Hi,

I have been looking at the problem of libsbc performance on arm. My 
first pass is on the decoder. I'm trying to cut down deeply nested fp 
multiply/divide ops.

I originally planned regression tests in the build process for 
performance/correctness but decided against them:

  - performance may actually go down on x86 where I build when we reduce 
  fp usage
  - the character of roundoff errors will change and the lossy stream 
will probably look different even when it is still "correct"

Anyway, I will need to know the range of certain values in order to make 
much progress. I tried hunting down how they are calculated but it gets 
difficult very quickly.

Can I get help with the ranges for bits[ch][sb] in sbc_unpack_frame and 
the state.* vectors if they're bounded?

How about this first little patch?

Brad