mirror of
https://github.com/apache/nuttx.git
synced 2026-08-20 04:58:28 +00:00
bd6b226546
Most hardware accesses the memory through a 64-bit bus, so handle the data in 64-bit chunks instead of "long" chunks which are only 32-bit wide on the 32-bit platforms. * Add the libc_data_t type (unsigned long long) and move the shared UNALIGNED/UNALIGNED_X/ALIGNED, LITTLEBLOCKSIZE, TOO_SMALL and DETECTNULL helpers from the individual C files to libs/libc/libc.h. * Convert all lib_bsd*.c implementations to the new type and macros, which also drops the duplicated LONG_MAX conditionals. Assisted-by: Claude:claude-opus-5 Signed-off-by: anjiahao <anjiahao@xiaomi.com>
94 lines
2.8 KiB
C
94 lines
2.8 KiB
C
/****************************************************************************
|
|
* libs/libc/string/lib_bsdmemcmp.c
|
|
*
|
|
* SPDX-License-Identifier: BSD
|
|
* SPDX-FileCopyrightText: 1994-2009 Red Hat, Inc. All rights reserved
|
|
*
|
|
* Copyright (c) 1994-2009 Red Hat, Inc. All rights reserved.
|
|
*
|
|
* This copyrighted material is made available to anyone wishing to use,
|
|
* modify, copy, or redistribute it subject to the terms and conditions
|
|
* of the BSD License. This program is distributed in the hope that
|
|
* it will be useful, but WITHOUT ANY WARRANTY expressed or implied,
|
|
* including the implied warranties of MERCHANTABILITY or FITNESS FOR
|
|
* A PARTICULAR PURPOSE. A copy of this license is available at
|
|
* http://www.opensource.org/licenses. Any Red Hat trademarks that are
|
|
* incorporated in the source code or documentation are not subject to
|
|
* the BSD License and may only be used or replicated with the express
|
|
* permission of Red Hat, Inc.
|
|
*
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Included Files
|
|
****************************************************************************/
|
|
|
|
#include <nuttx/config.h>
|
|
#include <sys/types.h>
|
|
#include <string.h>
|
|
|
|
#include "libc.h"
|
|
|
|
/****************************************************************************
|
|
* Pre-processor Definitions
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Public Functions
|
|
****************************************************************************/
|
|
|
|
#if !defined(CONFIG_LIBC_ARCH_MEMCMP) && defined(LIBC_BUILD_MEMCMP)
|
|
#undef memcmp
|
|
no_builtin("memcmp")
|
|
int memcmp(FAR const void *s1, FAR const void *s2, size_t n)
|
|
{
|
|
FAR unsigned char *p1 = (FAR unsigned char *)s1;
|
|
FAR unsigned char *p2 = (FAR unsigned char *)s2;
|
|
FAR libc_data_t *a1;
|
|
FAR libc_data_t *a2;
|
|
|
|
/* If the size is too small, or either pointer is unaligned,
|
|
* then we punt to the byte compare loop. Hopefully this will
|
|
* not turn up in inner loops.
|
|
*/
|
|
|
|
if (!TOO_SMALL(n) && !UNALIGNED(p1, p2))
|
|
{
|
|
/* Otherwise, load and compare the blocks of memory one
|
|
* word at a time.
|
|
*/
|
|
|
|
a1 = (FAR libc_data_t *)p1;
|
|
a2 = (FAR libc_data_t *)p2;
|
|
while (n >= LITTLEBLOCKSIZE)
|
|
{
|
|
if (*a1 != *a2)
|
|
{
|
|
break;
|
|
}
|
|
|
|
a1++;
|
|
a2++;
|
|
n -= LITTLEBLOCKSIZE;
|
|
}
|
|
|
|
/* check s mod LBLOCKSIZE remaining characters */
|
|
|
|
p1 = (FAR unsigned char *)a1;
|
|
p2 = (FAR unsigned char *)a2;
|
|
}
|
|
|
|
while (n--)
|
|
{
|
|
if (*p1 != *p2)
|
|
{
|
|
return *p1 - *p2;
|
|
}
|
|
|
|
p1++;
|
|
p2++;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
#endif
|