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Re: [PATCH v2] ARM: Add Cortex-A15 optimized NEON and VFP memcpy routines, with IFUNC.
- From: Will Newton <will dot newton at linaro dot org>
- To: "Carlos O'Donell" <carlos at redhat dot com>
- Cc: libc-ports at sourceware dot org, Patch Tracking <patches at linaro dot org>
- Date: Thu, 18 Apr 2013 09:01:34 +0100
- Subject: Re: [PATCH v2] ARM: Add Cortex-A15 optimized NEON and VFP memcpy routines, with IFUNC.
- References: <516D18F0 dot 4060009 at linaro dot org> <516EE108 dot 2030501 at redhat dot com>
On 17 April 2013 18:51, Carlos O'Donell <carlos@redhat.com> wrote:
> On 04/16/2013 02:25 AM, Will Newton wrote:
>> +size_t
>> +__libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
>> + size_t max)
>> +{
>> + size_t i = 0;
>> + int hwcap;
>> +
>> + hwcap = GLRO(dl_hwcap);
>> +
>> + IFUNC_IMPL (i, name, memcpy,
>> + IFUNC_IMPL_ADD (array, i, memcpy, hwcap & HWCAP_ARM_NEON,
>> + __memcpy_neon)
>> + IFUNC_IMPL_ADD (array, i, memcpy, hwcap & HWCAP_ARM_VFPv3,
>> + __memcpy_vfp)
>> + IFUNC_IMPL_ADD (array, i, memcpy, 1, __memcpy_arm));
>> +
>> + return i;
>> +}
>
> If unaligned access is a requirement why not check for it here?
>
> While unaligned access is virtually free on ARMv6 or higher it
> is still possible for the U-bit to be disabled and for this to
> crash on such systems.
Does glibc support building for this type of system? The compiler will
emit unaligned accesses by default on armv6 and above.
Also there isn't a HWCAP bit for unaligned as far as I can tell.
--
Will Newton
Toolchain Working Group, Linaro