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Re: [Qemu-ppc] [Qemu-devel] [PATCH 15/19] Add VSX xmax/xmin Instructions
From: |
Peter Maydell |
Subject: |
Re: [Qemu-ppc] [Qemu-devel] [PATCH 15/19] Add VSX xmax/xmin Instructions |
Date: |
Thu, 24 Oct 2013 23:10:27 +0100 |
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
- Re: [Qemu-ppc] [Qemu-devel] [PATCH 12/19] Add VSX ISA2.06 xtsqrt Instructions, (continued)
- [Qemu-ppc] [PATCH 13/19] Add VSX ISA2.06 Multiply Add Instructions, Tom Musta, 2013/10/24
- [Qemu-ppc] [PATCH 14/19] Add VSX xscmp*dp Instructions, Tom Musta, 2013/10/24
- [Qemu-ppc] [PATCH 15/19] Add VSX xmax/xmin Instructions, Tom Musta, 2013/10/24
- [Qemu-ppc] [PATCH 16/19] Add VSX Vector Compare Instructions, Tom Musta, 2013/10/24
- [Qemu-ppc] [PATCH 17/19] Add VSX Floating Point to Floating Point Conversion Instructions, Tom Musta, 2013/10/24
- [Qemu-ppc] [PATCH 18/19] Add VSX ISA2.06 Integer Conversion Instructions, Tom Musta, 2013/10/24
- [Qemu-ppc] [PATCH 19/19] Add VSX Rounding Instructions, Tom Musta, 2013/10/24