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RE: coldfire math when using gcc


Hi,

>> After some benchmarking I came to the conclusion that the
>hardware divide is
>> not being used. Is there any compiler option to turn this on?
>>
>
>If this is the egcs-1.1.something release then it I suspect it will not
>support the hardware divide or mac instructions.

This is the case. The egcs compiler that comes with uCLinux can quite
happily be swapped with something newer like gcc-2.95.2. You still need to
keep egcs-1.1 around to compiler the kernel unless it has been fixed. Modify
user/arch/coldfire/build.mk.

>Wayne Deeter, David Fiddes and others have been working on the support.
>You can find info about it on :

I have a patch that tidies the assembler options and fixes a few bugs in
binutils. Linus Nordberg submitted MAC and hw divide support for the
ColdFire which will be in binutils-2.10 (due any day now). Peter Jakubek
[pjak@snafu.de] has a patch against gcc-2.95.2 that adds hwdivide support
which gives a significant speedup to integer maths.

The collection of patches can be had from
http://fiddes.net/coldfire/download/gcc-m68k-patches-r7-20000413.tar.gz

Wayne Deeter [wrd@logical-co.com] wrote a siginifcantly improved version of
the gcc floating point library for the ColdFire. It requires quite a bit of
work to get it into shape for submission for gcc. This speeds up things like
double multiplies by a factor of two or so. It does not use or require mac
or hw divide instructions.

>I do not know the status of these patches or if anyone has attempted to
>get them into the gcc and binutils sources.

I have submitted my patches to binutils but I'm dragging my feet on getting
the copyright assignment form in... it will happen.

Dave


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