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File: [Development] / linux-2.6-xfs / include / asm-generic / bitops / fls.h (download)

Revision 1.1, Mon May 29 16:35:25 2006 UTC (11 years, 5 months ago) by nathans.longdrop.melbourne.sgi.com
Branch: MAIN
CVS Tags: HEAD

Merge up to 2.6.17-rc5.
Merge of 2.6.x-xfs-melb:linux:26065a by kenmcd.

#ifndef _ASM_GENERIC_BITOPS_FLS_H_
#define _ASM_GENERIC_BITOPS_FLS_H_

/**
 * fls - find last (most-significant) bit set
 * @x: the word to search
 *
 * This is defined the same way as ffs.
 * Note fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32.
 */

static inline int fls(int x)
{
	int r = 32;

	if (!x)
		return 0;
	if (!(x & 0xffff0000u)) {
		x <<= 16;
		r -= 16;
	}
	if (!(x & 0xff000000u)) {
		x <<= 8;
		r -= 8;
	}
	if (!(x & 0xf0000000u)) {
		x <<= 4;
		r -= 4;
	}
	if (!(x & 0xc0000000u)) {
		x <<= 2;
		r -= 2;
	}
	if (!(x & 0x80000000u)) {
		x <<= 1;
		r -= 1;
	}
	return r;
}

#endif /* _ASM_GENERIC_BITOPS_FLS_H_ */