1 /*
2 * Copyright (C) 2008-2009 Michal Simek <monstr@monstr.eu>
3 * Copyright (C) 2008-2009 PetaLogix
4 * Copyright (C) 2007 John Williams
5 *
6 * Reasonably optimised generic C-code for memset on Microblaze
7 * This is generic C code to do efficient, alignment-aware memcpy.
8 *
9 * It is based on demo code originally Copyright 2001 by Intel Corp, taken from
10 * http://www.embedded.com/showArticle.jhtml?articleID=19205567
11 *
12 * Attempts were made, unsuccessfully, to contact the original
13 * author of this code (Michael Morrow, Intel). Below is the original
14 * copyright notice.
15 *
16 * This software has been developed by Intel Corporation.
17 * Intel specifically disclaims all warranties, express or
18 * implied, and all liability, including consequential and
19 * other indirect damages, for the use of this program, including
20 * liability for infringement of any proprietary rights,
21 * and including the warranties of merchantability and fitness
22 * for a particular purpose. Intel does not assume any
23 * responsibility for and errors which may appear in this program
24 * not any responsibility to update it.
25 */
26
27 #include <linux/export.h>
28 #include <linux/types.h>
29 #include <linux/stddef.h>
30 #include <linux/compiler.h>
31 #include <linux/string.h>
32
33 #ifdef CONFIG_OPT_LIB_FUNCTION
memset(void * v_src,int c,__kernel_size_t n)34 void *memset(void *v_src, int c, __kernel_size_t n)
35 {
36 char *src = v_src;
37 uint32_t *i_src;
38 uint32_t w32 = 0;
39
40 /* Truncate c to 8 bits */
41 c = (c & 0xFF);
42
43 if (unlikely(c)) {
44 /* Make a repeating word out of it */
45 w32 = c;
46 w32 |= w32 << 8;
47 w32 |= w32 << 16;
48 }
49
50 if (likely(n >= 4)) {
51 /* Align the destination to a word boundary */
52 /* This is done in an endian independent manner */
53 switch ((unsigned) src & 3) {
54 case 1:
55 *src++ = c;
56 --n;
57 fallthrough;
58 case 2:
59 *src++ = c;
60 --n;
61 fallthrough;
62 case 3:
63 *src++ = c;
64 --n;
65 }
66
67 i_src = (void *)src;
68
69 /* Do as many full-word copies as we can */
70 for (; n >= 4; n -= 4)
71 *i_src++ = w32;
72
73 src = (void *)i_src;
74 }
75
76 /* Simple, byte oriented memset or the rest of count. */
77 switch (n) {
78 case 3:
79 *src++ = c;
80 fallthrough;
81 case 2:
82 *src++ = c;
83 fallthrough;
84 case 1:
85 *src++ = c;
86 break;
87 default:
88 break;
89 }
90
91 return v_src;
92 }
93 EXPORT_SYMBOL(memset);
94 #endif /* CONFIG_OPT_LIB_FUNCTION */
95