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
34void *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}
93EXPORT_SYMBOL(memset);
94#endif /* CONFIG_OPT_LIB_FUNCTION */
95