Re: Simple/Fast Algorithm for binary logarithm in C (on ARM7)

Rafael Deliano schrieb:

Can anyone point to fixed-point logarithmic routines I could use
(resp. tailor to my needs)?

Good book with an idea on that :
Crenshaw "Math Toolkit for Real Time Programming" CMP Books 2000

Is it worth buying it?

I adapted it to 6502/FORTH but
http://www.embeddedforth.de Heft 9
is no longer free. But there was a preprint in
http://www.forth-ev.de/filemgmt_data/files/4d2004_1.pdf
( FORTH e.V. has now all issues of the magazine back to 1984
available
for download, http://www.forth-ev.de/filemgmt/viewcat.php?cid=2
but no good index yet ).
Both descriptions are in german.

Thanks for the link. The description sounds good, unfortunately the
listing appears somehow broken (at least it's not readable to me...).

Beyond that one would have to dig out literature on logarithmic
numbersystems. The best known published implementation for a
controller was FOCUS for the Z80 in assembler.

I think I remember that... But this time I just need a few single
logarithms within a great mass of linear arithmetics, so I think a log
numbersystem wouldn't help me much.

However, the bitlog function appears to be useful here, so I would
greatly appreciate more info on it.

Tilmann

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