1 | /* |
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2 | (C) Copyright 2001,2006,2008 |
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3 | International Business Machines Corporation, |
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4 | Sony Computer Entertainment, Incorporated, |
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5 | Toshiba Corporation, |
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6 | |
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7 | All rights reserved. |
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8 | |
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9 | Redistribution and use in source and binary forms, with or without |
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10 | modification, are permitted provided that the following conditions are met: |
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11 | |
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12 | * Redistributions of source code must retain the above copyright notice, |
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13 | this list of conditions and the following disclaimer. |
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14 | * Redistributions in binary form must reproduce the above copyright |
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15 | notice, this list of conditions and the following disclaimer in the |
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16 | documentation and/or other materials provided with the distribution. |
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17 | * Neither the names of the copyright holders nor the names of their |
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18 | contributors may be used to endorse or promote products derived from this |
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19 | software without specific prior written permission. |
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20 | |
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21 | THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" |
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22 | AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
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23 | IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
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24 | ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE |
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25 | LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
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26 | CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
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27 | SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
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28 | INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
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29 | CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
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30 | ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
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31 | POSSIBILITY OF SUCH DAMAGE. |
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32 | */ |
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33 | #include <spu_intrinsics.h> |
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34 | #include <stddef.h> |
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35 | |
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36 | /* |
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37 | * Internal _strncmp_internal for strncmp and memcmp: |
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38 | * |
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39 | * Compare the two strings s1 and s2 of length n. Returns an integer less |
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40 | * than, equal to, or greater than zero if s1 is found, respectively, |
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41 | * to be less than, to match, or be greater than s2. Check for zero bytes |
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42 | * only if check_zeroes is set. In additin, the vector value *end_v will |
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43 | * contain all zeroes if we hit a NUL character that caused the comparison |
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44 | * to complete, *end_v is modified only if check_zeroes is set. |
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45 | */ |
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46 | static inline int |
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47 | _strncmp_internal(const char *s1, const char *s2, size_t n, vec_uint4 |
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48 | *end_v, int check_zeroes) |
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49 | { |
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50 | unsigned int offset1, offset2; |
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51 | vec_int4 n_v; |
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52 | vec_uint4 cnt1_v, cnt2_v, max_cnt_v; |
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53 | vec_uint4 gt_v, lt_v, mask_v, end1_v, end2_v, neq_v, tmp1_v; |
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54 | vec_uint4 shift_n_v, shift_eos_v, max_shift_v; |
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55 | vec_uchar16 shuffle1, shuffle2; |
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56 | vec_uchar16 data1A, data1B, data1, data2A, data2B, data2; |
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57 | vec_uchar16 *ptr1, *ptr2; |
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58 | |
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59 | data1 = data2 = spu_splats((unsigned char)0); |
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60 | |
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61 | ptr1 = (vec_uchar16 *)s1; |
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62 | ptr2 = (vec_uchar16 *)s2; |
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63 | |
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64 | offset1 = (unsigned int)(ptr1) & 15; |
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65 | offset2 = (unsigned int)(ptr2) & 15; |
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66 | |
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67 | shuffle1 = (vec_uchar16) |
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68 | spu_add((vec_uint4)spu_splats((unsigned char)offset1), |
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69 | ((vec_uint4) {0x00010203, 0x04050607, 0x08090A0B, 0x0C0D0E0F})); |
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70 | shuffle2 = (vec_uchar16) |
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71 | spu_add((vec_uint4)spu_splats((unsigned char)offset2), |
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72 | ((vec_uint4) {0x00010203, 0x04050607, 0x08090A0B, 0x0C0D0E0F})); |
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73 | data1A = *ptr1++; |
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74 | data2A = *ptr2++; |
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75 | |
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76 | n_v = spu_promote((int)n, 0); |
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77 | |
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78 | do { |
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79 | data1B = *ptr1++; |
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80 | data2B = *ptr2++; |
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81 | |
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82 | /* |
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83 | * Quadword align each of the input strings so that we operate on full |
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84 | * quadwords. |
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85 | */ |
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86 | data1 = spu_shuffle(data1A, data1B, shuffle1); |
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87 | data2 = spu_shuffle(data2A, data2B, shuffle2); |
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88 | |
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89 | data1A = data1B; |
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90 | data2A = data2B; |
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91 | |
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92 | neq_v = spu_gather(spu_xor(spu_cmpeq(data1, data2), -1)); |
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93 | |
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94 | if (check_zeroes) { |
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95 | end1_v = spu_gather(spu_cmpeq(data1, 0)); |
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96 | end2_v = spu_gather(spu_cmpeq(data2, 0)); |
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97 | *end_v = spu_or(end1_v, end2_v); |
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98 | } |
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99 | |
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100 | n_v = spu_add(n_v, -16); |
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101 | |
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102 | /* |
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103 | * Repeat until either |
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104 | * 1) the character count expired |
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105 | * 2) check_zeroes is set and a null character is discovered in one of |
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106 | * the input strings |
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107 | * 3) the strings do not compare equal |
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108 | */ |
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109 | if (check_zeroes) { |
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110 | tmp1_v = spu_or(*end_v, neq_v); |
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111 | tmp1_v = spu_cmpeq(tmp1_v, 0); |
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112 | } else { |
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113 | tmp1_v = spu_cmpeq(neq_v, 0); |
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114 | } |
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115 | tmp1_v = spu_and(tmp1_v, spu_cmpgt(n_v, 0)); |
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116 | } while (spu_extract(tmp1_v, 0)); |
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117 | |
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118 | /* |
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119 | * Construct a mask to eliminate characters that are not of interest |
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120 | * in the comparison. |
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121 | */ |
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122 | mask_v = spu_splats((unsigned int)0xFFFF); |
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123 | shift_n_v = |
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124 | spu_andc((__vector unsigned int)spu_sub(0, n_v), spu_cmpgt(n_v, -1)); |
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125 | if (check_zeroes) { |
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126 | cnt1_v = spu_cntlz(end1_v); |
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127 | cnt2_v = spu_cntlz(end2_v); |
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128 | max_cnt_v = spu_sel(cnt1_v, cnt2_v, spu_cmpgt(cnt2_v, cnt1_v)); |
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129 | shift_eos_v = spu_sub(32, max_cnt_v); |
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130 | max_shift_v = |
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131 | spu_sel(shift_n_v, shift_eos_v, spu_cmpgt(shift_eos_v, shift_n_v)); |
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132 | mask_v = spu_and(spu_sl(mask_v, spu_extract(max_shift_v, 0)), mask_v); |
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133 | } else { |
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134 | mask_v = spu_and(spu_sl(mask_v, spu_extract(shift_n_v, 0)), mask_v); |
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135 | } |
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136 | |
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137 | /* |
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138 | * Determine if greater then or less then in the case that they are |
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139 | * not equal. gt_v is either 1 (in the case s1 is greater then s2), or |
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140 | * -1 (in the case that s2 is greater then s1). |
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141 | * |
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142 | * There are no byte vector math instructions, so we can't subtract |
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143 | * data1 from data2. |
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144 | */ |
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145 | gt_v = spu_gather(spu_cmpgt(data1, data2)); |
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146 | lt_v = spu_gather(spu_cmpgt(data2, data1)); |
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147 | gt_v = spu_sub(-1, spu_sl(spu_cmpgt(gt_v, lt_v), 1)); |
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148 | |
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149 | /* |
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150 | * Construct a mask to be applied to gt_v if the strings are discovered |
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151 | * to be equal. |
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152 | */ |
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153 | mask_v = spu_cmpeq(spu_and(neq_v, mask_v), 0); |
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154 | return (spu_extract(spu_andc(gt_v, mask_v), 0)); |
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155 | } |
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