Re: [Qemu-devel] [PATCH 12/14] VSX Stage 4: Add Scalar SP Fused Multiply-Adds

[Tom Musta]

On 11/13/2013 5:14 PM, Richard Henderson wrote:
> On 11/14/2013 06:49 AM, Tom Musta wrote:
>> I have also done quite a bit of random and targeted random testing using 
>> Power
>> hardware to produce expected results.  The targeted random tests followed 
>> your
>> suggestion above: generate AxB + C where abs(exp(A) - exp(B)) = 23 and
>> abs(exp(A) - exp(C)) = 46.  Several million test patterns have been generated
>> and played back through QEMU without any miscompares in the numerical 
>> results.
> 
> Here's an example that produces wrong results when rounding to double first.
> Replace the portable math.h calls with ppc asm as necessary.
> 
> <snip>
> r~
> 

Thanks, Richard.  You have convinced me.