Re: ldrb vs ldrh in gcc-3.4.4 (ARM)

[Richard Earnshaw <rearnsha at gcc dot gnu dot org>]

On Thu, 2005-08-18 at 09:07, Steven Scholz wrote:
> Steven Scholz wrote:
> 
> > Richard,
> > 
> >>> Thanks a million. Maybe you could explain the difference of arm920t 
> >>> and arm9tdmi as well, please?
> >>
> >>
> >>
> >> The arm9tdmi is the main 'core' of the CPU.  The arm920t is the core
> >> plus the associated cache, mmu, and system registers.   Different models
> >> all have substantially the same 'core' but may have different (or
> >> missing) additional parts...
> > 
> > 
> > Thanks. So when I am using Freescale i.MX and Atmel AT91RM9200 which are 
> > both arm920t I rather use
> > 
> >     GCC_EXTRA_CONFIG="--with-float=soft --with-cpu=arm920t \
> >                           --enable-cxx-flags=-mcpu=arm920t"
> > 
> > instead of
> > 
> >     GCC_EXTRA_CONFIG="--with-float=soft --with-cpu=arm9tdmi \
> >                           --enable-cxx-flags=-mcpu=arm9tdmi"
> > 
> > when building the toolchain. Right?
> 
> ARGH! There's no "--with-cpu=arm920t" !
> 
This has been fixed in gcc-4.0 and it's also been fixed in the
CodeSourcery version of 3.4
(http://www.codesourcery.com/gnu_toolchains/arm/).

> gcc/config/arm/arm.h only knows
> 
> #define TARGET_CPU_arm9         0x0080
> #define TARGET_CPU_arm9tdmi     0x0080
> 
> So when arm9tdmi is only thre core without caches will "--with-cpu=arm9tdmi" use 
> the caches in a sane way ?

It probably makes no difference in 3.4 and earlier.  It might have a
small effect in later versions, but gcc doesn't really understand caches
and their layout yet.

------
Want more information?  See the CrossGCC FAQ, http://www.objsw.com/CrossGCC/
Want to unsubscribe? Send a note to crossgcc-unsubscribe@sources.redhat.com