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 * 3. 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 * From: sys/powerpc/powerpc/bcopy.c
33 */
34
35#include <sys/cdefs.h>
36__FBSDID("$FreeBSD$");
37
38#include <sys/param.h>
39#include <sys/systm.h>
40
41/*
42 * sizeof(word) MUST BE A POWER OF TWO
43 * SO THAT wmask BELOW IS ALL ONES
44 */
45typedef	long	word;		/* "word" used for optimal copy speed */
46
47#define	wsize	sizeof(word)
48#define wmask	(wsize - 1)
49
50/*
51 * Copy a block of memory, handling overlap.
52 * This is the routine that actually implements
53 * (the portable versions of) bcopy, memcpy, and memmove.
54 */
55void *
56memcpy(void *dst0, const void *src0, size_t length)
57{
58	char		*dst;
59	const char	*src;
60	size_t		t;
61
62	dst = dst0;
63	src = src0;
64
65	if (length == 0 || dst == src) {	/* nothing to do */
66		goto done;
67	}
68
69	/*
70	 * Macros: loop-t-times; and loop-t-times, t>0
71	 */
72#define	TLOOP(s) if (t) TLOOP1(s)
73#define	TLOOP1(s) do { s; } while (--t)
74
75	if ((unsigned long)dst < (unsigned long)src) {
76		/*
77		 * Copy forward.
78		 */
79		t = (size_t)src;	/* only need low bits */
80
81		if ((t | (uintptr_t)dst) & wmask) {
82			/*
83			 * Try to align operands.  This cannot be done
84			 * unless the low bits match.
85			 */
86			if ((t ^ (uintptr_t)dst) & wmask || length < wsize) {
87				t = length;
88			} else {
89				t = wsize - (t & wmask);
90			}
91
92			length -= t;
93			TLOOP1(*dst++ = *src++);
94		}
95		/*
96		 * Copy whole words, then mop up any trailing bytes.
97		 */
98		t = length / wsize;
99		TLOOP(*(word *)dst = *(const word *)src; src += wsize;
100		    dst += wsize);
101		t = length & wmask;
102		TLOOP(*dst++ = *src++);
103	} else {
104		/*
105		 * Copy backwards.  Otherwise essentially the same.
106		 * Alignment works as before, except that it takes
107		 * (t&wmask) bytes to align, not wsize-(t&wmask).
108		 */
109		src += length;
110		dst += length;
111		t = (uintptr_t)src;
112
113		if ((t | (uintptr_t)dst) & wmask) {
114			if ((t ^ (uintptr_t)dst) & wmask || length <= wsize) {
115				t = length;
116			} else {
117				t &= wmask;
118			}
119
120			length -= t;
121			TLOOP1(*--dst = *--src);
122		}
123		t = length / wsize;
124		TLOOP(src -= wsize; dst -= wsize;
125		    *(word *)dst = *(const word *)src);
126		t = length & wmask;
127		TLOOP(*--dst = *--src);
128	}
129done:
130	return (dst0);
131}
132
133void
134bcopy(const void *src0, void *dst0, size_t length)
135{
136
137	memcpy(dst0, src0, length);
138}
139
140