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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: |
Fri, 25 Oct 2013 14:55:38 +0100 |
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
- Re: [Qemu-ppc] [Qemu-devel] [PATCH 13/19] Add VSX ISA2.06 Multiply Add Instructions, (continued)
[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
Re: [Qemu-ppc] [Qemu-devel] [PATCH 15/19] Add VSX xmax/xmin Instructions, Peter Maydell, 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