diff options
Diffstat (limited to 'libc/arch-mips/string/memcpy.c')
| -rw-r--r-- | libc/arch-mips/string/memcpy.c | 91 |
1 files changed, 91 insertions, 0 deletions
diff --git a/libc/arch-mips/string/memcpy.c b/libc/arch-mips/string/memcpy.c new file mode 100644 index 0000000..5551a6d --- /dev/null +++ b/libc/arch-mips/string/memcpy.c @@ -0,0 +1,91 @@ +/* $OpenBSD: memcpy.c,v 1.1 2014/11/30 19:43:56 deraadt Exp $ */ +/*- + * Copyright (c) 1990 The Regents of the University of California. + * All rights reserved. + * + * This code is derived from software contributed to Berkeley by + * Chris Torek. + * + * 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. + */ + +#include <string.h> +#include <stdlib.h> +#include <syslog.h> + +/* + * sizeof(word) MUST BE A POWER OF TWO + * SO THAT wmask BELOW IS ALL ONES + */ +typedef long word; /* "word" used for optimal copy speed */ + +#define wsize sizeof(word) +#define wmask (wsize - 1) + +/* + * Copy a block of memory, not handling overlap. + */ +void * +memcpy(void *dst0, const void *src0, size_t length) +{ + char *dst = dst0; + const char *src = src0; + size_t t; + + if (length == 0 || dst == src) /* nothing to do */ + goto done; + + /* + * Macros: loop-t-times; and loop-t-times, t>0 + */ +#define TLOOP(s) if (t) TLOOP1(s) +#define TLOOP1(s) do { s; } while (--t) + + /* + * Copy forward. + */ + t = (long)src; /* only need low bits */ + if ((t | (long)dst) & wmask) { + /* + * Try to align operands. This cannot be done + * unless the low bits match. + */ + if ((t ^ (long)dst) & wmask || length < wsize) + t = length; + else + t = wsize - (t & wmask); + length -= t; + TLOOP1(*dst++ = *src++); + } + /* + * Copy whole words, then mop up any trailing bytes. + */ + t = length / wsize; + TLOOP(*(word *)dst = *(word *)src; src += wsize; dst += wsize); + t = length & wmask; + TLOOP(*dst++ = *src++); +done: + return (dst0); +} |