Integer math lib in XC??

[Interactive_Matter]

Hi,

I am looking for some fast imlementations for basic integer math in XC. Like abs(), min() or max(). Is there any library shipping with XC/XDE that I have not noticed?
math.h and fastmath.h are disabled in XC - and they deal with floating point. But there should be somewhere some basic routines that are better than my if/else non sense.

Thanks

Marcus

[daveg]

I am looking for some fast imlementations for basic integer math in XC. Like abs(), min() or max(). Is there any library shipping with XC/XDE that I have not noticed?

`labs' in the C library will do abs for integers, and you can just include stdlib.h in your XC program to get this to work.

min and max are usually done as macros (with the irritating side-effect of evaluating the arguments twice) or as an inline function. I don't believe that there are standard library functions for these (but I could well be wrong..)

[Interactive_Matter]

Thanks,

understood the abs thing. The min/max macros puzzle me a bit but I can work with it ;)

Marcus

[Andy]

Here's a fairly small abs function I've used. Don't know how it compares to the library version.

Code: Select all

// Absolute of signed integer
static __inline int FASTABS(int x) 
{
	int sign;

	sign = x >> (sizeof(int) * 8 - 1);
	x ^= sign;
	x -= sign;

	return x;
}

[Interactive_Matter]

Any recomendation for a good resource for those kinds of algorithms (must admint I am more familiar with Java - there you do not think about this very often ;) )

[richard]

Any recomendation for a good resource for those kinds of algorithms (must admint I am more familiar with Java - there you do not think about this very often ;) )

The following page is a good source for various tricks:

http://graphics.stanford.edu/~seander/bithacks.html

I'd also highly recommend Hacker's Delight.