source: SVN/cambria/redboot/packages/infra/current/src/memset.c @ 1

Last change on this file since 1 was 1, checked in by Tim Harvey, 2 years ago

restored latest version of files from server backup

Signed-off-by: Tim Harvey <tharvey@…>

File size: 5.8 KB
Line 
1/*===========================================================================
2//
3//      memset.c
4//
5//      ANSI standard memset() routine
6//
7//==========================================================================
8//####ECOSGPLCOPYRIGHTBEGIN####
9// -------------------------------------------
10// This file is part of eCos, the Embedded Configurable Operating System.
11// Copyright (C) 1998, 1999, 2000, 2001, 2002 Red Hat, Inc.
12//
13// eCos is free software; you can redistribute it and/or modify it under
14// the terms of the GNU General Public License as published by the Free
15// Software Foundation; either version 2 or (at your option) any later version.
16//
17// eCos is distributed in the hope that it will be useful, but WITHOUT ANY
18// WARRANTY; without even the implied warranty of MERCHANTABILITY or
19// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
20// for more details.
21//
22// You should have received a copy of the GNU General Public License along
23// with eCos; if not, write to the Free Software Foundation, Inc.,
24// 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
25//
26// As a special exception, if other files instantiate templates or use macros
27// or inline functions from this file, or you compile this file and link it
28// with other works to produce a work based on this file, this file does not
29// by itself cause the resulting work to be covered by the GNU General Public
30// License. However the source code for this file must still be made available
31// in accordance with section (3) of the GNU General Public License.
32//
33// This exception does not invalidate any other reasons why a work based on
34// this file might be covered by the GNU General Public License.
35//
36// Alternative licenses for eCos may be arranged by contacting Red Hat, Inc.
37// at http://sources.redhat.com/ecos/ecos-license/
38// -------------------------------------------
39//####ECOSGPLCOPYRIGHTEND####
40//==========================================================================
41//#####DESCRIPTIONBEGIN####
42//
43// Author(s):   jlarmour
44// Contributors:  jlarmour
45// Date:        1998-06-04
46// Purpose:     This file implements the ANSI memset() function
47// Description: This file implements the memset() function defined in ANSI para
48//              7.11.6.1. This is implemented in the kernel rather than the
49//              C library due to it being required by gcc whether or not the
50//              C library has been configured in.
51//
52//####DESCRIPTIONEND####
53//
54//==========================================================================*/
55
56
57/* INCLUDES */
58
59#include <pkgconf/infra.h>      /* Configuration of infra package */
60
61#include <cyg/infra/cyg_type.h> /* Common type definitions */
62#include <cyg/infra/cyg_trac.h> /* Tracing support */
63#include <cyg/infra/cyg_ass.h>  /* Assertion support */
64#include <stddef.h>             /* Compiler defns such as size_t, NULL etc. */
65
66/* MACROS */
67
68/* Nonzero if X is not aligned on a word boundary. */
69#define CYG_STR_UNALIGNED(X) ((CYG_WORD)(X) & (sizeof (CYG_WORD) - 1))
70
71/* How many bytes are copied each iteration of the word copy loop in the
72 * optimised string implementation
73 */
74#define CYG_STR_OPT_LITTLEBLOCKSIZE (sizeof (CYG_WORD))
75
76/* EXPORTED SYMBOLS */
77
78externC void *
79memset( void *s, int c, size_t n ) __attribute__ ((weak, alias("_memset")));
80
81/* FUNCTIONS */
82
83void *
84_memset( void *s, int c, size_t n )
85{
86#if defined(CYGIMP_INFRA_PREFER_SMALL_TO_FAST_MEMSET) || defined(__OPTIMIZE_SIZE__)
87    char *char_ptr = (char *)s;
88   
89#ifdef CYG_TRACING_FIXED
90    CYG_REPORT_FUNCNAMETYPE( "_memset", "returning %08x" );
91    CYG_REPORT_FUNCARG3( "s=%08x, c=%d, n=%d", s, c, n );
92
93    if (n != 0)
94    {
95        CYG_CHECK_DATA_PTR( char_ptr, "s is not a valid pointer!" );
96        CYG_CHECK_DATA_PTR( (&char_ptr[n-1]), "s+n-1 is not a valid address!" );
97    }
98#endif
99
100    while (n-- != 0)
101    {
102        *char_ptr++ = (char) c;
103    }
104   
105#ifdef CYG_TRACING_FIXED
106    CYG_REPORT_RETVAL( s );
107#endif
108    return s;
109#else
110    char *char_ptr = (char *)s;
111    cyg_ucount8 count;
112    CYG_WORD buffer;
113    CYG_WORD *aligned_addr;
114    char *unaligned_addr;
115   
116#ifdef CYG_TRACING_FIXED
117    CYG_REPORT_FUNCNAMETYPE( "_memset", "returning %08x" );
118    CYG_REPORT_FUNCARG3( "s=%08x, c=%d, n=%d", s, c, n );
119
120    if (n != 0)
121    {
122        CYG_CHECK_DATA_PTR( s, "s is not a valid pointer!" );
123        CYG_CHECK_DATA_PTR( (char *)s+n-1, "s+n-1 is not a valid address!" );
124    }
125#endif
126
127    if (n < sizeof(CYG_WORD) || CYG_STR_UNALIGNED (s))
128    {
129        while (n-- != 0)
130        {
131            *char_ptr++ = (char) c;
132        }
133#ifdef CYG_TRACING_FIXED
134        CYG_REPORT_RETVAL( s );
135#endif
136        return s;
137    }
138   
139    /* If we get this far, we know that n is large and s is word-aligned. */
140   
141    aligned_addr = (CYG_WORD *)s;
142   
143    /* Store C into each char sized location in BUFFER so that
144     * we can set large blocks quickly.
145     */
146    c &= 0xff;
147    if (CYG_STR_OPT_LITTLEBLOCKSIZE == 4)
148    {
149        buffer = (c << 8) | c;
150        buffer |= (buffer << 16);
151    }
152    else
153    {
154        buffer = 0;
155        for (count = 0; count < CYG_STR_OPT_LITTLEBLOCKSIZE; count++)
156            buffer = (buffer << 8) | c;
157    }
158   
159    while (n >= CYG_STR_OPT_LITTLEBLOCKSIZE*4)
160    {
161        *aligned_addr++ = buffer;
162        *aligned_addr++ = buffer;
163        *aligned_addr++ = buffer;
164        *aligned_addr++ = buffer;
165        n -= 4*CYG_STR_OPT_LITTLEBLOCKSIZE;
166    }
167   
168    while (n >= CYG_STR_OPT_LITTLEBLOCKSIZE)
169    {
170        *aligned_addr++ = buffer;
171        n -= CYG_STR_OPT_LITTLEBLOCKSIZE;
172    }
173   
174    /* Pick up the remainder with a bytewise loop. */
175    unaligned_addr = (char*)aligned_addr;
176    while (n)
177    {
178        *unaligned_addr++ = (char)c;
179        n--;
180    }
181   
182#ifdef CYG_TRACING_FIXED
183    CYG_REPORT_RETVAL( s );
184#endif
185    return s;
186#endif /* not defined(CYGIMP_PREFER_SMALL_TO_FAST_MEMSET) ||
187        * defined(__OPTIMIZE_SIZE__) */
188} /* _memset() */
189
190/* EOF memset.c */
Note: See TracBrowser for help on using the repository browser.