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 __HAVE_ARCH_MEMSET
34 #ifndef CONFIG_OPT_LIB_FUNCTION
35 void *memset(void *v_src, int c, __kernel_size_t n)
36 {
37 char *src = v_src;
38
39 /* Truncate c to 8 bits */
40 c = (c & 0xFF);
41
42 /* Simple, byte oriented memset or the rest of count. */
43 while (n--)
44 *src++ = c;
45
46 return v_src;
47 }
48 #else /* CONFIG_OPT_LIB_FUNCTION */
49 void *memset(void *v_src, int c, __kernel_size_t n)
50 {
51 char *src = v_src;
52 uint32_t *i_src;
53 uint32_t w32 = 0;
54
55 /* Truncate c to 8 bits */
56 c = (c & 0xFF);
57
58 if (unlikely(c)) {
59 /* Make a repeating word out of it */
60 w32 = c;
61 w32 |= w32 << 8;
62 w32 |= w32 << 16;
63 }
64
65 if (likely(n >= 4)) {
66 /* Align the destination to a word boundary */
67 /* This is done in an endian independent manner */
68 switch ((unsigned) src & 3) {
69 case 1:
70 *src++ = c;
71 --n;
72 case 2:
73 *src++ = c;
74 --n;
75 case 3:
76 *src++ = c;
77 --n;
78 }
79
80 i_src = (void *)src;
81
82 /* Do as many full-word copies as we can */
83 for (; n >= 4; n -= 4)
84 *i_src++ = w32;
85
86 src = (void *)i_src;
87 }
88
89 /* Simple, byte oriented memset or the rest of count. */
90 while (n--)
91 *src++ = c;
92
93 return v_src;
94 }
95 #endif /* CONFIG_OPT_LIB_FUNCTION */
96 EXPORT_SYMBOL(memset);
97 #endif /* __HAVE_ARCH_MEMSET */