freebsd-skq/sys/i386/include/runq.h
peter 4830c34648 Move the "- 1" into the RQB_FFS(mask) macro itself so that
implementations can provide a base zero ffs function if they wish.
This changes
  #define RQB_FFS(mask) (ffs64(mask))
  foo = RQB_FFS(mask) - 1;
to
  #define RQB_FFS(mask) (ffs64(mask) - 1)
  foo = RQB_FFS(mask);
On some platforms we can get the "- 1" for free, eg: those that use the
C code for ffs64().

Reviewed by:	jake (in principle)
2002-06-20 06:21:20 +00:00

47 lines
1.8 KiB
C

/*
* 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 (2) /* Number of priority status words. */
#define RQB_L2BPW (5) /* Log2(sizeof(rqb_word_t) * NBBY)). */
#define RQB_BPW (1<<RQB_L2BPW) /* Bits in an rqb_word_t. */
#define RQB_BIT(pri) (1 << ((pri) & (RQB_BPW - 1)))
#define RQB_WORD(pri) ((pri) >> RQB_L2BPW)
#define RQB_FFS(word) (ffs(word) - 1)
/*
* Type of run queue status word.
*/
typedef u_int32_t rqb_word_t;
#endif