1 | /* |
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2 | (C) Copyright 2008 |
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3 | International Business Machines Corporation, |
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4 | All rights reserved. |
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5 | |
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6 | Redistribution and use in source and binary forms, with or without |
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7 | modification, are permitted provided that the following conditions are met: |
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8 | |
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9 | * Redistributions of source code must retain the above copyright notice, |
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10 | this list of conditions and the following disclaimer. |
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11 | * Redistributions in binary form must reproduce the above copyright |
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12 | notice, this list of conditions and the following disclaimer in the |
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13 | documentation and/or other materials provided with the distribution. |
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14 | * Neither the names of the copyright holders nor the names of their |
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15 | contributors may be used to endorse or promote products derived from |
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16 | this software without specific prior written permission. |
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17 | |
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18 | THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 OWNER |
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22 | OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, |
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23 | EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, |
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24 | 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 | #include <spu_intrinsics.h> |
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32 | #include "vec_literal.h" |
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33 | #include <string.h> |
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34 | |
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35 | /* |
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36 | * Supply an inline _strncpy for strcpy/cat and strncpy/cat. Relies on |
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37 | * checklen and lastzero code being optimized out when they are constant |
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38 | * zero values. |
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39 | */ |
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40 | static inline void * _strncpy(char * __restrict__ dest, const char * |
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41 | __restrict__ src, size_t maxlen, int |
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42 | checklen, int lastzero) |
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43 | { |
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44 | int adjust, offset, soffset, doffset, shift; |
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45 | vec_uchar16 *vsrc, *vdest; |
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46 | vec_uchar16 sdata1, sdata2, sdata, shuffle; |
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47 | vec_uchar16 mask1, maskzero, cmp0; |
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48 | vec_uint4 nonzeroes, gathered_cmp, vtmp, vtmp2; |
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49 | vec_uint4 curlen; /* assumes size_t is 4 bytes */ |
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50 | const vec_uint4 val31 = { 31, 31, 31, 31 }; |
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51 | const vec_uint4 val_0123 = { 0x00010203, 0x04050607, 0x08090A0B, 0x0C0D0E0F }; |
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52 | const vec_uchar16 all_ones = { 0xff,0xff,0xff,0xff, 0xff,0xff,0xff,0xff, |
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53 | 0xff,0xff,0xff,0xff, 0xff,0xff,0xff,0xff }; |
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54 | |
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55 | vsrc = (vec_uchar16 *) src; |
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56 | vdest = (vec_uchar16 *) dest; |
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57 | soffset = (int) src & 15; |
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58 | doffset = (int) dest & 15; |
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59 | |
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60 | if (checklen) { |
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61 | /* |
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62 | * Set curlen so it is the number of bytes we would copy if starting |
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63 | * from vdest & ~0xf. |
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64 | * |
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65 | * curlen could probably be replaced by comparing vdest plus some |
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66 | * offset to dest + maxlen, that would help mainly in the while loop |
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67 | * but would lose only one instruction (the curlen -= 16). |
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68 | */ |
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69 | curlen = spu_splats((unsigned int) (maxlen + doffset)); |
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70 | } |
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71 | |
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72 | /* |
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73 | * Setup a shuffle pattern to align the source string with the |
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74 | * alignment of the destination string. |
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75 | */ |
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76 | vtmp = spu_cmpgt(spu_promote(doffset, 0), spu_promote(soffset, 0)); |
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77 | adjust = spu_extract(vtmp, 0); |
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78 | offset = soffset - doffset; |
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79 | offset += adjust & 16; |
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80 | shuffle = spu_splats((unsigned char) offset); |
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81 | shuffle = (vec_uchar16) spu_add((vec_uint4) shuffle, val_0123); |
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82 | |
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83 | vsrc += adjust; |
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84 | sdata1 = *vsrc++; |
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85 | sdata2 = *vsrc++; |
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86 | sdata = spu_shuffle(sdata1, sdata2, shuffle); |
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87 | |
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88 | /* |
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89 | * mask out leading bytes |
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90 | */ |
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91 | mask1 = spu_rlmaskqwbyte(all_ones, -doffset); |
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92 | |
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93 | cmp0 = spu_and(mask1, spu_cmpeq(sdata, 0)); |
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94 | nonzeroes = spu_cntlz(spu_gather(cmp0)); |
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95 | /* |
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96 | * First element of nonzeroes - 15 is the number of leading non-zero |
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97 | * bytes plus 1 for the zero byte. |
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98 | */ |
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99 | if (checklen) { |
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100 | vtmp = spu_add(curlen, 15); |
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101 | vtmp2 = spu_cmpgt(nonzeroes, vtmp); |
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102 | nonzeroes = spu_sel(nonzeroes, vtmp, vtmp2); |
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103 | } |
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104 | |
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105 | vtmp = spu_cmpgt(nonzeroes, val31); |
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106 | /* |
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107 | * Note: using immediate (constant 31) vs a vector value (val31) does |
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108 | * not give different results, and we have to have a vector val31 for |
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109 | * the spu_sel below, so use val31 everywhere. |
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110 | */ |
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111 | vtmp = spu_sel(nonzeroes, val31, vtmp); |
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112 | /* |
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113 | * So vtmp is now min(nonzeroes, 31), the number of bytes + 16 that we |
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114 | * want to copy from the first 16 bytes of the source. |
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115 | */ |
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116 | if (checklen) { |
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117 | curlen = spu_sub(vtmp, curlen); |
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118 | curlen = spu_sub(15, curlen); |
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119 | } |
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120 | |
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121 | /* |
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122 | * We want a right shift 0xff with fill by ones of (vtmp - 15) bytes, but |
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123 | * that doesn't exist so use spu_slqwbyte and vtmp all ones left by |
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124 | * (31 - vtmp). Note: this can also use spu_rlqwbytebc with spu_rlqw. |
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125 | */ |
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126 | shift = spu_extract(spu_sub(val31, vtmp), 0); |
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127 | maskzero = spu_slqwbyte(all_ones, shift); |
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128 | maskzero = spu_and(mask1, maskzero); |
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129 | *vdest = spu_sel(*vdest, sdata, maskzero); |
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130 | |
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131 | vtmp = spu_cmpgt(nonzeroes, val31); |
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132 | if (checklen) { |
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133 | vtmp2 = spu_cmpgt(curlen, 0); |
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134 | vtmp = spu_and(vtmp, vtmp2); |
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135 | } |
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136 | if (spu_extract(vtmp, 0)) { |
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137 | sdata1 = sdata2; |
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138 | sdata2 = *vsrc++; |
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139 | sdata = spu_shuffle(sdata1, sdata2, shuffle); |
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140 | cmp0 = spu_cmpeq(sdata, 0); |
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141 | gathered_cmp = spu_gather(cmp0); |
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142 | /* |
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143 | * Copy 16 bytes at a time. |
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144 | */ |
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145 | while ((spu_extract(gathered_cmp, 0) == 0) && |
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146 | (!checklen || (spu_extract(curlen, 0) > 15))) { |
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147 | if (checklen) |
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148 | curlen = spu_add(curlen, -16); |
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149 | *++vdest = sdata; |
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150 | sdata1 = sdata2; |
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151 | sdata2 = *vsrc++; |
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152 | sdata = spu_shuffle(sdata1, sdata2, shuffle); |
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153 | cmp0 = spu_cmpeq(sdata, 0); |
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154 | gathered_cmp = spu_gather(cmp0); |
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155 | } |
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156 | /* |
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157 | * Copy 0 to 15 trailing bytes, either up to the smaller of curlen or |
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158 | * the number of non-zero bytes. |
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159 | */ |
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160 | nonzeroes = spu_cntlz(gathered_cmp); |
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161 | if (checklen) { |
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162 | vtmp = spu_add(curlen, 15); |
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163 | vtmp2 = spu_cmpgt(nonzeroes, vtmp); |
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164 | nonzeroes = spu_sel(nonzeroes, vtmp, vtmp2); |
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165 | curlen = spu_sub(nonzeroes, curlen); |
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166 | curlen = spu_sub(15, curlen); |
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167 | } |
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168 | shift = spu_extract(spu_sub(val31, nonzeroes), 0); |
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169 | maskzero = spu_slqwbyte(all_ones, shift); |
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170 | ++vdest; |
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171 | *vdest = spu_sel(*vdest, sdata, maskzero); |
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172 | } |
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173 | |
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174 | if (checklen && lastzero) { |
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175 | /* |
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176 | * For strncat. |
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177 | */ |
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178 | dest[maxlen - spu_extract(curlen, 0)] = '\0'; |
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179 | } |
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180 | |
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181 | /* Pad null bytes if the length of the "src" is less than "n" (strncpy). */ |
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182 | if (checklen && !lastzero && spu_extract(curlen, 0)) |
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183 | memset(dest + maxlen - spu_extract(curlen, 0), 0, spu_extract(curlen, 0)); |
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184 | return (dest); |
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185 | } |
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