[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Qemu-ppc] [PATCH 7/7] target/ppc: Use non-arithmetic conversions fo

From: Richard Henderson
Subject: Re: [Qemu-ppc] [PATCH 7/7] target/ppc: Use non-arithmetic conversions for fp load/store
Date: Thu, 5 Jul 2018 09:48:17 -0700
User-agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.8.0

On 07/05/2018 09:31 AM, Programmingkid wrote:
>> On Jul 3, 2018, at 11:17 AM, Richard Henderson <address@hidden> wrote:
>> Memory operations have no side effects on fp state.
>> The use of a "real" conversions between float64 and float32
>> would raise exceptions for SNaN and out-of-range inputs.
> Would you have any documentation that tells us about converting
> between 64 bit and 32 bit floating points?

Spelled out right at the beginning of sections 4.6 (load) and 4.7 (store) of
Book 1 of the Power ISA manual (version 3.0B) [0].

I've double-checked vs RISU[1] testing of LFS and STFS, with master traces
generated on Power 8 ppc64le, so I don't see anything immediately wrong with
the patch.  But I haven't had time to look further than that.


[0] https://openpowerfoundation.org/?resource_lib=power-isa-version-3-0
[1] https://git.linaro.org/people/peter.maydell/risu.git

reply via email to

[Prev in Thread] Current Thread [Next in Thread]