updated Cortex-M3 build script (again)

[Yann E. MORIN]

Michael,
All,

On Tuesday 03 March 2009 23:20:40 Michael Abbott wrote:
> On Tue, 3 Mar 2009, Yann E. MORIN wrote:
> > Cortex-M3 is a Thumb-only processor (if I'm not mistaken).
> Thumb only?  You astonish me.

http://www.arm.com/products/CPUs/families/CortexFamily.html
Well... It can do Thumb-2 as well... ;-)

> I'm pretty sure, for a start, that you  
> can't do any interrupt handling in thumb processing -- I mean, the 
> alternate registers are not accessible in this mode, if I'm not mistaken.

Oh, don't get me wrong: I don't know either!
In fact, Thumb-2 is a 32-bit variant of (extension to) Thumb, and
it is possible to do IRQ handling in Thumb-2.

> Well, I'm quite wrong: just downloaded the "ARM v7-M Architecture 
> Application Level Reference Manual" and it says "ARMv7-M only executes 
> Thumb instructions".  How intruiging.

And Thumb-2 insns. ;-)

> By the way, thoroughly off topic -- anybody know how to identify, from sh 
> script only, whether you're running on an old ABI glibc or new EABI 
> install?  `uname` is clearly useless (it's nothing to do with the kernel), 
> and digging about in /lib hasn't been very instructive yet -- the output 
> of /lib/libc.so.6 although intriuging isn't terribly useful for this task. 
> My fallback is going to have to be to run a sample program, I guess...

http://wiki.debian.org/ArmEabiPort says:

----8<---
    * objdump -x for compiled binary: 
private flags = 4000002: [Version4 EABI] [has entry point]

    * "file" on compiled binary (under Debian): 
ELF 32-bit LSB executable, ARM, version 1 (SYSV), for GNU/Linux 2.4.17, dynamically linked (uses shared libs), for GNU/Linux 2.4.17, stripped

    * "readelf -h | grep Flags"" 
Flags: 0x4000002, has entry point, Version4 EABI
----8<---

Hope that helps.

Regards,
Yann E. MORIN.

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