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/*-
* Copyright (c) 2001 Jake Burkholder <jake@FreeBSD.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
#ifndef _MACHINE_RUNQ_H_
#define _MACHINE_RUNQ_H_
#define RQB_LEN (1UL) /* Number of priority status words. */
#define RQB_L2BPW (6UL) /* Log2(sizeof(rqb_word_t) * NBBY)). */
#define RQB_BPW (1UL<<RQB_L2BPW) /* Bits in an rqb_word_t. */
#define RQB_BIT(pri) (1UL << ((pri) & (RQB_BPW - 1)))
#define RQB_WORD(pri) ((pri) >> RQB_L2BPW)
#define RQB_FFS(word) (__ffsl(word) - 1)
/*
* Type of run queue status word.
*/
typedef u_int64_t rqb_word_t;
static __inline u_int64_t
__popcnt(u_int64_t bits)
{
u_int64_t result;
__asm __volatile("popcnt %0=%1" : "=r" (result) : "r" (bits));
return result;
}
static __inline int
__ffsl(u_long mask)
{
if (__predict_false(mask == 0ul))
return (0);
return (__popcnt(mask ^ (mask - 1)));
}
#endif
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