> On 2010-11-10 08:07:39, Steve Reinhardt wrote:
> > So it looks like whether you call setMiscReg() or setMiscRegNoEffect() then 
> > you buffer the update and call setMiscReg() later... i.e., even if you 
> > called setMiscRegNoEffect() originally you end up calling setMiscReg() at 
> > commit.
> > 
> > Are there ever cases where we call setMiscRegNoEffect() from an 
> > instruction?  I thought it was strictly for things like system 
> > initialization and restoring from checkpoints anyway... maybe we don't need 
> > it in the ExecContext interface.
> > 
> > Also, I see that these predate your change, but why do we need both the 
> > setMiscReg() calls and the setMiscRegOperand() calls?  Is one of them 
> > deprecated?  Can we take this opportunity to update the comments to 
> > distinguish them?  We shouldn't have two different functions for which the 
> > descriptive comment is completely identical IMO.
> >
> 
> Ali Saidi wrote:
>     You're right... The only place i can find an xc using 
> setMiscRegNoEffect() is locked_mem.hh for alpha and what is the exact copy of 
> it for MIPS. It seems like that could be setMiscReg(). The implementation for 
> LOCKED_ADDR is identical (there are no effects). Perhaps we should remove it 
> from the xc. My guess was that it was used with the intention of making it 
> cheaper by not having the cpu squash when it happens, but in reality that 
> didn't work out. 
>     
>     The difference between the operand and no operand version is that the 
> operand version gets the dest misc register from the instruction while the 
> non-operand one expects it passed in as a parameter. One should be 
> implemented in terms of the other, but both seem to be used.

Yeah, I think generally setMiscRegOperand is going to be called from generated 
code and setMiscReg is going to be used by handwritten code where the index is 
provided directly.


- Gabe


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This is an automatically generated e-mail. To reply, visit:
http://reviews.m5sim.org/r/298/#review473
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On 2010-11-08 15:46:52, Ali Saidi wrote:
> 
> -----------------------------------------------------------
> This is an automatically generated e-mail. To reply, visit:
> http://reviews.m5sim.org/r/298/
> -----------------------------------------------------------
> 
> (Updated 2010-11-08 15:46:52)
> 
> 
> Review request for Default.
> 
> 
> Summary
> -------
> 
> O3: Make all instructions that write a misc register not perform the write 
> until commit.
> 
> ARM Instructions updating cumulative flags (ARM FP exceptions and saturation
> flags) are not serialized.
> 
> Added aliases for ARM FP exceptions and saturation flags in FPSCR.
> 
> 
> Diffs
> -----
> 
>   src/arch/arm/isa.cc f61e079ad05e 
>   src/arch/arm/isa/insts/fp.isa f61e079ad05e 
>   src/arch/arm/isa/insts/neon.isa f61e079ad05e 
>   src/arch/arm/isa/operands.isa f61e079ad05e 
>   src/arch/arm/miscregs.hh f61e079ad05e 
>   src/cpu/o3/commit_impl.hh f61e079ad05e 
>   src/cpu/o3/dyn_inst.hh f61e079ad05e 
>   src/cpu/o3/dyn_inst_impl.hh f61e079ad05e 
> 
> Diff: http://reviews.m5sim.org/r/298/diff
> 
> 
> Testing
> -------
> 
> 
> Thanks,
> 
> Ali
> 
>

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