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List:       gcc
Subject:    Re: [WWWDocs] Deprecate support for non-thumb ARM devices
From:       Kyrill Tkachov <kyrylo.tkachov () foss ! arm ! com>
Date:       2016-02-29 11:37:18
Message-ID: 56D42D6E.8090108 () foss ! arm ! com
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On 28/02/16 21:34, Joel Sherrill wrote:
> 
> On February 28, 2016 3:20:24 PM CST, Gerald Pfeifer <gerald@pfeifer.com> wrote:
> > On Wed, 24 Feb 2016, Richard Earnshaw (lists) wrote:
> > > I propose to commit this patch later this week.
> > +       Support for revisions of the ARM architecture prior to ARMv4t
> > has
> > +       been deprecated and will be removed in a future GCC release.
> > +       This affects ARM6, ARM7 (but not ARM7TDMI), ARM8, StrongARM,
> > and
> > +       Faraday fa526 and fa626 devices, which do not have support for
> > +       the Thumb execution state.
> > 
> > I am wondering whether this may be confusing for those not
> > intricately familiar with the older history of ARM platforms.
> > 
> > ARMv8 is pretty new, googling for it has
> > http://www.arm.com/products/processors/armv8-architecture.php
> > as first hit, for example, and the only difference versus ARM8
> > is that little lower-case "v".
> I assume this means a number of values for the various -mXXX arguments will be \
> removed. Would it be more helpful to list those values? 
> I have to agree with Gerald. I think this will obsolete a few older RTEMS BSPs but \
> based on that wording, I don't know which.

ARM8 is a processor, whereas ARMv8-A is an architecture.
I think Richard's link earlier in the thread:

https://community.arm.com/groups/processors/blog/2011/11/02/arm-fundamentals-introduction-to-understanding-arm-processors


gives a good explanation of the naming schemes.
The -mcpu/-mtune arguments that would be deprecated can be found by looking at the
file config/arm/arm-cores.def and finding all the ARM_CORE entries that have '4' or \
lower in their 4th field These would be:
arm2,arm250,arm3,arm6,arm60,arm600,arm610,arm620,arm7,arm7d,arm7di,arm70,arm700,arm700i,arm710,
 arm720,arm710c,arm7100,arm7500,arm7500fe,arm7m,arm7dm,arm7dmi,arm8,arm810,strongarm,strongarm110,
 strongarm1100,strongarm1110,fa526,fa626.

The arguments to -march that would be deprecated are:
armv2,armv2a,armv3,armv3m,armv4.

I personally think that list is a bit too long for changes.html.
Do you think it would add more clarity for people who are not familiar with the \
situation?

Thanks,
Kyrill

> > Gerald
> --joel
> 


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