[vorbis-dev] floating point exceptions, and questions.

[Michael Smith]

I've been working on tracking down a variety of problems with the post
beta2 branch, mostly related to floating point precision issues, which
cause floating point exceptions. 

These tend to have nasty effects like making libvorbis not work on your
typical alpha (which doesn't mask them like x86 does by default).

These seem to be turning up in a number of places, mainly in psy.c - I'm
slowly dealing with each of them. 

The last one goes back to the todB() macro defined in scales.h:
#define todB(x)   ((x)==0?-9.e40:log(fabs(x))*8.6858896)

Now that we're using floats instead of doubles in most places, this -9e40
is actually -INF, causing various problems. Easy enough to fix. So, finally
getting to the question - what should this be changed to, and is there
anything else which a change here will impact? 

This is probably a question for Monty to answer, but I thought I'd throw it
out here in case anyone else has some idea, since I don't know how long
Monty will take to answer.

Michael

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