[sdiy] help understanding circular buffers for delay line

[Matthew Smith]

Quoth Andrew Simper at 02/03/12 14:37...
> If you are using a power of 2 buffer length then just use an "&" of
> the length - 1 for starters as this will be much easier to code, worry
> about optimisation later:
>
> buffer [index&  (length - 1)]
>
> so for a fixed integer sample delay you would have:
>
> inpos = (inpos + 1)&  (length - 1);
> buffer [inpos] = input;
> output = buffer [(inpos - delay)&  ( length - 1)];
>
> and make sure delay is less than length - 1

Cool, thanks for that little optimisation.

Logical operation should mean that the process will take a more 
predictable time to execute, unlike using conditionals.

-- 
Matthew Smith

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