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1 /*=========================================================================== |
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2 // |
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3 // memset.c |
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4 // |
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5 // ANSI standard memset() routine |
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6 // |
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7 //========================================================================== |
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8 //####COPYRIGHTBEGIN#### |
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9 // |
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10 // ------------------------------------------- |
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11 // The contents of this file are subject to the Cygnus eCos Public License |
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12 // Version 1.0 (the "License"); you may not use this file except in |
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13 // compliance with the License. You may obtain a copy of the License at |
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14 // http://sourceware.cygnus.com/ecos |
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15 // |
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16 // Software distributed under the License is distributed on an "AS IS" |
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17 // basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See the |
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18 // License for the specific language governing rights and limitations under |
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19 // the License. |
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20 // |
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21 // The Original Code is eCos - Embedded Cygnus Operating System, released |
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22 // September 30, 1998. |
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23 // |
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24 // The Initial Developer of the Original Code is Cygnus. Portions created |
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25 // by Cygnus are Copyright (C) 1998,1999 Cygnus Solutions. All Rights Reserved. |
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26 // ------------------------------------------- |
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27 // |
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28 //####COPYRIGHTEND#### |
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29 //========================================================================== |
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30 //#####DESCRIPTIONBEGIN#### |
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31 // |
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32 // Author(s): jlarmour |
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33 // Contributors: jlarmour |
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34 // Date: 1998-06-04 |
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35 // Purpose: This file implements the ANSI memset() function |
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36 // Description: This file implements the memset() function defined in ANSI para |
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37 // 7.11.6.1. This is implemented in the kernel rather than the |
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38 // C library due to it being required by gcc whether or not the |
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39 // C library has been configured in. |
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40 // |
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41 //####DESCRIPTIONEND#### |
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42 // |
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43 //==========================================================================*/ |
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44 |
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45 |
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46 /* INCLUDES */ |
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47 |
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48 #include <pkgconf/infra.h> /* Configuration of infra package */ |
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49 |
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50 #include <cyg/infra/cyg_type.h> /* Common type definitions */ |
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51 #include <cyg/infra/cyg_trac.h> /* Tracing support */ |
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52 #include <cyg/infra/cyg_ass.h> /* Assertion support */ |
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53 #include <stddef.h> /* Compiler defns such as size_t, NULL etc. */ |
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54 |
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55 /* MACROS */ |
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56 |
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57 /* Nonzero if X is not aligned on a word boundary. */ |
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58 #define CYG_STR_UNALIGNED(X) ((CYG_WORD)(X) & (sizeof (CYG_WORD) - 1)) |
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59 |
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60 /* How many bytes are copied each iteration of the word copy loop in the |
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61 * optimised string implementation |
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62 */ |
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63 #define CYG_STR_OPT_LITTLEBLOCKSIZE (sizeof (CYG_WORD)) |
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64 |
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65 /* EXPORTED SYMBOLS */ |
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66 |
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67 externC void * |
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68 memset( void *s, int c, size_t n ) __attribute__ ((weak, alias("_memset"))); |
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69 |
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70 /* FUNCTIONS */ |
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71 |
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72 void * |
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73 _memset( void *s, int c, size_t n ) |
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74 { |
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75 #if defined(CYGIMP_INFRA_PREFER_SMALL_TO_FAST_MEMSET) || defined(__OPTIMIZE_SIZE__) |
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76 char *char_ptr = (char *)s; |
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77 |
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78 #ifdef CYG_TRACING_FIXED |
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79 CYG_REPORT_FUNCNAMETYPE( "_memset", "returning %08x" ); |
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80 CYG_REPORT_FUNCARG3( "s=%08x, c=%d, n=%d", s, c, n ); |
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81 |
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82 if (n != 0) |
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83 { |
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84 CYG_CHECK_DATA_PTR( char_ptr, "s is not a valid pointer!" ); |
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85 CYG_CHECK_DATA_PTR( (&char_ptr[n-1]), "s+n-1 is not a valid address!" ); |
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86 } |
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87 #endif |
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88 |
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89 while (n-- != 0) |
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90 { |
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91 *char_ptr++ = (char) c; |
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92 } |
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93 |
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94 #ifdef CYG_TRACING_FIXED |
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95 CYG_REPORT_RETVAL( s ); |
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96 #endif |
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97 return s; |
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98 #else |
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99 char *char_ptr = (char *)s; |
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100 cyg_ucount8 count; |
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101 CYG_WORD buffer; |
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102 CYG_WORD *aligned_addr; |
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103 char *unaligned_addr; |
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104 |
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105 #ifdef CYG_TRACING_FIXED |
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106 CYG_REPORT_FUNCNAMETYPE( "_memset", "returning %08x" ); |
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107 CYG_REPORT_FUNCARG3( "s=%08x, c=%d, n=%d", s, c, n ); |
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108 |
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109 if (n != 0) |
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110 { |
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111 CYG_CHECK_DATA_PTR( s, "s is not a valid pointer!" ); |
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112 CYG_CHECK_DATA_PTR( (char *)s+n-1, "s+n-1 is not a valid address!" ); |
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113 } |
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114 #endif |
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115 |
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116 if (n < sizeof(CYG_WORD) || CYG_STR_UNALIGNED (s)) |
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117 { |
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118 while (n-- != 0) |
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119 { |
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120 *char_ptr++ = (char) c; |
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121 } |
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122 #ifdef CYG_TRACING_FIXED |
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123 CYG_REPORT_RETVAL( s ); |
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124 #endif |
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125 return s; |
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126 } |
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127 |
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128 /* If we get this far, we know that n is large and s is word-aligned. */ |
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129 |
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130 aligned_addr = (CYG_WORD *)s; |
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131 |
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132 /* Store C into each char sized location in BUFFER so that |
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133 * we can set large blocks quickly. |
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134 */ |
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135 c &= 0xff; |
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136 if (CYG_STR_OPT_LITTLEBLOCKSIZE == 4) |
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137 { |
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138 buffer = (c << 8) | c; |
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139 buffer |= (buffer << 16); |
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140 } |
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141 else |
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142 { |
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143 buffer = 0; |
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144 for (count = 0; count < CYG_STR_OPT_LITTLEBLOCKSIZE; count++) |
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145 buffer = (buffer << 8) | c; |
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146 } |
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147 |
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148 while (n >= CYG_STR_OPT_LITTLEBLOCKSIZE*4) |
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149 { |
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150 *aligned_addr++ = buffer; |
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151 *aligned_addr++ = buffer; |
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152 *aligned_addr++ = buffer; |
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153 *aligned_addr++ = buffer; |
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154 n -= 4*CYG_STR_OPT_LITTLEBLOCKSIZE; |
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155 } |
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156 |
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157 while (n >= CYG_STR_OPT_LITTLEBLOCKSIZE) |
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158 { |
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159 *aligned_addr++ = buffer; |
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160 n -= CYG_STR_OPT_LITTLEBLOCKSIZE; |
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161 } |
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162 |
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163 /* Pick up the remainder with a bytewise loop. */ |
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164 unaligned_addr = (char*)aligned_addr; |
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165 while (n) |
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166 { |
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167 *unaligned_addr++ = (char)c; |
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168 n--; |
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169 } |
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170 |
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171 #ifdef CYG_TRACING_FIXED |
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172 CYG_REPORT_RETVAL( s ); |
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173 #endif |
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174 return s; |
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175 #endif /* not defined(CYGIMP_PREFER_SMALL_TO_FAST_MEMSET) || |
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176 * defined(__OPTIMIZE_SIZE__) */ |
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177 } /* _memset() */ |
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178 |
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179 /* EOF memset.c */ |
