1/*-
2 * Copyright (c) 1990, 1993
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley by
6 * Chris Torek.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 * 4. Neither the name of the University nor the names of its contributors
17 *    may be used to endorse or promote products derived from this software
18 *    without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 */
32
33#include "string.h"
34
35/*
36 * sizeof(word) MUST BE A POWER OF TWO
37 * SO THAT wmask BELOW IS ALL ONES
38 */
39typedef	int word;		/* "word" used for optimal copy speed */
40
41#define	wsize	sizeof(word)
42#define	wmask	(wsize - 1)
43
44/*
45 * Copy a block of memory, handling overlap.
46 * This is the routine that actually implements
47 * (the portable versions of) bcopy, memcpy, and memmove.
48 */
49
50__attribute__((visibility("hidden")))
51void * memcpy(void *dst0, const void *src0, size_t length)
52{
53	char *dst = dst0;
54	const char *src = src0;
55	size_t t;
56
57	if (length == 0 || dst == src)		/* nothing to do */
58		goto done;
59
60	/*
61	 * Macros: loop-t-times; and loop-t-times, t>0
62	 */
63#define	TLOOP(s) if (t) TLOOP1(s)
64#define	TLOOP1(s) do { s; } while (--t)
65
66	if ((unsigned long)dst < (unsigned long)src) {
67		/*
68		 * Copy forward.
69		 */
70		t = (uintptr_t)src;	/* only need low bits */
71		if ((t | (uintptr_t)dst) & wmask) {
72			/*
73			 * Try to align operands.  This cannot be done
74			 * unless the low bits match.
75			 */
76			if ((t ^ (uintptr_t)dst) & wmask || length < wsize)
77				t = length;
78			else
79				t = wsize - (t & wmask);
80			length -= t;
81			TLOOP1(*dst++ = *src++);
82		}
83		/*
84		 * Copy whole words, then mop up any trailing bytes.
85		 */
86		t = length / wsize;
87		TLOOP(*(word *)dst = *(word *)src; src += wsize; dst += wsize);
88		t = length & wmask;
89		TLOOP(*dst++ = *src++);
90	} else {
91		/*
92		 * Copy backwards.  Otherwise essentially the same.
93		 * Alignment works as before, except that it takes
94		 * (t&wmask) bytes to align, not wsize-(t&wmask).
95		 */
96		src += length;
97		dst += length;
98		t = (uintptr_t)src;
99		if ((t | (uintptr_t)dst) & wmask) {
100			if ((t ^ (uintptr_t)dst) & wmask || length <= wsize)
101				t = length;
102			else
103				t &= wmask;
104			length -= t;
105			TLOOP1(*--dst = *--src);
106		}
107		t = length / wsize;
108		TLOOP(src -= wsize; dst -= wsize; *(word *)dst = *(word *)src);
109		t = length & wmask;
110		TLOOP(*--dst = *--src);
111	}
112done:
113	return (dst0);
114}
115
116__attribute__((visibility("hidden")))
117void *
118memmove(void *s1, const void *s2, size_t n)
119{
120	return memcpy(s1, s2, n);
121}
122
123__attribute__((visibility("hidden")))
124void
125bcopy(const void *s1, void *s2, size_t n)
126{
127	memcpy(s2, s1, n);
128}
129