Dear Dirk,
In message <[EMAIL PROTECTED]> you wrote:
...
> Now, the remaining question is what to do with
>
> +CROSS_COMPILE = arm-none-linux-gnueabi-
>
> +PLATFORM_CPPFLAGS += -march=armv7a
>
> we still have above.
>
> Checking our code, it seems we need -march=armv7a. Else one file
> wouldn't compile any more. E.g. replacing armv7a with armv4 results in
>
> - a lot of warnings "warning: target CPU does not support interworking"
>
> - start.S compilation in our patch fails:
>
> start.S: Assembler messages:
> start.S:466: Error: selected processor does not support `isb'
> start.S:475: Error: selected processor does not support `clz r5,r4'
> start.S:500: Error: selected processor does not support `isb'
Is it really necessary to use these instructions, or would it be
possible to modify the code to use other (less optimal, but generally
available) instructions?
> Possible solutions:
>
> a) Post patch without modifying CROSS_COMPILE, resulting in usage of
> arm-linux-. With this, we would locally overwrite CROSS_COMPILE at
> command line with toolchain we like. I'm not sure if the standard
> arm-linux- toolchain used for "make all" supports -march=armv7a, though.
Assume it doesn't. I think U-Boot code should make as little
requirements on the toolchain as possible. Of course there emay be
situations where it cannot be avoided - but if all we win is a
certain level of better optimization in the code, I tend to decide in
favour of less restrictive build environments.
> b) Introduce something like new
>
> ifeq ($(ARCH),cortex-arm)
> CROSS_COMPILE = arm-none-linux-gnueabi-
> endif
>
> I don't know if this would be accepted and how to do it cleanly, though.
This is just another way to express the same problem.
> c) More?
Try to modify the code such that any of the many ARM tool chains
floating around can build your code.
Best regards,
Wolfgang Denk
--
DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: [EMAIL PROTECTED]
I'm frequently appalled by the low regard you Earthmen have for life.
-- Spock, "The Galileo Seven", stardate 2822.3
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