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Re: Raspberry pi support

From: Vladimir 'φ-coder/phcoder' Serbinenko
Subject: Re: Raspberry pi support
Date: Mon, 08 Apr 2013 21:58:12 +0200
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> Then I need to add a configure test for this, causing a failure if the

> option is missing. A toolchain that does not support this option cannot
> be used to build a reliable bare-metal image for ARM.
> FSF GCC 4.7 onwards (and some distribution-patched 4.6) support this flag.

Why? According to;a=commitdiff;h=eb04cafba3a6f1eddbdb5ec031d8a7074930d5b9
older version simply have "implicit" -mno-unaligned-access and we
support only GCC.

>>> And for reasons stated above, -march= should be set to whatever your
>>> target architecture is. Extracted by configure, I suppose?
>> Hence --target-cpu=armv[67] proposal.g
> I think it is a bit overkill, since CFLAGS can cover it.

The difference is that for all other targets you can compile for the
lowest supported CPU and use it for all devices with this target but if
I understand correctly on armv7 you need to insert some opcodes which
would cause a crash on armv6. Is only cache flushing displays such kind
of backward incompatibility?
Another question:
I see that efi/startup.S transitions to thumb but not uboot/startup.S.
Was uboot compiled as arm in your port as well or do I miss sth?

> /
>     Leif

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