
>   src/arch/generic/types.hh 77d12d8f7971 
> 
> Diff: http://reviews.m5sim.org/r/738/diff
> 
> 
> Testing
> -------
> 
> 
> Thanks,
> 
> Korey
> 
>

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