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Re: [RFC PATCH 00/29] arm64: Scalable Vector Extension core support
- From: Dave Martin <Dave dot Martin at arm dot com>
- To: Florian Weimer <fweimer at redhat dot com>
- Cc: libc-alpha at sourceware dot org, Ard Biesheuvel <ard dot biesheuvel at linaro dot org>, Marc Zyngier <Marc dot Zyngier at arm dot com>, gdb at sourceware dot org, Yao Qi <qiyaoltc at gmail dot com>, Christoffer Dall <christoffer dot dall at linaro dot org>, Alan Hayward <alan dot hayward at arm dot com>, Torvald Riegel <triegel at redhat dot com>, linux-arm-kernel at lists dot infradead dot org
- Date: Thu, 1 Dec 2016 12:19:21 +0000
- Subject: Re: [RFC PATCH 00/29] arm64: Scalable Vector Extension core support
- Authentication-results: sourceware.org; auth=none
- References: <20161130120654.GJ1574@e103592.cambridge.arm.com> <3e8afc5a-1ba9-6369-462b-4f5a707d8b8a@redhat.com> <20161130135631.GK1574@e103592.cambridge.arm.com> <dbcd545f-1358-6a80-5a9f-3e4a3c93189a@redhat.com> <20161201103048.GO1574@e103592.cambridge.arm.com>
On Thu, Dec 01, 2016 at 10:30:51AM +0000, Dave Martin wrote:
[...]
> Basically, all the *new* state is caller-save.
>
> The Neon/FPSIMD regs V8-V15 are callee-save, so in the SVE view
> Zn[bits 127:0] is callee-save for all n = 8..15.
Ramana is right -- the current procedure call standard (ARM IHI 0055B)
only requires the bottom _64_ bits of V8-V15 to be preserved (not all
128 bits as I stated).
[...]
Cheers
---Dave