LXR linux/arch/microblaze/lib/memset.c

   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
  35void *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 */
  49void *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 */
  96EXPORT_SYMBOL(memset);
  97#endif /* __HAVE_ARCH_MEMSET */
  98