> On Feb. 4, 2017, 8:21 a.m., Jason Lowe-Power wrote:
> > Lol, that code is hard to understand. But, LGTM.
> > 
> > What are you using to test this? Any chance you can commit the test so we 
> > don't accidentally break this again in the future?

This bug was manifesting in the ROCr runtime while it is loading libraries, it 
manifested as a segfualt (unmapped addr panic) because an address calculation 
was corrupted due to this instruction. I manually tested this instruction by 
comparing its output to the result of 64b multiplication using __uint128_t. 
This is a perfect example of where instruction tests would be useful. It only 
seemed to give bad output with certain inputs, which gave the error the 
appearance of being non-deterministic.


- Tony


-----------------------------------------------------------
This is an automatically generated e-mail. To reply, visit:
http://reviews.gem5.org/r/3800/#review9400
-----------------------------------------------------------


On Feb. 3, 2017, 4:13 p.m., Tony Gutierrez wrote:
> 
> -----------------------------------------------------------
> This is an automatically generated e-mail. To reply, visit:
> http://reviews.gem5.org/r/3800/
> -----------------------------------------------------------
> 
> (Updated Feb. 3, 2017, 4:13 p.m.)
> 
> 
> Review request for Default.
> 
> 
> Repository: gem5
> 
> 
> Description
> -------
> 
> Changeset 11778:c76b78110490
> ---------------------------
> x86: fix Mul1u instruction
> 
> the Mul1uFlags and Mul1u instructions perform
> the 64b multiplication using only 64b registers, however the
> method used causes the high 64b to be corrupted for certain
> inputs. here we fix the computation.
> 
> 
> Diffs
> -----
> 
>   src/arch/x86/isa/microops/regop.isa 
> ed89cb178ecd7586296d2a2e83595174474db554 
> 
> Diff: http://reviews.gem5.org/r/3800/diff/
> 
> 
> Testing
> -------
> 
> 
> Thanks,
> 
> Tony Gutierrez
> 
>

_______________________________________________
gem5-dev mailing list
gem5-dev@gem5.org
http://m5sim.org/mailman/listinfo/gem5-dev

Reply via email to