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2933 | svoboda | 1 | /* |
2 | * Copyright (c) 2008 Jiri Svoboda |
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3 | * All rights reserved. |
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4 | * |
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5 | * Redistribution and use in source and binary forms, with or without |
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6 | * modification, are permitted provided that the following conditions |
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7 | * are met: |
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8 | * |
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9 | * - Redistributions of source code must retain the above copyright |
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10 | * notice, 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 | * - The name of the author may not be used to endorse or promote products |
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15 | * derived from this software without specific prior written permission. |
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16 | * |
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17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
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18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
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19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
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20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
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21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
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22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
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23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
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24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
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25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
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26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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27 | */ |
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28 | |||
29 | /** @addtogroup rtld rtld |
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30 | * @brief |
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31 | * @{ |
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32 | */ |
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33 | /** |
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34 | * @file |
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35 | */ |
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36 | |||
3400 | svoboda | 37 | #include <loader/pcb.h> |
2965 | svoboda | 38 | #include <elf_dyn.h> |
39 | #include <rtld.h> |
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40 | |||
3400 | svoboda | 41 | void __main(pcb_t *pcb); |
42 | //void __io_init(void); |
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2952 | svoboda | 43 | void __exit(void); |
44 | |||
2933 | svoboda | 45 | static void kputint(unsigned i) |
46 | { |
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47 | unsigned dummy; |
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48 | asm volatile ( |
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3400 | svoboda | 49 | "movl $32, %%eax;" |
2933 | svoboda | 50 | "int $0x30" |
51 | : "=d" (dummy) /* output - %edx clobbered */ |
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52 | : "d" (i) /* input */ |
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53 | : "%eax","%ecx" /* all scratch registers clobbered */ |
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3400 | svoboda | 54 | ); |
2933 | svoboda | 55 | } |
56 | |||
3400 | svoboda | 57 | void __bootstrap(pcb_t *pcb) |
2933 | svoboda | 58 | { |
59 | unsigned bias; |
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60 | unsigned *got; |
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2965 | svoboda | 61 | elf_dyn_t *dynamic; |
62 | void *dptr; |
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2933 | svoboda | 63 | unsigned dval; |
64 | int i; |
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65 | |||
2965 | svoboda | 66 | size_t rel_entries; |
67 | size_t r_offset; |
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68 | elf_word r_info; |
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2933 | svoboda | 69 | unsigned rel_type; |
2965 | svoboda | 70 | elf_word sym_idx; |
71 | uintptr_t sym_addr; |
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2933 | svoboda | 72 | |
2965 | svoboda | 73 | elf_symbol_t *sym_table; |
74 | elf_rel_t *rel_table; |
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75 | elf_rel_t *jmp_rel_table; |
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76 | size_t jmp_rel_entries; |
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2933 | svoboda | 77 | |
3400 | svoboda | 78 | /* The program loader kindly provided us with these */ |
2989 | svoboda | 79 | dynamic = pcb->rtld_dynamic; |
80 | bias = pcb->rtld_bias; |
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81 | /* |
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2933 | svoboda | 82 | asm volatile ( |
2989 | svoboda | 83 | // Calculate the bias into %0 |
84 | // Generates "fake" R_386_RELATIVE run-time relocation |
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2933 | svoboda | 85 | " call .L0;" |
86 | ".L0: pop %0;" |
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87 | " subl $.L0, %0;" |
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88 | |||
2989 | svoboda | 89 | // Calculate run-time address of _DYNAMIC into %1 |
90 | // Generates "fake" R_386_RELATIVE run-time relocation |
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91 | " movl $_DYNAMIC, %1;" // Again, at link time 0-based VMA gets in |
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92 | " addl %0, %1;" // Add bias to compute run-time address |
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2933 | svoboda | 93 | |
94 | : "=r" (bias), "=r" (dynamic) |
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95 | ); |
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2989 | svoboda | 96 | */ |
3400 | svoboda | 97 | kputint(pcb); |
2933 | svoboda | 98 | kputint(bias); |
99 | kputint((unsigned)dynamic); |
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100 | |||
101 | /* parse DYNAMIC */ |
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102 | got = 0; |
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103 | sym_table = 0; |
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104 | rel_table = 0; |
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105 | rel_entries = 0; |
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2952 | svoboda | 106 | jmp_rel_table = 0; |
107 | jmp_rel_entries = 0; |
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2933 | svoboda | 108 | |
109 | i = 0; |
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110 | while (dynamic[i].d_tag != 0) { |
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2965 | svoboda | 111 | dptr = (void *)(dynamic[i].d_un.d_val + bias); |
2933 | svoboda | 112 | dval = dynamic[i].d_un.d_val; |
113 | |||
114 | switch (dynamic[i].d_tag) { |
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2966 | svoboda | 115 | case DT_PLTRELSZ: jmp_rel_entries = dval/8; break; |
116 | case DT_JMPREL: jmp_rel_table = dptr; break; |
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117 | case DT_PLTGOT: |
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2933 | svoboda | 118 | /* GOT address */ |
119 | got = dptr; break; |
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2966 | svoboda | 120 | case DT_SYMTAB: sym_table = dptr; break; |
121 | case DT_REL: rel_table = dptr; break; |
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122 | case DT_RELSZ: rel_entries = dval / 8; break; |
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2933 | svoboda | 123 | default: break; |
124 | } |
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125 | |||
126 | ++i; |
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127 | } |
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128 | |||
3400 | svoboda | 129 | // kputint(1); |
130 | // kputint((unsigned)sym_table); |
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131 | // kputint((unsigned)rel_table); |
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132 | // kputint((unsigned)rel_entries); |
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2933 | svoboda | 133 | |
134 | /* Now relocate all our dynsyms */ |
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3400 | svoboda | 135 | // kputint(-1); |
2933 | svoboda | 136 | |
137 | for (i=0; i<rel_entries; i++) { |
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138 | kputint(i); |
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139 | r_offset = rel_table[i].r_offset; |
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140 | r_info = rel_table[i].r_info; |
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141 | |||
142 | rel_type = ELF32_R_TYPE(r_info); |
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143 | |||
144 | kputint(rel_type); |
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145 | kputint(r_offset); |
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146 | |||
2952 | svoboda | 147 | switch (rel_type) { |
2966 | svoboda | 148 | case R_386_GLOB_DAT: |
149 | case R_386_JUMP_SLOT: |
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2933 | svoboda | 150 | kputint(16); |
151 | sym_idx = ELF32_R_SYM(r_info); |
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152 | |||
153 | sym_addr = sym_table[sym_idx].st_value + bias; |
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154 | kputint(sym_idx); |
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155 | kputint(sym_addr); |
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156 | |||
157 | *(unsigned *)(r_offset+bias) = sym_addr; |
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2952 | svoboda | 158 | break; |
159 | |||
2966 | svoboda | 160 | case R_386_32: |
2952 | svoboda | 161 | kputint(16); |
162 | sym_idx = ELF32_R_SYM(r_info); |
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163 | |||
164 | sym_addr = sym_table[sym_idx].st_value + bias; |
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165 | kputint(sym_idx); |
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166 | kputint(sym_addr); |
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167 | |||
168 | *(unsigned *)(r_offset+bias) += sym_addr; |
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169 | break; |
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170 | |||
2966 | svoboda | 171 | case R_386_RELATIVE: |
2952 | svoboda | 172 | kputint(16); |
173 | *(unsigned *)(r_offset+bias) += bias; |
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174 | break; |
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2933 | svoboda | 175 | } |
176 | } |
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177 | |||
178 | kputint(-1); |
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2952 | svoboda | 179 | |
180 | for (i=0; i<jmp_rel_entries; i++) { |
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181 | kputint(i); |
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182 | r_offset = jmp_rel_table[i].r_offset; |
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183 | r_info = jmp_rel_table[i].r_info; |
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2933 | svoboda | 184 | |
2952 | svoboda | 185 | rel_type = ELF32_R_TYPE(r_info); |
2933 | svoboda | 186 | |
2952 | svoboda | 187 | kputint(rel_type); |
188 | kputint(r_offset); |
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189 | |||
190 | switch (rel_type) { |
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2966 | svoboda | 191 | case R_386_GLOB_DAT: |
192 | case R_386_JUMP_SLOT: |
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2952 | svoboda | 193 | kputint(16); |
194 | sym_idx = ELF32_R_SYM(r_info); |
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195 | |||
196 | sym_addr = sym_table[sym_idx].st_value + bias; |
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197 | kputint(sym_idx); |
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198 | kputint(sym_addr); |
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199 | |||
200 | *(unsigned *)(r_offset+bias) = sym_addr; |
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201 | break; |
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202 | |||
2966 | svoboda | 203 | case R_386_32: |
2952 | svoboda | 204 | kputint(16); |
205 | sym_idx = ELF32_R_SYM(r_info); |
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206 | |||
207 | sym_addr = sym_table[sym_idx].st_value + bias; |
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208 | kputint(sym_idx); |
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209 | kputint(sym_addr); |
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210 | |||
211 | *(unsigned *)(r_offset+bias) += sym_addr; |
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212 | break; |
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213 | |||
2966 | svoboda | 214 | case R_386_RELATIVE: |
2952 | svoboda | 215 | kputint(16); |
216 | *(unsigned *)(r_offset+bias) += bias; |
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217 | break; |
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218 | } |
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219 | } |
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220 | |||
221 | kputint(-1); |
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3400 | svoboda | 222 | kputint(0x42); |
2981 | svoboda | 223 | |
224 | /* This will come in handy */ |
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3400 | svoboda | 225 | __pcb = pcb; |
2981 | svoboda | 226 | runtime_env.rtld_dynamic = dynamic; |
227 | runtime_env.rtld.bias = bias; |
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3400 | svoboda | 228 | |
229 | kputint(0x43); |
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2952 | svoboda | 230 | |
231 | /* Init libc and run rtld main */ |
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3400 | svoboda | 232 | __main(pcb); |
2952 | svoboda | 233 | |
3400 | svoboda | 234 | kputint(0x44); |
235 | |||
236 | // kputint(33); |
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237 | // __io_init(); |
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2952 | svoboda | 238 | kputint(34); |
2933 | svoboda | 239 | _rtld_main(); |
2952 | svoboda | 240 | kputint(35); |
241 | __exit(); |
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2933 | svoboda | 242 | |
2952 | svoboda | 243 | kputint(36); |
244 | |||
2933 | svoboda | 245 | asm ( |
246 | "movl $250, %%eax;" |
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247 | "int $0x30" |
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248 | : /* output */ |
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249 | : /* input */ |
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250 | : "%eax","%ecx","%edx" /* all scratch registers clobbered */ |
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251 | ); |
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252 | } |
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253 | |||
254 | /** @} |
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255 | */ |