Hello, Jim,

> >   I don't think you can turn it on from a user program...  (What do
> > you mean by "WinCE's lack of security"?  It is at least memory
> > protected, separated supervisor/user mode OS.  The reference manual of
> > XScale lists the sample code to change the cache behaviors and memory
> > region attribute flags or such, but as far as I understand (with a
> > little experiment), The instruction cannot be executed from a
> > user-level program.
> >
> 
> WinCE has little if any real security....  If it had any, it would be
> more difficult for us to replace the bootloader that comes with WinCE
> with the one that we use for Linux (we overwrite the boot sector in flash....

  Well, I'm not big fan of WinCE either, but this sounds a bit unfair.
Once it boots up, it does have the separated supervisor mode and
indeed that prevents us from changing cache behavior from user
program.  It is like saying unix is insecure because you can hit
Ctrl-C during the boot sequence and get the root privilege:-)

> >   As for the Squeak performance, there is another twist in this story.
> > The VM on SL-C700 (a PXA 250 device) feels much faster than other PXA
> > 250 based WinCEs (Aaron has reported similar with his machines...)
> > There might be some performance glitch in the VM support code.  The
> > toolchain that Sharp provide is based on 2.95.2 and I don't think it
> > does XScale specific optimization.  If we change the compiler, it may
> > get some boost.
> 
> Yes, you want a more recent toolchain to get the best performance out
> of XScale; the calling sequence, for example, really wants to be different
> to get good performance out of it.
>
> We have such toolchains available.

  This is great news.  I'll look into this once after I've got C750,
heh heh.  (Who is "we"?)

> You certainly want the proper toolchain for the PXA.  Phil Blundell or
> Jamey Hicks would be the person to ask about exactly what toolchain
> to use to build for it using GCC.

  Thank you for the reference.  I even haven't follow the
handhelds.org discussions, which I will need...

-- Yoshiki