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Diffstat (limited to 'lib/libutils/isoc/newlib/memcpy.c')
-rw-r--r-- | lib/libutils/isoc/newlib/memcpy.c | 134 |
1 files changed, 134 insertions, 0 deletions
diff --git a/lib/libutils/isoc/newlib/memcpy.c b/lib/libutils/isoc/newlib/memcpy.c new file mode 100644 index 0000000..8cd8d7c --- /dev/null +++ b/lib/libutils/isoc/newlib/memcpy.c @@ -0,0 +1,134 @@ +/* + * Copyright (c) 1994-2009 Red Hat, Inc. + * 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. + * + * 3. Neither the name of the copyright holder 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 COPYRIGHT HOLDERS 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 COPYRIGHT HOLDER 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. + */ + +/* +FUNCTION + <<memcpy>>---copy memory regions + +ANSI_SYNOPSIS + #include <string.h> + void* memcpy(void *<[out]>, const void *<[in]>, size_t <[n]>); + +TRAD_SYNOPSIS + #include <string.h> + void *memcpy(<[out]>, <[in]>, <[n]> + void *<[out]>; + void *<[in]>; + size_t <[n]>; + +DESCRIPTION + This function copies <[n]> bytes from the memory region + pointed to by <[in]> to the memory region pointed to by + <[out]>. + + If the regions overlap, the behavior is undefined. + +RETURNS + <<memcpy>> returns a pointer to the first byte of the <[out]> + region. + +PORTABILITY +<<memcpy>> is ANSI C. + +<<memcpy>> requires no supporting OS subroutines. + +QUICKREF + memcpy ansi pure +*/ + +#include "_ansi.h" +#include <string.h> + +/* Nonzero if either X or Y is not aligned on a "long" boundary. */ +#define UNALIGNED(X, Y) \ + (((long)X & (sizeof(long) - 1)) | ((long)Y & (sizeof(long) - 1))) + +/* How many bytes are copied each iteration of the 4X unrolled loop. */ +#define BIGBLOCKSIZE (sizeof(long) << 2) + +/* How many bytes are copied each iteration of the word copy loop. */ +#define LITTLEBLOCKSIZE (sizeof(long)) + +/* Threshhold for punting to the byte copier. */ +#define TOO_SMALL(LEN) ((LEN) < BIGBLOCKSIZE) + +_PTR +_DEFUN(memcpy, (dst0, src0, len0), _PTR dst0 _AND _CONST _PTR src0 _AND + size_t len0) +{ +#if defined(PREFER_SIZE_OVER_SPEED) || defined(__OPTIMIZE_SIZE__) + char *dst = (char *)dst0; + char *src = (char *)src0; + + _PTR save = dst0; + + while (len0--) + *dst++ = *src++; + + return save; +#else + char *dst = dst0; + _CONST char *src = src0; + long *aligned_dst; + _CONST long *aligned_src; + + /* If the size is small, or either SRC or DST is unaligned, + then punt into the byte copy loop. This should be rare. */ + if (!TOO_SMALL(len0) && !UNALIGNED(src, dst)) { + aligned_dst = (long *)dst; + aligned_src = (long *)src; + + /* Copy 4X long words at a time if possible. */ + while (len0 >= BIGBLOCKSIZE) { + *aligned_dst++ = *aligned_src++; + *aligned_dst++ = *aligned_src++; + *aligned_dst++ = *aligned_src++; + *aligned_dst++ = *aligned_src++; + len0 -= BIGBLOCKSIZE; + } + + /* Copy one long word at a time if possible. */ + while (len0 >= LITTLEBLOCKSIZE) { + *aligned_dst++ = *aligned_src++; + len0 -= LITTLEBLOCKSIZE; + } + + /* Pick up any residual with a byte copier. */ + dst = (char *)aligned_dst; + src = (char *)aligned_src; + } + + while (len0--) + *dst++ = *src++; + + return dst0; +#endif /* not PREFER_SIZE_OVER_SPEED */ +} |