[vorbis-dev] optimization patches

[Firelight Multimedia]

2 if statements is not faster than 1 fabs and 1 if statement.   A floating
point compare is very slow, and is subject to branch mispredictions.   fabs
is a 1 cycle operation (it just clears the sign bit in the fpu), and only
incurs one floating point compare.

>>
>> > envelope.c
>> > if (fabs(...) < min) creates horrible assembler (gcc 2.95, x86),
>> > so changed to if (... < min && ... > -min). muchos faster.
>>
>> Intersting. I'll keep it in mind.
>
>I added -mno-ieee-fp to the compile flags; I _think_ fabs() is ok in
>this case. I'll test; no ieee is a huge speedup on x86 anyway.

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