Re: update ARM platform HALs

[John Dallaway <john at dallaway dot org dot uk>]

Jifl

Jonathan Larmour wrote:

> John Dallaway wrote:
>
>> Jonathan Larmour wrote:
>>
>>> John Dallaway wrote:
>>>
>>>> The eCosCentric arm-eabi pre-built toolchains do not include StrongARM
>>>> multi-libs. AFAIK, users who want to build eCos for these targets will
>>>> therefore need to either build their own arm-eabi-gcc or revert to
>>>> CYGBLD_GLOBAL_COMMAND_PREFIX == "arm-elf" and use the older arm-elf-gcc
>>>> 3.2.1. Can you please let me know what the intention is here so I can
>>>> mention this in the eCos 3.0 release notes?
>>>
>>> This was discussed before IRL, and I believe until I hear to the
>>> contrary that strongarm should probably still work. It just won't be
>>> perfectly optimal as it will fall back to the arm7tdmi multilib (the
>>> default); but now actually looking at GCC sources, I think it may have
>>> only a virtually perceptible effect even then.
>>
>> IIRC, Bart observed a SIGTRAP in libgcc (udivsi3?) when running up eCos
>> built with arm-eabi-gcc 4.3.2 on the ipaq target. So perhaps users would
>> be better off sticking with arm-elf-gcc 3.2.1 for StrongARM? I'm not
>> proposing that we spend any further time investigating the problem, just
>> seeking clarification as to what we should recommend to users.
> 
> Well, I've had a closer look, and indeed the prebuilt tools won't just
> work after all, because, even if thumb interworking is disabled, gcc
> uses ARMv4t insns like 'bx', which aren't available on strongarm's ARMv4.
> 
> If people want to use strongarm, they can indeed either use the older
> tools, or rebuild the current tools with strongarm multilibs added.

OK. Thanks for the clarification.

> Of course, I don't expect anyone to be using strongarm in new designs as
> they've been discontinued.

Yes, I appreciate that this is unlikely to affect many users. The set of
multi-libs in the pre-built arm-eabi tools seems perfectly reasonable
for eCos in 2009.

John Dallaway