Ian Dall <Ian.Dall@dsto.defence.gov.au> writes:

[ My comment about not knowing quite where to find info about the
  __asm__ syntax and options deleted... ]

> Well, I assume you have read the gcc info documentation. If not, look
> under "C Extensions" and "Extended Asm". I find it is not too bad, although
> you need to follow the constraints cross reference to find out what all
> the letters mean.

OK, I admit that I haven't looked too recently.  I was searching
everywhere for anything back when I was trying to add the quad int
operations, and didn't find much.  Even in the "Porting GCC"
document.  There were some comments about some of it, and it seemed
that everything I tried from that, Matthias told me was hitting
known bugs in GCC.

That was 2.5.x though as I remember, and it was bad enough that I
pretty much gave up and tried the method of "clone code, tweak it,
work around the bugs that are left".  The best advice I found in
the docs was something to the effect of "Find another machine
description that is close to the processor you'll be working with
and modify that as necessary."  Pretty poor advice for someone who
has not ever looked at the innards of big compilers before, but
that's about all I found.

Has it changed enough to make it worth my while to dig through all
the docs all over again?  I hope so...

Jon