How to optimize newlib for a specific ARM processor?

[Fernando Ramos]

I got it working!

Thanks to Shaun Jackman for your input. Unfortunately I have to report
that using --with-cpu option to configure does not do what is supposed
to. I saw the --with-cpu being passed from one configure level to the
next, but no change in the final outcome. What's more what I wanted to
do (optimize the xscale toolchain to use a arm922t processor) was
explicitly prohibited by gcc's configure even though it is a valid
platform to work with, as the 922t allows interworking same as the
xscale.

What worked for me was to do a regular configure and then pass the
values I wanted to the make file:

configure xxxx  xxx xxx
make all FLAGS_FOR_TARGET="-mcpu=arm922t"

The same trick works for both gcc and newlib.

FWIW, I used Suse Linux 10.1 to create the toolchain.

Fernando Ramos
Senior Software Engineer
Hypercom Corp.

-----Original Message-----
From: newlib-owner@sourceware.org [mailto:newlib-owner@sourceware.org]
On Behalf Of Fernando Ramos
Sent: Friday, September 15, 2006 4:21 PM
To: newlib@sourceware.org
Subject: How to optimize newlib for a specific ARM processor?

 
Hi, all.

I'm trying to generate newlib for a board that uses a arm922t processor.
How can I have configure (or the makefile it generates) create an
optimized version of newlib for that processor?
I see that there's a whole set of optimizations for xscale, but I think
it is not necessary to go to that extreme of customization of the
configuration files.
Can I specify the target as arm922t-elf and hope that the libraries will
be compiled with "-mcpu=arm922t"?
Should I simply use something like CFLAGS="-mcpu=arm922t" when invoking
make ?

Suggestions are welcome...

Fernando Ramos
Senior Software Engineer
Hypercom Corp.