sys: Extract __bitcount* from sys/types.h to new sys/bitcount.h

This will allow the code to be reused by the cross-build sys/types.h
wrapper in order to provide the APIs for greater compatibility. This
also provides a path towards eventually removing the definitions from
sys/types.h altogether if so desired by gradually migrating users to
including sys/bitcount.h explicitly, but that is not the primary goal
here.

Note that the copyright header is a direct copu of sys/types.h's given
that's where this code comes from. This could be replaced in future with
a more specific one restricted to just the code in question, depending
on what the copyright for that code is.

Reviewed by:	emaste
Differential Revision:	https://reviews.freebsd.org/D36132
This commit is contained in:
Jessica Clarke 2022-08-18 02:46:27 +01:00
parent b0ce7dfc5e
commit 92fc50b496
2 changed files with 108 additions and 62 deletions

107
sys/sys/bitcount.h Normal file
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@ -0,0 +1,107 @@
/*-
* SPDX-License-Identifier: BSD-3-Clause
*
* Copyright (c) 1982, 1986, 1991, 1993, 1994
* The Regents of the University of California. All rights reserved.
* (c) UNIX System Laboratories, Inc.
* All or some portions of this file are derived from material licensed
* to the University of California by American Telephone and Telegraph
* Co. or Unix System Laboratories, Inc. and are reproduced herein with
* the permission of UNIX System Laboratories, Inc.
*
* 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.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
*
* @(#)types.h 8.6 (Berkeley) 2/19/95
* $FreeBSD$
*/
#ifndef _SYS_BITCOUNT_H_
#define _SYS_BITCOUNT_H_
#include <sys/_types.h>
#ifdef __POPCNT__
#define __bitcount64(x) __builtin_popcountll((__uint64_t)(x))
#define __bitcount32(x) __builtin_popcount((__uint32_t)(x))
#define __bitcount16(x) __builtin_popcount((__uint16_t)(x))
#define __bitcountl(x) __builtin_popcountl((unsigned long)(x))
#define __bitcount(x) __builtin_popcount((unsigned int)(x))
#else
/*
* Population count algorithm using SWAR approach
* - "SIMD Within A Register".
*/
static __inline __uint16_t
__bitcount16(__uint16_t _x)
{
_x = (_x & 0x5555) + ((_x & 0xaaaa) >> 1);
_x = (_x & 0x3333) + ((_x & 0xcccc) >> 2);
_x = (_x + (_x >> 4)) & 0x0f0f;
_x = (_x + (_x >> 8)) & 0x00ff;
return (_x);
}
static __inline __uint32_t
__bitcount32(__uint32_t _x)
{
_x = (_x & 0x55555555) + ((_x & 0xaaaaaaaa) >> 1);
_x = (_x & 0x33333333) + ((_x & 0xcccccccc) >> 2);
_x = (_x + (_x >> 4)) & 0x0f0f0f0f;
_x = (_x + (_x >> 8));
_x = (_x + (_x >> 16)) & 0x000000ff;
return (_x);
}
#ifdef __LP64__
static __inline __uint64_t
__bitcount64(__uint64_t _x)
{
_x = (_x & 0x5555555555555555) + ((_x & 0xaaaaaaaaaaaaaaaa) >> 1);
_x = (_x & 0x3333333333333333) + ((_x & 0xcccccccccccccccc) >> 2);
_x = (_x + (_x >> 4)) & 0x0f0f0f0f0f0f0f0f;
_x = (_x + (_x >> 8));
_x = (_x + (_x >> 16));
_x = (_x + (_x >> 32)) & 0x000000ff;
return (_x);
}
#define __bitcountl(x) __bitcount64((unsigned long)(x))
#else
static __inline __uint64_t
__bitcount64(__uint64_t _x)
{
return (__bitcount32(_x >> 32) + __bitcount32(_x));
}
#define __bitcountl(x) __bitcount32((unsigned long)(x))
#endif
#define __bitcount(x) __bitcount32((unsigned int)(x))
#endif
#endif /* !_SYS_BITCOUNT_H_ */

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@ -310,68 +310,7 @@ typedef _Bool bool;
* The following are all things that really shouldn't exist in this header,
* since its purpose is to provide typedefs, not miscellaneous doodads.
*/
#ifdef __POPCNT__
#define __bitcount64(x) __builtin_popcountll((__uint64_t)(x))
#define __bitcount32(x) __builtin_popcount((__uint32_t)(x))
#define __bitcount16(x) __builtin_popcount((__uint16_t)(x))
#define __bitcountl(x) __builtin_popcountl((unsigned long)(x))
#define __bitcount(x) __builtin_popcount((unsigned int)(x))
#else
/*
* Population count algorithm using SWAR approach
* - "SIMD Within A Register".
*/
static __inline __uint16_t
__bitcount16(__uint16_t _x)
{
_x = (_x & 0x5555) + ((_x & 0xaaaa) >> 1);
_x = (_x & 0x3333) + ((_x & 0xcccc) >> 2);
_x = (_x + (_x >> 4)) & 0x0f0f;
_x = (_x + (_x >> 8)) & 0x00ff;
return (_x);
}
static __inline __uint32_t
__bitcount32(__uint32_t _x)
{
_x = (_x & 0x55555555) + ((_x & 0xaaaaaaaa) >> 1);
_x = (_x & 0x33333333) + ((_x & 0xcccccccc) >> 2);
_x = (_x + (_x >> 4)) & 0x0f0f0f0f;
_x = (_x + (_x >> 8));
_x = (_x + (_x >> 16)) & 0x000000ff;
return (_x);
}
#ifdef __LP64__
static __inline __uint64_t
__bitcount64(__uint64_t _x)
{
_x = (_x & 0x5555555555555555) + ((_x & 0xaaaaaaaaaaaaaaaa) >> 1);
_x = (_x & 0x3333333333333333) + ((_x & 0xcccccccccccccccc) >> 2);
_x = (_x + (_x >> 4)) & 0x0f0f0f0f0f0f0f0f;
_x = (_x + (_x >> 8));
_x = (_x + (_x >> 16));
_x = (_x + (_x >> 32)) & 0x000000ff;
return (_x);
}
#define __bitcountl(x) __bitcount64((unsigned long)(x))
#else
static __inline __uint64_t
__bitcount64(__uint64_t _x)
{
return (__bitcount32(_x >> 32) + __bitcount32(_x));
}
#define __bitcountl(x) __bitcount32((unsigned long)(x))
#endif
#define __bitcount(x) __bitcount32((unsigned int)(x))
#endif
#include <sys/bitcount.h>
#if __BSD_VISIBLE