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
  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 */