xscale-elf-gcc and arm-elf-gcc

[Richard Earnshaw]

> 
> > xscale-elf-gcc code seems to be more compact than arm-elf-gcc. What
> > enables this?
> 
> Presumably the use of the extra, XScale instructions.  Do you have a
> specific example in mind ?

No, most of the differences are due to the fact that XScale uses the ARM 
architecture 5te (armv5te) instruction set, whereas the arm-elf-gcc 
configuration will default to using the armv3 instruction set (as 
implemented on the arm6).

You can enable most of the optimizations on the arm-elf-gcc configuration 
by adding the command line option -march=armv4 when you compile your 
source code.

A final note: most of the so-called XScale instructions that gcc adds with 
-mcpu=xscale are nothing more than standard armv5te instructions; I will 
be installing a fix sometime to correct this anomaly.

R.