summaryrefslogtreecommitdiff
path: root/librols/movebytes.c
blob: 3724c99ceac9ce8e730e968207b83453f9a9ab60 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
/*
 * This file has been modified for the cdrkit suite.
 *
 * The behaviour and appearence of the program code below can differ to a major
 * extent from the version distributed by the original author(s).
 *
 * For details, see Changelog file distributed with the cdrkit package. If you
 * received this file from another source then ask the distributing person for
 * a log of modifications.
 *
 */

/* @(#)movebytes.c	1.13 03/06/15 Copyright 1985, 1989, 1995-2003 J. Schilling */
/*
 *	move data
 *
 *	Copyright (c) 1985, 1989, 1995-2003 J. Schilling
 */
/*
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2
 * as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; see the file COPYING.  If not, write to the Free Software
 * Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

#include <standard.h>
#include <align.h>
#include <schily.h>

#define	DO8(a)	a; a; a; a; a; a; a; a;

EXPORT char *
movebytes(fromv, tov, cnt)
	const void	*fromv;
	void		*tov;
	int		cnt;
{
	register const char	*from	= fromv;
	register char		*to	= tov;
	register int		n;

	/*
	 * If we change cnt to be unsigned, check for == instead of <=
	 */
	if ((n = cnt) <= 0)
		return (to);

	if (from >= to) {
		/*
		 * source is on higher adresses than destination:
		 *	move bytes forwards
		 */
		if (n >= (int)(8 * sizeof (long))) {
			if (l2aligned(from, to)) {
				register const long *froml = (const long *)from;
				register long *tol = (long *)to;
				register int rem = n % (8 * sizeof (long));

				n /= (8 * sizeof (long));
				do {
					DO8 (*tol++ = *froml++);
				} while (--n > 0);

				from = (const char *)froml;
				to = (char *)tol;
				n = rem;
			}

			if (n >= 8) {
				n -= 8;
				do {
					DO8 (*to++ = *from++);
				} while ((n -= 8) >= 0);
				n += 8;
			}

			if (n > 0) do {
				*to++ = *from++;
			} while (--n > 0);
			return (to);
		}
		if (n > 0) do {
			*to++ = *from++;
		} while (--n > 0);
		return (to);
	} else {
		char *ep;

		/*
		 * source is on lower adresses than destination:
		 *	move bytes backwards
		 */
		to += n;
		from += n;
		ep = to;
		if (n >= (int)(8 * sizeof (long))) {
			if (l2aligned(from, to)) {
				register const long *froml = (const long *)from;
				register long *tol = (long *)to;
				register int rem = n % (8 * sizeof (long));

				n /= (8 * sizeof (long));
				do {
					DO8 (*--tol = *--froml);
				} while (--n > 0);

				from = (const char *)froml;
				to = (char *)tol;
				n = rem;
			}
			if (n >= 8) {
				n -= 8;
				do {
					DO8 (*--to = *--from);
				} while ((n -= 8) >= 0);
				n += 8;
			}
			if (n > 0) do {
				*--to = *--from;
			} while (--n > 0);
			return (ep);
		}
		if (n > 0) do {
			*--to = *--from;
		} while (--n > 0);
		return (ep);
	}
}