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Re: [PATCH 1/2] target/arm: Disable VFPv4-D32 when NEON is not available
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From: |
Peter Maydell |
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Subject: |
Re: [PATCH 1/2] target/arm: Disable VFPv4-D32 when NEON is not available |
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Date: |
Thu, 29 Sep 2022 16:29:22 +0100 |
On Thu, 29 Sept 2022 at 16:22, Richard Henderson
<richard.henderson@linaro.org> wrote:
>
> On 9/29/22 04:44, Peter Maydell wrote:
> > Architecturally, Neon implies that you must have 32 dp registers,
> > but not having Neon does not imply that you must only have 16.
> > In particular, the Cortex-A15 always implements VFPv4-D32
> > whether Neon is enabled or not.
>
> A15 requires VFP == NEON in its configuration.
No, it requires that if you have Neon then you have VFP;
but it allows all of:
* no VFP or Neon
* VFP, no Neon
* VFP and Neon
https://developer.arm.com/documentation/ddi0438/i/neon-and-vfp-unit/about-neon-and-vfp-unit
-- PMM