1 | /* $NetBSD: in_cksum.c,v 1.10 2005/12/24 23:24:01 perry Exp $ */ |
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2 | |
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3 | /* |
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4 | * Copyright 2001 Wasabi Systems, Inc. |
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5 | * All rights reserved. |
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6 | * |
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7 | * Written by Simon Burge and Eduardo Horvath for Wasabi Systems, Inc. |
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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 |
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11 | * are met: |
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12 | * 1. Redistributions of source code must retain the above copyright |
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13 | * notice, this list of conditions and the following disclaimer. |
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14 | * 2. 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 | * 3. All advertising materials mentioning features or use of this software |
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18 | * must display the following acknowledgement: |
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19 | * This product includes software developed for the NetBSD Project by |
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20 | * Wasabi Systems, Inc. |
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21 | * 4. The name of Wasabi Systems, Inc. may not be used to endorse |
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22 | * or promote products derived from this software without specific prior |
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23 | * written permission. |
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24 | * |
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25 | * THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``AS IS'' AND |
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26 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED |
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27 | * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
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28 | * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL WASABI SYSTEMS, INC |
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29 | * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
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30 | * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
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31 | * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
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32 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
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33 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
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34 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
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35 | * POSSIBILITY OF SUCH DAMAGE. |
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36 | */ |
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37 | |
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38 | /* |
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39 | * Checksum routine for Internet Protocol family headers. |
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40 | * |
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41 | * This routine is very heavily used in the network |
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42 | * code and should be modified for each CPU to be as fast as possible. |
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43 | * |
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44 | * This implementation is the PowerPC version. |
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45 | * |
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46 | * $Id: in_cksum_powerpc.h,v 1.3 2008/08/18 21:16:42 joel Exp $ |
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47 | */ |
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48 | |
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49 | #define REDUCE1 sum = (sum & 0xffff) + (sum >> 16) |
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50 | /* Two REDUCE1s is faster than REDUCE1; if (sum > 65535) sum -= 65536; */ |
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51 | #define REDUCE { REDUCE1; REDUCE1; } |
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52 | |
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53 | int |
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54 | in_cksum(struct mbuf *m, int len) |
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55 | { |
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56 | uint8_t *w; |
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57 | int mlen = 0; |
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58 | int byte_swapped = 0; |
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59 | int n; |
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60 | u_int sum = 0; |
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61 | |
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62 | union { |
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63 | uint8_t c[2]; |
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64 | uint16_t s; |
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65 | } s_util; |
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66 | |
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67 | for (;m && len; m = m->m_next) { |
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68 | if (m->m_len == 0) |
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69 | continue; |
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70 | w = mtod(m, uint8_t *); |
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71 | |
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72 | if (mlen == -1) { |
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73 | /* |
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74 | * The first byte of this mbuf is the continuation |
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75 | * of a word spanning between this mbuf and the |
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76 | * last mbuf. |
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77 | * |
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78 | * s_util.c[0] is already saved when scanning previous |
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79 | * mbuf. |
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80 | */ |
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81 | s_util.c[1] = *w++; |
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82 | sum += s_util.s; |
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83 | mlen = m->m_len - 1; |
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84 | len--; |
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85 | } else { |
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86 | mlen = m->m_len; |
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87 | } |
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88 | if (len < mlen) |
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89 | mlen = len; |
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90 | len -= mlen; |
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91 | |
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92 | /* |
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93 | * Force to a word boundary. |
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94 | */ |
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95 | if ((3 & (long) w) && (mlen > 0)) { |
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96 | if ((1 & (long) w)) { |
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97 | REDUCE; |
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98 | sum <<= 8; |
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99 | s_util.c[0] = *w++; |
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100 | mlen--; |
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101 | byte_swapped = 1; |
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102 | } |
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103 | if ((2 & (long) w) && (mlen > 1)) { |
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104 | /* |
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105 | * Since the `sum' may contain full 32 bit |
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106 | * value, we can't simply add any value. |
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107 | */ |
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108 | __asm volatile( |
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109 | "lhz 7,0(%1);" /* load current data |
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110 | half word */ |
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111 | "addc %0,%0,7;" /* add to sum */ |
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112 | "addze %0,%0;" /* add carry bit */ |
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113 | : "+r"(sum) |
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114 | : "b"(w) |
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115 | : "7", "xer"); /* clobber r7, xer */ |
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116 | w += 2; |
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117 | mlen -= 2; |
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118 | } |
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119 | } |
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120 | |
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121 | if (mlen >= 64) { |
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122 | n = mlen >> 6; |
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123 | __asm volatile( |
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124 | "addic 0,0,0;" /* clear carry */ |
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125 | "mtctr %1;" /* load loop count */ |
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126 | "1:" |
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127 | "lwz 7,4(%2);" /* load current data |
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128 | word */ |
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129 | "lwz 8,8(%2);" |
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130 | "lwz 9,12(%2);" |
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131 | "lwz 10,16(%2);" |
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132 | "adde %0,%0,7;" /* add to sum */ |
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133 | "adde %0,%0,8;" |
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134 | "adde %0,%0,9;" |
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135 | "adde %0,%0,10;" |
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136 | "lwz 7,20(%2);" |
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137 | "lwz 8,24(%2);" |
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138 | "lwz 9,28(%2);" |
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139 | "lwz 10,32(%2);" |
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140 | "adde %0,%0,7;" |
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141 | "adde %0,%0,8;" |
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142 | "adde %0,%0,9;" |
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143 | "adde %0,%0,10;" |
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144 | "lwz 7,36(%2);" |
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145 | "lwz 8,40(%2);" |
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146 | "lwz 9,44(%2);" |
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147 | "lwz 10,48(%2);" |
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148 | "adde %0,%0,7;" |
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149 | "adde %0,%0,8;" |
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150 | "adde %0,%0,9;" |
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151 | "adde %0,%0,10;" |
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152 | "lwz 7,52(%2);" |
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153 | "lwz 8,56(%2);" |
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154 | "lwz 9,60(%2);" |
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155 | "lwzu 10,64(%2);" |
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156 | "adde %0,%0,7;" |
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157 | "adde %0,%0,8;" |
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158 | "adde %0,%0,9;" |
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159 | "adde %0,%0,10;" |
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160 | "bdnz 1b;" /* loop */ |
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161 | "addze %0,%0;" /* add carry bit */ |
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162 | : "+r"(sum) |
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163 | : "r"(n), "b"(w - 4) |
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164 | : "7", "8", "9", "10", "xer"); /* clobber r7, r8, r9, |
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165 | r10, xer */ |
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166 | w += n * 64; |
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167 | mlen -= n * 64; |
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168 | } |
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169 | |
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170 | if (mlen >= 8) { |
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171 | n = mlen >> 3; |
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172 | __asm volatile( |
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173 | "addic 0,0,0;" /* clear carry */ |
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174 | "mtctr %1;" /* load loop count */ |
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175 | "1:" |
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176 | "lwz 7,4(%2);" /* load current data |
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177 | word */ |
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178 | "lwzu 8,8(%2);" |
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179 | "adde %0,%0,7;" /* add to sum */ |
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180 | "adde %0,%0,8;" |
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181 | "bdnz 1b;" /* loop */ |
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182 | "addze %0,%0;" /* add carry bit */ |
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183 | : "+r"(sum) |
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184 | : "r"(n), "b"(w - 4) |
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185 | : "7", "8", "xer"); /* clobber r7, r8, xer */ |
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186 | w += n * 8; |
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187 | mlen -= n * 8; |
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188 | } |
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189 | |
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190 | if (mlen == 0 && byte_swapped == 0) |
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191 | continue; |
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192 | REDUCE; |
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193 | |
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194 | while ((mlen -= 2) >= 0) { |
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195 | sum += *(uint16_t *)w; |
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196 | w += 2; |
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197 | } |
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198 | |
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199 | if (byte_swapped) { |
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200 | REDUCE; |
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201 | sum <<= 8; |
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202 | byte_swapped = 0; |
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203 | if (mlen == -1) { |
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204 | s_util.c[1] = *w; |
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205 | sum += s_util.s; |
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206 | mlen = 0; |
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207 | } else |
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208 | mlen = -1; |
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209 | } else if (mlen == -1) |
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210 | s_util.c[0] = *w; |
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211 | } |
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212 | if (len) |
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213 | printf("cksum: out of data\n"); |
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214 | if (mlen == -1) { |
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215 | /* The last mbuf has odd # of bytes. Follow the |
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216 | standard (the odd byte may be shifted left by 8 bits |
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217 | or not as determined by endian-ness of the machine) */ |
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218 | s_util.c[1] = 0; |
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219 | sum += s_util.s; |
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220 | } |
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221 | REDUCE; |
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222 | return (~sum & 0xffff); |
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223 | } |
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