freebsd-dev/sys/libkern/memset.c
Mateusz Guzik ba96f37758 Use __builtin for various mem* and b* (e.g. bzero) routines.
Some of the routines were using artificially limited builtin already,
drop the explicit limit.

The use of builtins allows quite often allows the compiler to elide the call
or most zeroing to begin with. For instance, if the target object is 32 bytes
in size and gets zeroed + has 16 bytes initialized, the compiler can just
add code to zero out the rest.

Note not all the primites have asm variants and some of the existing ones
are not optimized. Maintaines are strongly encourage to take a look
(regardless of this change).
2018-06-02 18:03:35 +00:00

44 lines
1.6 KiB
C

/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (C) 1992-2007 The FreeBSD Project. 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 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 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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#define LIBKERN_INLINE
#include <sys/types.h>
#include <sys/libkern.h>
void *
(memset)(void *b, int c, size_t len)
{
char *bb;
for (bb = (char *)b; len--; )
*bb++ = c;
return (b);
}