>Depends how approximately you are willing to tolerate.  Since you are
>in the audio industry (?) perhaps +/- 1 or 2 dB is OK?  If so, then
>compute log (to base 2) by finding the bit number of the most significant
>'1' bit, then use a lookup table on the most significant 4 bits to add
>a bit more precision, and finally do a fixed point multiply to convert
>into log base 10.

Would it help if I said it could be from ~0 to 1?  I was just thinking about
the results and I wouldn't mind scaling the input to within 0 to 1/2 even.

Could you please explain the most significant 4-bits thing to me.  I
understand the most significant bit thing.  I'm actually doing this with a
DSP attached to a PIC, so floating point stuff is OK by me.

Stuart Allman
Studio Sound Design
studio@halcyon.com