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 | <<strcmp>>---character string compare |
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33 | |
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34 | INDEX |
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35 | strcmp |
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36 | |
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37 | SYNOPSIS |
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38 | #include <string.h> |
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39 | int strcmp(const char *<[a]>, const char *<[b]>); |
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40 | |
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41 | DESCRIPTION |
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42 | <<strcmp>> compares the string at <[a]> to |
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43 | the string at <[b]>. |
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44 | |
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45 | RETURNS |
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46 | If <<*<[a]>>> sorts lexicographically after <<*<[b]>>>, |
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47 | <<strcmp>> returns a number greater than zero. If the two |
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48 | strings match, <<strcmp>> returns zero. If <<*<[a]>>> |
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49 | sorts lexicographically before <<*<[b]>>>, <<strcmp>> returns a |
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50 | number less than zero. |
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51 | |
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52 | PORTABILITY |
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53 | <<strcmp>> is ANSI C. |
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54 | |
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55 | <<strcmp>> requires no supporting OS subroutines. |
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56 | |
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57 | QUICKREF |
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58 | strcmp ansi pure |
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59 | */ |
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60 | |
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61 | #include <string.h> |
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62 | #include <limits.h> |
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63 | |
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64 | /* Nonzero if either X or Y is not aligned on a "long" boundary. */ |
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65 | #define UNALIGNED(X, Y) \ |
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66 | (((long)X & (sizeof (long) - 1)) | ((long)Y & (sizeof (long) - 1))) |
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67 | |
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68 | /* DETECTNULL returns nonzero if (long)X contains a NULL byte. */ |
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69 | #if LONG_MAX == 2147483647L |
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70 | #define DETECTNULL(X) (((X) - 0x01010101) & ~(X) & 0x80808080) |
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71 | #else |
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72 | #if LONG_MAX == 9223372036854775807L |
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73 | #define DETECTNULL(X) (((X) - 0x0101010101010101) & ~(X) & 0x8080808080808080) |
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74 | #else |
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75 | #error long int is not a 32bit or 64bit type. |
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76 | #endif |
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77 | #endif |
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78 | |
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79 | #ifndef DETECTNULL |
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80 | #error long int is not a 32bit or 64bit byte |
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81 | #endif |
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82 | |
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83 | int |
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84 | strcmp (const char *s1, |
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85 | const char *s2) |
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86 | { |
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87 | |
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88 | #ifndef HAVE_HW_PCMP |
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89 | |
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90 | #if defined(PREFER_SIZE_OVER_SPEED) || defined(__OPTIMIZE_SIZE__) |
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91 | while (*s1 != '\0' && *s1 == *s2) |
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92 | { |
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93 | s1++; |
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94 | s2++; |
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95 | } |
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96 | |
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97 | return (*(unsigned char *) s1) - (*(unsigned char *) s2); |
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98 | #else |
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99 | unsigned long *a1; |
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100 | unsigned long *a2; |
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101 | |
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102 | /* If s1 or s2 are unaligned, then compare bytes. */ |
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103 | if (!UNALIGNED (s1, s2)) |
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104 | { |
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105 | /* If s1 and s2 are word-aligned, compare them a word at a time. */ |
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106 | a1 = (unsigned long*)s1; |
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107 | a2 = (unsigned long*)s2; |
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108 | while (*a1 == *a2) |
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109 | { |
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110 | /* To get here, *a1 == *a2, thus if we find a null in *a1, |
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111 | then the strings must be equal, so return zero. */ |
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112 | if (DETECTNULL (*a1)) |
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113 | return 0; |
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114 | |
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115 | a1++; |
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116 | a2++; |
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117 | } |
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118 | |
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119 | /* A difference was detected in last few bytes of s1, so search bytewise */ |
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120 | s1 = (char*)a1; |
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121 | s2 = (char*)a2; |
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122 | } |
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123 | |
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124 | while (*s1 != '\0' && *s1 == *s2) |
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125 | { |
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126 | s1++; |
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127 | s2++; |
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128 | } |
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129 | return (*(unsigned char *) s1) - (*(unsigned char *) s2); |
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130 | #endif /* not PREFER_SIZE_OVER_SPEED */ |
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131 | |
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132 | #else |
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133 | |
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134 | #include "mb_endian.h" |
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135 | |
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136 | asm volatile (" \n\ |
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137 | or r9, r0, r0 /* Index register */\n\ |
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138 | check_alignment: \n\ |
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139 | andi r3, r5, 3 \n\ |
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140 | andi r4, r6, 3 \n\ |
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141 | bnei r3, try_align_args \n\ |
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142 | bnei r4, regular_strcmp /* At this point we don't have a choice */ \n\ |
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143 | cmp_loop: \n" |
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144 | LOAD4BYTES("r3", "r5", "r9") |
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145 | LOAD4BYTES("r4", "r6", "r9") |
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146 | " \n\ |
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147 | pcmpbf r7, r3, r0 /* See if there is Null byte */ \n\ |
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148 | bnei r7, end_cmp_loop /* IF yes (r7 > 0) use byte compares in end_cmp_loop */ \n\ |
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149 | cmpu r7, r4, r3 /* ELSE compare whole word */ \n\ |
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150 | bnei r7, end_cmp \n\ |
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151 | brid cmp_loop \n\ |
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152 | addik r9, r9, 4 /* delay slot */ \n\ |
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153 | end_cmp_loop: \n\ |
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154 | lbu r3, r5, r9 /* byte compare loop */ \n\ |
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155 | lbu r4, r6, r9 \n\ |
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156 | cmpu r7, r4, r3 /* Compare bytes */ \n\ |
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157 | bnei r7, end_cmp_early \n\ |
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158 | bneid r3, end_cmp_loop /* If reached null on one string, terminate */ \n\ |
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159 | addik r9, r9, 1 /* delay slot */ \n\ |
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160 | end_cmp_early: \n\ |
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161 | rtsd r15, 8 \n\ |
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162 | or r3, r0, r7 \n\ |
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163 | try_align_args: \n\ |
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164 | xor r7, r4, r3 \n\ |
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165 | bnei r7, regular_strcmp /* cannot align args */ \n\ |
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166 | rsubik r10, r3, 4 /* Number of initial bytes to align */ \n\ |
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167 | align_loop: \n\ |
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168 | lbu r3, r5, r9 \n\ |
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169 | lbu r4, r6, r9 \n\ |
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170 | cmpu r7, r4, r3 \n\ |
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171 | bnei r7, end_cmp \n\ |
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172 | beqi r3, end_cmp \n\ |
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173 | addik r10, r10, -1 \n\ |
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174 | beqid r10, cmp_loop \n\ |
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175 | addik r9, r9, 1 \n\ |
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176 | bri align_loop \n\ |
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177 | regular_strcmp: \n\ |
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178 | lbu r3, r5, r9 \n\ |
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179 | lbu r4, r6, r9 \n\ |
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180 | cmpu r7, r4, r3 \n\ |
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181 | bnei r7, end_cmp \n\ |
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182 | beqi r3, end_cmp \n\ |
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183 | brid regular_strcmp \n\ |
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184 | addik r9, r9, 1 \n\ |
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185 | end_cmp: \n\ |
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186 | rtsd r15, 8 \n\ |
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187 | or r3, r0, r7 /* Return strcmp result */"); |
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188 | |
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189 | #endif /* ! HAVE_HW_PCMP */ |
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190 | } |
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191 | |
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