OpenCores
URL https://opencores.org/ocsvn/openrisc_me/openrisc_me/trunk

Subversion Repositories openrisc_me

[/] [openrisc/] [trunk/] [gnu-src/] [newlib-1.17.0/] [newlib/] [libc/] [string/] [memset.c] - Blame information for rev 158

Details | Compare with Previous | View Log

Line No. Rev Author Line
1 148 jeremybenn
/*
2
FUNCTION
3
        <<memset>>---set an area of memory
4
 
5
INDEX
6
        memset
7
 
8
ANSI_SYNOPSIS
9
        #include <string.h>
10
        void *memset(void *<[dst]>, int <[c]>, size_t <[length]>);
11
 
12
TRAD_SYNOPSIS
13
        #include <string.h>
14
        void *memset(<[dst]>, <[c]>, <[length]>)
15
        void *<[dst]>;
16
        int <[c]>;
17
        size_t <[length]>;
18
 
19
DESCRIPTION
20
        This function converts the argument <[c]> into an unsigned
21
        char and fills the first <[length]> characters of the array
22
        pointed to by <[dst]> to the value.
23
 
24
RETURNS
25
        <<memset>> returns the value of <[dst]>.
26
 
27
PORTABILITY
28
<<memset>> is ANSI C.
29
 
30
    <<memset>> requires no supporting OS subroutines.
31
 
32
QUICKREF
33
        memset ansi pure
34
*/
35
 
36
#include <string.h>
37
 
38
#define LBLOCKSIZE (sizeof(long))
39
#define UNALIGNED(X)   ((long)X & (LBLOCKSIZE - 1))
40
#define TOO_SMALL(LEN) ((LEN) < LBLOCKSIZE)
41
 
42
_PTR
43
_DEFUN (memset, (m, c, n),
44
        _PTR m _AND
45
        int c _AND
46
        size_t n)
47
{
48
  char *s = (char *) m;
49
 
50
#if !defined(PREFER_SIZE_OVER_SPEED) && !defined(__OPTIMIZE_SIZE__)
51
  int i;
52
  unsigned long buffer;
53
  unsigned long *aligned_addr;
54
  unsigned int d = c & 0xff;    /* To avoid sign extension, copy C to an
55
                                   unsigned variable.  */
56
 
57
  while (UNALIGNED (s))
58
    {
59
      if (n--)
60
        *s++ = (char) c;
61
      else
62
        return m;
63
    }
64
 
65
  if (!TOO_SMALL (n))
66
    {
67
      /* If we get this far, we know that n is large and s is word-aligned. */
68
      aligned_addr = (unsigned long *) s;
69
 
70
      /* Store D into each char sized location in BUFFER so that
71
         we can set large blocks quickly.  */
72
      buffer = (d << 8) | d;
73
      buffer |= (buffer << 16);
74
      for (i = 32; i < LBLOCKSIZE * 8; i <<= 1)
75
        buffer = (buffer << i) | buffer;
76
 
77
      /* Unroll the loop.  */
78
      while (n >= LBLOCKSIZE*4)
79
        {
80
          *aligned_addr++ = buffer;
81
          *aligned_addr++ = buffer;
82
          *aligned_addr++ = buffer;
83
          *aligned_addr++ = buffer;
84
          n -= 4*LBLOCKSIZE;
85
        }
86
 
87
      while (n >= LBLOCKSIZE)
88
        {
89
          *aligned_addr++ = buffer;
90
          n -= LBLOCKSIZE;
91
        }
92
      /* Pick up the remainder with a bytewise loop.  */
93
      s = (char*)aligned_addr;
94
    }
95
 
96
#endif /* not PREFER_SIZE_OVER_SPEED */
97
 
98
  while (n--)
99
    *s++ = (char) c;
100
 
101
  return m;
102
}

powered by: WebSVN 2.1.0

© copyright 1999-2024 OpenCores.org, equivalent to Oliscience, all rights reserved. OpenCores®, registered trademark.