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Re: FOSDEM thoughts

On Wed, Mar 05, 2008 at 05:47:43AM +0100, Roman Zippel wrote:
> Hi,
> On Tue, 4 Mar 2008, Kurt Mahan wrote:
> > With respect to Floating Point there are differences within the Coldfire
> > V4 family.  The M547x/M548x have the FPU you have been discussing.  The
> > M5445x doesn't have any FPU hardware and requires everything to be
> > compiled with softfloat.
> Linux/m68k assumes a FPU to be present, CF doesn't even know about the 
> extendend fp precision (long double), but it's currently used by m68k.


Yeah, m68k allows extended fp precision, but that doesn't mean you have
to use it. The opcodes to talk to the FPU in the other two precisions
are the same across CF and m68k, anyway; the only difference is in
FMOVEM, but that's only useful if you want to save registers on a stack,
anyway. If you just assume that it'll be taking 80 bytes per register,
even on coldfire, you'll be fine.

Of course, I might be missing something, but in that case please do
point me to it.

<Lo-lan-do> Home is where you have to wash the dishes.
  -- #debian-devel, Freenode, 2004-09-22

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