I agree with Istvan about this.

Regards,
Mike

-----Original Message-----
>From: Istvan Varga 
>Sent: Jan 23, 2006 3:42 PM
>To: csound-devel@lists.sourceforge.net
>Subject: Re: [Cs-dev] function tables power-of-2, etc
>
>On Monday 23 January 2006 20:20, Matt Ingalls wrote:
>
>> is that really true?  when i looked into this [ about 5 years ago! ]
>> all i found was some bit-wise operations on index increments for
>> oscillators and stuff -- it would be no big deal to replace the bit-wise
>> stuff with a modulo or  if statement?
>
>Simply replacing a & with a % is not enough, as the latter cannot
>deal with negative numbers correctly, so you need an additional
>if statement to fix that. Also, a % is much slower than a &.
>An if statement is again not enough, as you need at least two to
>wrap negative numbers, and more to deal with the possibility of
>a very large index.
>In any case, using the & operator is the simplest and fastest
>way to wrap any integer value to a 0..N-1 range, as long as
>N is an integer power of two.
>Additionally, more changes are needed to clean up any tricky code
>that assumes in some (often non-obvious) way a power of two or at
>least even table size. There are many possibilities for introducing
>bugs, something that is best avoided when a release is just about
>to be made.
>
>
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