[tex-k] mf segfaults if compiled with -g3 (bug in mfmpi386.asm)

Olaf Weber olaf at infovore.xs4all.nl
Fri May 12 16:19:33 CEST 2006

Karl Berry writes:

> Hi Ed,
>     Hope I'm sending this to the right address 

> Yes.

>     and that this makes sense.

> It sounds right to me.  (Olaf?)

> I'm not sure we really need that assembly code at all, these days.  I
> wonder if compiler output would be better ...

It is clear we don't exactly _need_ the code, but it _is_ subtantially
better than the compiler-generated code, because the default
implementation is complicated by being restricted to 32 bit arithmetic
and the other alternative uses floating point.

A proper alternative is to check for 64-bit 'long' or 'long long' and
do the calculation in that type if available, falling back on the
floating-point in other cases.  But some benchmarking is necessary to
see what difference this makes, and in which direction: the code with
64bit integer arithmetic might be more compact yet lose on those
platforms where fp is substantially faster than integer arithmetic.

Olaf Weber

               (This space left blank for technical reasons.)

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