Re: [Qemu-devel] [PATCH 15/19] Add VSX xmax/xmin Instructions

[Peter Maydell]

On 25 October 2013 14:52, Tom Musta <address@hidden> wrote:
> On 10/24/2013 5:10 PM, Peter Maydell wrote:
>>
>> Can't you use the min and max softfloat functions? Those are
>> there specifically because the corner cases mean you can't
>> implement them using the comparisons. (For instance for
>> the example you quote of max(-0.0, +0.0) they return +0.0
>> as you require.)

> I tried this but didn't have much luck getting results to match
> the P7 hardware.  Unfortunately, I don't recall the details.
> Let me try this approach again.

The functions are supposed to match the IEEE mandated min/max
behaviour, and I tested the ARM instructions that use them,
so unless the PPC chip designers have gone rather off-piste
they ought to work :-) (It can happen, though, IIRC x86 has
some rather weird non-IEEE min/max insns.)

-- PMM