xref: /OK3568_Linux_fs/kernel/arch/nios2/lib/memmove.c (revision 4882a59341e53eb6f0b4789bf948001014eff981)
1*4882a593Smuzhiyun /*
2*4882a593Smuzhiyun  * Copyright (C) 2011 Tobias Klauser <tklauser@distanz.ch>
3*4882a593Smuzhiyun  * Copyright (C) 2004 Microtronix Datacom Ltd
4*4882a593Smuzhiyun  *
5*4882a593Smuzhiyun  * This file is subject to the terms and conditions of the GNU General Public
6*4882a593Smuzhiyun  * License.  See the file "COPYING" in the main directory of this archive
7*4882a593Smuzhiyun  * for more details.
8*4882a593Smuzhiyun  */
9*4882a593Smuzhiyun 
10*4882a593Smuzhiyun #include <linux/types.h>
11*4882a593Smuzhiyun #include <linux/string.h>
12*4882a593Smuzhiyun 
memmove(void * d,const void * s,size_t count)13*4882a593Smuzhiyun void *memmove(void *d, const void *s, size_t count)
14*4882a593Smuzhiyun {
15*4882a593Smuzhiyun 	unsigned long dst, src;
16*4882a593Smuzhiyun 
17*4882a593Smuzhiyun 	if (!count)
18*4882a593Smuzhiyun 		return d;
19*4882a593Smuzhiyun 
20*4882a593Smuzhiyun 	if (d < s) {
21*4882a593Smuzhiyun 		dst = (unsigned long) d;
22*4882a593Smuzhiyun 		src = (unsigned long) s;
23*4882a593Smuzhiyun 
24*4882a593Smuzhiyun 		if ((count < 8) || ((dst ^ src) & 3))
25*4882a593Smuzhiyun 			goto restup;
26*4882a593Smuzhiyun 
27*4882a593Smuzhiyun 		if (dst & 1) {
28*4882a593Smuzhiyun 			*(char *)dst++ = *(char *)src++;
29*4882a593Smuzhiyun 			count--;
30*4882a593Smuzhiyun 		}
31*4882a593Smuzhiyun 		if (dst & 2) {
32*4882a593Smuzhiyun 			*(short *)dst = *(short *)src;
33*4882a593Smuzhiyun 			src += 2;
34*4882a593Smuzhiyun 			dst += 2;
35*4882a593Smuzhiyun 			count -= 2;
36*4882a593Smuzhiyun 		}
37*4882a593Smuzhiyun 		while (count > 3) {
38*4882a593Smuzhiyun 			*(long *)dst = *(long *)src;
39*4882a593Smuzhiyun 			src += 4;
40*4882a593Smuzhiyun 			dst += 4;
41*4882a593Smuzhiyun 			count -= 4;
42*4882a593Smuzhiyun 		}
43*4882a593Smuzhiyun restup:
44*4882a593Smuzhiyun 		while (count--)
45*4882a593Smuzhiyun 			*(char *)dst++ = *(char *)src++;
46*4882a593Smuzhiyun 	} else {
47*4882a593Smuzhiyun 		dst = (unsigned long) d + count;
48*4882a593Smuzhiyun 		src = (unsigned long) s + count;
49*4882a593Smuzhiyun 
50*4882a593Smuzhiyun 		if ((count < 8) || ((dst ^ src) & 3))
51*4882a593Smuzhiyun 			goto restdown;
52*4882a593Smuzhiyun 
53*4882a593Smuzhiyun 		if (dst & 1) {
54*4882a593Smuzhiyun 			src--;
55*4882a593Smuzhiyun 			dst--;
56*4882a593Smuzhiyun 			count--;
57*4882a593Smuzhiyun 			*(char *)dst = *(char *)src;
58*4882a593Smuzhiyun 		}
59*4882a593Smuzhiyun 		if (dst & 2) {
60*4882a593Smuzhiyun 			src -= 2;
61*4882a593Smuzhiyun 			dst -= 2;
62*4882a593Smuzhiyun 			count -= 2;
63*4882a593Smuzhiyun 			*(short *)dst = *(short *)src;
64*4882a593Smuzhiyun 		}
65*4882a593Smuzhiyun 		while (count > 3) {
66*4882a593Smuzhiyun 			src -= 4;
67*4882a593Smuzhiyun 			dst -= 4;
68*4882a593Smuzhiyun 			count -= 4;
69*4882a593Smuzhiyun 			*(long *)dst = *(long *)src;
70*4882a593Smuzhiyun 		}
71*4882a593Smuzhiyun restdown:
72*4882a593Smuzhiyun 		while (count--) {
73*4882a593Smuzhiyun 			src--;
74*4882a593Smuzhiyun 			dst--;
75*4882a593Smuzhiyun 			*(char *)dst = *(char *)src;
76*4882a593Smuzhiyun 		}
77*4882a593Smuzhiyun 	}
78*4882a593Smuzhiyun 
79*4882a593Smuzhiyun 	return d;
80*4882a593Smuzhiyun }
81