RFA: ARM unwinding tutorial

[Nick Clifton]

Hi Mark,

> This patch adds some tutorial to the GAS manual explaining how to use
> some of the ARM unwinding pseudo ops from hand-written assembly code.
> The intent is to enable users who need to write assembly code that
> calls functions which might throw exceptions.  Paul Brook has reviewed
> the documentation for accuracy.
> 
> OK to apply?

Approved - please apply.

Note, since Paul is an ARM maintainer for the binutils he could also 
have approved this patch.

> + @verbatim
> + void callee(int *);
> + 
> + int caller() {
> +   int i;
> +   callee(&i);
> +   return i; 
> + }
> + @end verbatim

Just a suggestion - I like to follow the GNU Coding conventions in 
example pieces of code in the documentation.  It makes everything 
consistent.

Cheers
   Nick