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Re: [PATCH] Use correct ARM architecture profile for optimized ARMv6t2/v7 memchr version.
- From: Richard Earnshaw <rearnsha at arm dot com>
- To: Pavel Pisa <ppisa4lists at pikron dot com>
- Cc: "newlib at sourceware dot org" <newlib at sourceware dot org>, "nickc at redhat dot com" <nickc at redhat dot com>, Sebastian Huber <sebastian dot huber at embedded-brains dot de>
- Date: Mon, 07 Jul 2014 09:36:56 +0100
- Subject: Re: [PATCH] Use correct ARM architecture profile for optimized ARMv6t2/v7 memchr version.
- Authentication-results: sourceware.org; auth=none
- References: <201407030216 dot 43438 dot ppisa4lists at pikron dot com> <53B549E1 dot 1020207 at redhat dot com> <53B55151 dot 1050104 at arm dot com> <201407061730 dot 35574 dot ppisa4lists at pikron dot com>
On 06/07/14 16:30, Pavel Pisa wrote:
> This prevents next error at link time for Cortex-R multilib option
>
> Conflicting architecture profiles A/R
> .../arm-rtems4.11/bin/ld: failed to merge target
>
> Simple ".arch armv6t2" defines null profile and can be used
> probably for all targets but chosen solution is consistent
> with attributes of other libc library objects.
>
> Other option is to eliminate ".arch" line altogether.
>
No, please don't do it this way. It will give the surprising result for
ARMv8-a (or later) of going backwards to v6t2.
You only need object file attributes to be compatible with your existing
code. armv6t2 will be enough for that; so why are you trying to
overcomplicate this?
R.
> --
>
> diff --git a/newlib/ChangeLog b/newlib/ChangeLog
> index 9f4b568..deee044 100644
> --- a/newlib/ChangeLog
> +++ b/newlib/ChangeLog
> @@ -1,3 +1,8 @@
> +2014-07-06 Pavel Pisa <pisa@cmp.felk.cvut.cz>
> +
> + * libc/machine/arm/memchr.S: Use correct ARM architecture profile
> + for ARMv6t2/v7 memchr version.
> +
> 2014-07-04 Bin Cheng <bin.cheng@arm.com>
>
> * README (--enable-newlib-nano-formatted-io): Describe.
> diff --git a/newlib/libc/machine/arm/memchr.S b/newlib/libc/machine/arm/memchr.S
> index 56bfef0..842ebf1 100644
> --- a/newlib/libc/machine/arm/memchr.S
> +++ b/newlib/libc/machine/arm/memchr.S
> @@ -46,7 +46,13 @@
> @ tidy
>
> .syntax unified
> +#if defined(__ARM_ARCH_7R__)
> + .arch armv7-r
> +#elif defined(__ARM_ARCH_7A__)
> .arch armv7-a
> +#else
> + .arch armv6t2
> +#endif
>
> #include "arm_asm.h"
>
>