58e97e521c
Add the `LIBC_PREVENT_STRING_KERNEL` and `LIBC_PREVENT_STRING_USER` that are meant to be selected by the chip if no libc implementation is going to be built. If selected, neither NuttX's software version of the libc nor any architecture-specific implementation will be built in the kernel or in the userspace, respectively. In this case, the linker may provide a ROM-defined version of the libc functions instead.
61 lines
1.9 KiB
C
61 lines
1.9 KiB
C
/****************************************************************************
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* libs/libc/string/lib_memcmp.c
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <sys/types.h>
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#include <string.h>
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#include "libc.h"
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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#if !defined(CONFIG_LIBC_ARCH_MEMCMP) && defined(LIBC_BUILD_STRING)
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#undef memcmp /* See mm/README.txt */
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no_builtin("memcmp")
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int memcmp(FAR const void *s1, FAR const void *s2, size_t n)
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{
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unsigned char *p1 = (unsigned char *)s1;
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unsigned char *p2 = (unsigned char *)s2;
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while (n-- > 0)
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{
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if (*p1 < *p2)
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{
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return -1;
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}
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else if (*p1 > *p2)
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{
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return 1;
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}
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p1++;
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p2++;
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}
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return 0;
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}
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#endif
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