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

[Peter Maydell]

On 24 October 2013 17:26, Tom Musta <address@hidden> wrote:
> This patch adds the VSX floating point maximum and minimum
> instructions:
>
>   - xsmaxdp, xvmaxdp, xvmaxsp
>   - xsmindp, xvmindp, xvminsp
>
> Because of the Power ISA definitions of maximum and minimum
> on various boundary cases, the standard softfloat comparison
> routines (e.g. float64_lt) do not work as well as one might
> think.  Therefore specific routines for comparing 64 and 32
> bit floating point numbers are implemented in the PowerPC
> helper code.

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.)

thanks
-- PMM