1/*-
2 * Copyright (c) 1990 The Regents of the University of California.
3 * 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#if defined(LIBC_SCCS) && !defined(lint)
34#if 0
35static char *sccsid = "from: @(#)bcopy.c      5.11 (Berkeley) 6/21/91";
36#endif
37#if 0
38static char *rcsid = "$NetBSD: bcopy.c,v 1.2 1997/04/16 22:09:41 thorpej Exp $";
39#endif
40#endif /* LIBC_SCCS and not lint */
41#include <sys/cdefs.h>
42__FBSDID("$FreeBSD$");
43
44#include <sys/param.h>
45#ifdef _KERNEL
46#include <sys/systm.h>
47#else
48#include <string.h>
49#endif
50
51/*
52 * sizeof(word) MUST BE A POWER OF TWO
53 * SO THAT wmask BELOW IS ALL ONES
54 */
55typedef	long	word;		/* "word" used for optimal copy speed */
56
57#define	wsize	sizeof(word)
58#define wmask	(wsize - 1)
59
60/*
61 * Copy a block of memory, handling overlap.
62 * This is the routine that actually implements
63 * (the portable versions of) bcopy, memcpy, and memmove.
64 */
65void *
66memcpy(void *dst0, const void *src0, size_t length)
67{
68	char		*dst;
69	const char	*src;
70	size_t		t;
71
72	dst = dst0;
73	src = src0;
74
75	if (length == 0 || dst == src) {	/* nothing to do */
76		goto done;
77	}
78
79	/*
80	 * Macros: loop-t-times; and loop-t-times, t>0
81	 */
82#define	TLOOP(s) if (t) TLOOP1(s)
83#define	TLOOP1(s) do { s; } while (--t)
84
85	if ((unsigned long)dst < (unsigned long)src) {
86		/*
87		 * Copy forward.
88		 */
89		t = (size_t)src;	/* only need low bits */
90
91		if ((t | (uintptr_t)dst) & wmask) {
92			/*
93			 * Try to align operands.  This cannot be done
94			 * unless the low bits match.
95			 */
96			if ((t ^ (uintptr_t)dst) & wmask || length < wsize) {
97				t = length;
98			} else {
99				t = wsize - (t & wmask);
100			}
101
102			length -= t;
103			TLOOP1(*dst++ = *src++);
104		}
105		/*
106		 * Copy whole words, then mop up any trailing bytes.
107		 */
108		t = length / wsize;
109		TLOOP(*(word *)dst = *(const word *)src; src += wsize;
110		    dst += wsize);
111		t = length & wmask;
112		TLOOP(*dst++ = *src++);
113	} else {
114		/*
115		 * Copy backwards.  Otherwise essentially the same.
116		 * Alignment works as before, except that it takes
117		 * (t&wmask) bytes to align, not wsize-(t&wmask).
118		 */
119		src += length;
120		dst += length;
121		t = (uintptr_t)src;
122
123		if ((t | (uintptr_t)dst) & wmask) {
124			if ((t ^ (uintptr_t)dst) & wmask || length <= wsize) {
125				t = length;
126			} else {
127				t &= wmask;
128			}
129
130			length -= t;
131			TLOOP1(*--dst = *--src);
132		}
133		t = length / wsize;
134		TLOOP(src -= wsize; dst -= wsize;
135		    *(word *)dst = *(const word *)src);
136		t = length & wmask;
137		TLOOP(*--dst = *--src);
138	}
139done:
140	return (dst0);
141}
142
143void
144bcopy(const void *src0, void *dst0, size_t length)
145{
146
147	memcpy(dst0, src0, length);
148}
149
150