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 * 3. All advertising materials mentioning features or use of this software
17 *    must display the following acknowledgement:
18 *	This product includes software developed by the University of
19 *	California, Berkeley and its contributors.
20 * 4. Neither the name of the University nor the names of its contributors
21 *    may be used to endorse or promote products derived from this software
22 *    without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 */
36
37#include "config.h"
38
39#if defined(LIBC_SCCS) && !defined(lint)
40static const char sccsid[] = "@(#)bcopy.c	8.1 (Berkeley) 6/4/93";
41#endif /* LIBC_SCCS and not lint */
42
43#include <string.h>
44
45/*
46 * sizeof(word) MUST BE A POWER OF TWO
47 * SO THAT wmask BELOW IS ALL ONES
48 */
49typedef	int word;		/* "word" used for optimal copy speed */
50
51#define	wsize	sizeof(word)
52#define	wmask	(wsize - 1)
53
54/*
55 * Copy a block of memory, handling overlap.
56 * This is the routine that actually implements
57 * (the portable versions of) bcopy, memcpy, and memmove.
58 *
59 * PUBLIC: #ifndef HAVE_MEMCPY
60 * PUBLIC: void *memcpy __P((void *, const void *, size_t));
61 * PUBLIC: #endif
62 * PUBLIC: #ifndef HAVE_MEMMOVE
63 * PUBLIC: void *memmove __P((void *, const void *, size_t));
64 * PUBLIC: #endif
65 */
66#ifdef MEMCOPY
67void *
68memcpy(dst0, src0, length)
69#else
70#ifdef MEMMOVE
71void *
72memmove(dst0, src0, length)
73#else
74void
75bcopy(src0, dst0, length)
76#endif
77#endif
78	void *dst0;
79	const void *src0;
80	register size_t length;
81{
82	register char *dst = dst0;
83	register const char *src = src0;
84	register size_t t;
85
86	if (length == 0 || dst == src)		/* nothing to do */
87		goto done;
88
89	/*
90	 * Macros: loop-t-times; and loop-t-times, t>0
91	 */
92#define	TLOOP(s) if (t) TLOOP1(s)
93#define	TLOOP1(s) do { s; } while (--t)
94
95	if ((unsigned long)dst < (unsigned long)src) {
96		/*
97		 * Copy forward.
98		 */
99		t = (int)src;	/* only need low bits */
100		if ((t | (int)dst) & wmask) {
101			/*
102			 * Try to align operands.  This cannot be done
103			 * unless the low bits match.
104			 */
105			if ((t ^ (int)dst) & wmask || length < wsize)
106				t = length;
107			else
108				t = wsize - (t & wmask);
109			length -= t;
110			TLOOP1(*dst++ = *src++);
111		}
112		/*
113		 * Copy whole words, then mop up any trailing bytes.
114		 */
115		t = length / wsize;
116		TLOOP(*(word *)dst = *(word *)src; src += wsize; dst += wsize);
117		t = length & wmask;
118		TLOOP(*dst++ = *src++);
119	} else {
120		/*
121		 * Copy backwards.  Otherwise essentially the same.
122		 * Alignment works as before, except that it takes
123		 * (t&wmask) bytes to align, not wsize-(t&wmask).
124		 */
125		src += length;
126		dst += length;
127		t = (int)src;
128		if ((t | (int)dst) & wmask) {
129			if ((t ^ (int)dst) & wmask || length <= wsize)
130				t = length;
131			else
132				t &= wmask;
133			length -= t;
134			TLOOP1(*--dst = *--src);
135		}
136		t = length / wsize;
137		TLOOP(src -= wsize; dst -= wsize; *(word *)dst = *(word *)src);
138		t = length & wmask;
139		TLOOP(*--dst = *--src);
140	}
141done:
142#if defined(MEMCOPY) || defined(MEMMOVE)
143	return (dst0);
144#else
145	return;
146#endif
147}
148