Linux Kernel  3.7.1
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memcpy.c
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1 /*
2  * This file is subject to the terms and conditions of the GNU General Public
3  * License. See the file COPYING in the main directory of this archive
4  * for more details.
5  */
6 
7 #include <linux/module.h>
8 #include <linux/string.h>
9 
10 void *memcpy(void *to, const void *from, size_t n)
11 {
12  void *xto = to;
13  size_t temp, temp1;
14 
15  if (!n)
16  return xto;
17  if ((long)to & 1) {
18  char *cto = to;
19  const char *cfrom = from;
20  *cto++ = *cfrom++;
21  to = cto;
22  from = cfrom;
23  n--;
24  }
25 #if defined(CONFIG_M68000)
26  if ((long)from & 1) {
27  char *cto = to;
28  const char *cfrom = from;
29  for (; n; n--)
30  *cto++ = *cfrom++;
31  return xto;
32  }
33 #endif
34  if (n > 2 && (long)to & 2) {
35  short *sto = to;
36  const short *sfrom = from;
37  *sto++ = *sfrom++;
38  to = sto;
39  from = sfrom;
40  n -= 2;
41  }
42  temp = n >> 2;
43  if (temp) {
44  long *lto = to;
45  const long *lfrom = from;
46 #if defined(CONFIG_M68000) || defined(CONFIG_COLDFIRE)
47  for (; temp; temp--)
48  *lto++ = *lfrom++;
49 #else
50  asm volatile (
51  " movel %2,%3\n"
52  " andw #7,%3\n"
53  " lsrl #3,%2\n"
54  " negw %3\n"
55  " jmp %%pc@(1f,%3:w:2)\n"
56  "4: movel %0@+,%1@+\n"
57  " movel %0@+,%1@+\n"
58  " movel %0@+,%1@+\n"
59  " movel %0@+,%1@+\n"
60  " movel %0@+,%1@+\n"
61  " movel %0@+,%1@+\n"
62  " movel %0@+,%1@+\n"
63  " movel %0@+,%1@+\n"
64  "1: dbra %2,4b\n"
65  " clrw %2\n"
66  " subql #1,%2\n"
67  " jpl 4b"
68  : "=a" (lfrom), "=a" (lto), "=d" (temp), "=&d" (temp1)
69  : "0" (lfrom), "1" (lto), "2" (temp));
70 #endif
71  to = lto;
72  from = lfrom;
73  }
74  if (n & 2) {
75  short *sto = to;
76  const short *sfrom = from;
77  *sto++ = *sfrom++;
78  to = sto;
79  from = sfrom;
80  }
81  if (n & 1) {
82  char *cto = to;
83  const char *cfrom = from;
84  *cto = *cfrom;
85  }
86  return xto;
87 }