1 | /* Copyright (c) 2009 Xilinx, Inc. All rights reserved. |
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2 | |
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3 | Redistribution and use in source and binary forms, with or without |
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4 | modification, are permitted provided that the following conditions are |
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5 | met: |
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6 | |
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7 | 1. Redistributions source code must retain the above copyright notice, |
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8 | this list of conditions and the following disclaimer. |
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9 | |
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10 | 2. Redistributions in binary form must reproduce the above copyright |
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11 | notice, this list of conditions and the following disclaimer in the |
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12 | documentation and/or other materials provided with the distribution. |
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13 | |
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14 | 3. Neither the name of Xilinx nor the names of its contributors may be |
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15 | used to endorse or promote products derived from this software without |
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16 | specific prior written permission. |
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17 | |
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18 | THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER AND CONTRIBUTORS "AS |
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19 | IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED |
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20 | TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A |
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21 | PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
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22 | HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
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23 | SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED |
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24 | TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR |
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25 | PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF |
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26 | LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING |
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27 | NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS |
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28 | SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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29 | |
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30 | |
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31 | FUNCTION |
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32 | <<strlen>>---character string length |
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33 | |
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34 | INDEX |
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35 | strlen |
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36 | |
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37 | SYNOPSIS |
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38 | #include <string.h> |
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39 | size_t strlen(const char *<[str]>); |
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40 | |
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41 | DESCRIPTION |
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42 | The <<strlen>> function works out the length of the string |
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43 | starting at <<*<[str]>>> by counting chararacters until it |
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44 | reaches a <<NULL>> character. |
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45 | |
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46 | RETURNS |
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47 | <<strlen>> returns the character count. |
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48 | |
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49 | PORTABILITY |
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50 | <<strlen>> is ANSI C. |
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51 | |
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52 | <<strlen>> requires no supporting OS subroutines. |
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53 | |
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54 | QUICKREF |
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55 | strlen ansi pure |
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56 | */ |
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57 | |
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58 | #include <_ansi.h> |
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59 | #include <string.h> |
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60 | #include <limits.h> |
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61 | |
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62 | #define LBLOCKSIZE (sizeof (long)) |
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63 | #define UNALIGNED(X) ((long)X & (LBLOCKSIZE - 1)) |
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64 | |
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65 | #if LONG_MAX == 2147483647L |
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66 | #define DETECTNULL(X) (((X) - 0x01010101) & ~(X) & 0x80808080) |
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67 | #else |
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68 | #if LONG_MAX == 9223372036854775807L |
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69 | /* Nonzero if X (a long int) contains a NULL byte. */ |
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70 | #define DETECTNULL(X) (((X) - 0x0101010101010101) & ~(X) & 0x8080808080808080) |
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71 | #else |
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72 | #error long int is not a 32bit or 64bit type. |
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73 | #endif |
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74 | #endif |
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75 | |
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76 | #ifndef DETECTNULL |
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77 | #error long int is not a 32bit or 64bit byte |
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78 | #endif |
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79 | |
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80 | size_t |
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81 | strlen (const char *str) |
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82 | { |
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83 | |
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84 | #ifndef HAVE_HW_PCMP |
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85 | |
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86 | #if defined(PREFER_SIZE_OVER_SPEED) || defined(__OPTIMIZE_SIZE__) |
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87 | const char *start = str; |
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88 | |
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89 | while (*str) |
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90 | str++; |
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91 | |
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92 | return str - start; |
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93 | #else |
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94 | const char *start = str; |
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95 | unsigned long *aligned_addr; |
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96 | |
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97 | if (!UNALIGNED (str)) |
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98 | { |
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99 | /* If the string is word-aligned, we can check for the presence of |
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100 | a null in each word-sized block. */ |
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101 | aligned_addr = (unsigned long*)str; |
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102 | while (!DETECTNULL (*aligned_addr)) |
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103 | aligned_addr++; |
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104 | |
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105 | /* Once a null is detected, we check each byte in that block for a |
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106 | precise position of the null. */ |
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107 | str = (char*)aligned_addr; |
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108 | } |
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109 | |
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110 | while (*str) |
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111 | str++; |
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112 | return str - start; |
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113 | #endif /* not PREFER_SIZE_OVER_SPEED */ |
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114 | |
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115 | #else |
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116 | |
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117 | #include "mb_endian.h" |
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118 | |
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119 | asm volatile (" \n\ |
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120 | or r9, r0, r0 /* Index register */ \n\ |
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121 | check_alignment: \n\ |
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122 | andi r3, r5, 3 \n\ |
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123 | bnei r3, align_arg \n\ |
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124 | len_loop: \n" |
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125 | LOAD4BYTES("r3", "r5", "r9") |
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126 | " \n\ |
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127 | pcmpbf r4, r3, r0 \n\ |
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128 | bnei r4, end_len \n\ |
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129 | brid len_loop \n\ |
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130 | addik r9, r9, 4 \n\ |
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131 | end_len: \n\ |
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132 | lbu r3, r5, r9 \n\ |
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133 | beqi r3, done_len \n\ |
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134 | brid end_len \n\ |
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135 | addik r9, r9, 1 \n\ |
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136 | done_len: \n\ |
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137 | rtsd r15, 8 \n\ |
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138 | or r3, r0, r9 /* Return len */ \n\ |
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139 | align_arg: \n\ |
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140 | rsubik r10, r3, 4 \n\ |
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141 | align_loop: \n\ |
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142 | lbu r3, r5, r9 \n\ |
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143 | beqid r3, done_len \n\ |
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144 | addik r10, r10, -1 \n\ |
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145 | bneid r10, align_loop \n\ |
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146 | addik r9, r9, 1 \n\ |
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147 | bri len_loop"); |
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148 | |
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149 | #endif /* ! HAVE_HW_PCMP */ |
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150 | } |
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