[fio.git] / lib / ffz.h

#ifndef FIO_FFZ_H
#define FIO_FFZ_H

#include <inttypes.h>

static inline int ffs64(uint64_t word)
{
	int r = 0;

	if ((word & 0xffffffff) == 0) {
		r += 32;
		word >>= 32;
	}
	if (!(word & 0xffff)) {
		word >>= 16;
		r += 16;
	}
	if (!(word & 0xff)) {
		word >>= 8;
		r += 8;
	}
	if (!(word & 0xf)) {
		word >>= 4;
		r += 4;
	}
	if (!(word & 3)) {
		word >>= 2;
		r += 2;
	}
	if (!(word & 1)) {
		word >>= 1;
		r += 1;
	}

	return r;
}

#ifndef ARCH_HAVE_FFZ

static inline int ffz(unsigned long bitmask)
{
	return ffs64(~bitmask);
}

#else
#define ffz(bitmask)	arch_ffz(bitmask)
#endif

static inline int ffz64(uint64_t bitmask)
{
	return ffs64(~bitmask);
}

#endif
Commit	Line	Data
	1	#ifndef FIO_FFZ_H
	2	#define FIO_FFZ_H
	3
	4	#include <inttypes.h>
	5
	6	static inline int ffs64(uint64_t word)
	7	{
	8	int r = 0;
	9
	10	if ((word & 0xffffffff) == 0) {
	11	r += 32;
	12	word >>= 32;
	13	}
	14	if (!(word & 0xffff)) {
	15	word >>= 16;
	16	r += 16;
	17	}
	18	if (!(word & 0xff)) {
	19	word >>= 8;
	20	r += 8;
	21	}
	22	if (!(word & 0xf)) {
	23	word >>= 4;
	24	r += 4;
	25	}
	26	if (!(word & 3)) {
	27	word >>= 2;
	28	r += 2;
	29	}
	30	if (!(word & 1)) {
	31	word >>= 1;
	32	r += 1;
	33	}
	34
	35	return r;
	36	}
	37
	38	#ifndef ARCH_HAVE_FFZ
	39
	40	static inline int ffz(unsigned long bitmask)
	41	{
	42	return ffs64(~bitmask);
	43	}
	44
	45	#else
	46	#define ffz(bitmask) arch_ffz(bitmask)
	47	#endif
	48
	49	static inline int ffz64(uint64_t bitmask)
	50	{
	51	return ffs64(~bitmask);
	52	}
	53
	54	#endif