Re: [avr-gcc-list] Cicrular Buffer routines

[Bob Paddock]

On Tuesday 16 August 2005 03:40 pm, Dave Hylands wrote:

> > but size of compiled code.  The best I have done is using powers of two
> > with masks on the indexes (32 byte buffer being a convenient size).
>
> I have one that's just in a .h file. It also works for powers of 2,

You can test to make sure that you do have a power of two buffer size with the 
following:

#define myQ_SIZE    64

#define myQ_MASK ( myQ__SIZE - 1 )
#if ( myQ__SIZE & myQ__MASK )
 #error myQ_SIZE buffer size is not a power of 2
#endif

The effect is to check if only one, and only one, bit is set in myQ_SIZE.




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