1 | /* |
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2 | * Heap Handler |
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3 | * |
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4 | * COPYRIGHT (c) 1989-1998. |
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5 | * On-Line Applications Research Corporation (OAR). |
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6 | * Copyright assigned to U.S. Government, 1994. |
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7 | * |
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8 | * The license and distribution terms for this file may be |
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9 | * found in the file LICENSE in this distribution or at |
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10 | * http://www.OARcorp.com/rtems/license.html. |
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11 | * |
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12 | * $Id$ |
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13 | */ |
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14 | |
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15 | |
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16 | #include <rtems/system.h> |
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17 | #include <rtems/score/sysstate.h> |
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18 | #include <rtems/score/heap.h> |
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19 | |
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20 | /*PAGE |
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21 | * |
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22 | * _Heap_Initialize |
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23 | * |
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24 | * This kernel routine initializes a heap. |
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25 | * |
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26 | * Input parameters: |
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27 | * the_heap - pointer to heap header |
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28 | * starting_address - starting address of heap |
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29 | * size - size of heap |
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30 | * page_size - allocatable unit of memory |
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31 | * |
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32 | * Output parameters: |
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33 | * returns - maximum memory available if RTEMS_SUCCESSFUL |
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34 | * 0 - otherwise |
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35 | * |
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36 | * This is what a heap looks like in memory immediately |
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37 | * after initialization: |
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38 | * |
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39 | * +--------------------------------+ |
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40 | * 0 | size = 0 | status = used | a.k.a. dummy back flag |
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41 | * +--------------------------------+ |
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42 | * 4 | size = size-8 | status = free | a.k.a. front flag |
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43 | * +--------------------------------+ |
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44 | * 8 | next = PERM HEAP_TAIL | |
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45 | * +--------------------------------+ |
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46 | * 12 | previous = PERM HEAP_HEAD | |
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47 | * +--------------------------------+ |
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48 | * | | |
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49 | * | memory available | |
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50 | * | for allocation | |
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51 | * | | |
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52 | * +--------------------------------+ |
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53 | * size - 8 | size = size-8 | status = free | a.k.a. back flag |
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54 | * +--------------------------------+ |
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55 | * size - 4 | size = 0 | status = used | a.k.a. dummy front flag |
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56 | * +--------------------------------+ |
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57 | */ |
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58 | |
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59 | unsigned32 _Heap_Initialize( |
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60 | Heap_Control *the_heap, |
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61 | void *starting_address, |
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62 | unsigned32 size, |
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63 | unsigned32 page_size |
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64 | ) |
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65 | { |
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66 | Heap_Block *the_block; |
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67 | unsigned32 the_size; |
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68 | |
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69 | if ( !_Heap_Is_page_size_valid( page_size ) || |
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70 | (size < HEAP_MINIMUM_SIZE) ) |
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71 | return 0; |
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72 | |
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73 | the_heap->page_size = page_size; |
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74 | the_size = size - HEAP_OVERHEAD; |
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75 | |
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76 | the_block = (Heap_Block *) starting_address; |
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77 | the_block->back_flag = HEAP_DUMMY_FLAG; |
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78 | the_block->front_flag = the_size; |
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79 | the_block->next = _Heap_Tail( the_heap ); |
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80 | the_block->previous = _Heap_Head( the_heap ); |
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81 | |
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82 | the_heap->start = the_block; |
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83 | the_heap->first = the_block; |
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84 | the_heap->permanent_null = NULL; |
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85 | the_heap->last = the_block; |
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86 | |
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87 | the_block = _Heap_Next_block( the_block ); |
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88 | the_block->back_flag = the_size; |
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89 | the_block->front_flag = HEAP_DUMMY_FLAG; |
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90 | the_heap->final = the_block; |
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91 | |
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92 | return ( the_size - HEAP_BLOCK_USED_OVERHEAD ); |
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93 | } |
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94 | |
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95 | /*PAGE |
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96 | * |
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97 | * _Heap_Extend |
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98 | * |
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99 | * This routine grows the_heap memory area using the size bytes which |
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100 | * begin at starting_address. |
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101 | * |
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102 | * Input parameters: |
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103 | * the_heap - pointer to heap header. |
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104 | * starting_address - pointer to the memory area. |
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105 | * size - size in bytes of the memory block to allocate. |
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106 | * |
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107 | * Output parameters: |
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108 | * *amount_extended - amount of memory added to the_heap |
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109 | */ |
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110 | |
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111 | Heap_Extend_status _Heap_Extend( |
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112 | Heap_Control *the_heap, |
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113 | void *starting_address, |
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114 | unsigned32 size, |
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115 | unsigned32 *amount_extended |
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116 | ) |
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117 | { |
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118 | Heap_Block *the_block; |
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119 | unsigned32 *p; |
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120 | |
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121 | /* |
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122 | * The overhead was taken from the original heap memory. |
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123 | */ |
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124 | |
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125 | Heap_Block *old_final; |
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126 | Heap_Block *new_final; |
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127 | |
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128 | /* |
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129 | * There are five possibilities for the location of starting |
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130 | * address: |
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131 | * |
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132 | * 1. non-contiguous lower address (NOT SUPPORTED) |
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133 | * 2. contiguous lower address (NOT SUPPORTED) |
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134 | * 3. in the heap (ERROR) |
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135 | * 4. contiguous higher address (SUPPORTED) |
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136 | * 5. non-contiguous higher address (NOT SUPPORTED) |
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137 | * |
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138 | * As noted, this code only supports (4). |
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139 | */ |
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140 | |
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141 | if ( starting_address >= (void *) the_heap->start && /* case 3 */ |
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142 | starting_address <= (void *) the_heap->final |
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143 | ) |
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144 | return HEAP_EXTEND_ERROR; |
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145 | |
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146 | if ( starting_address < (void *) the_heap->start ) { /* cases 1 and 2 */ |
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147 | |
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148 | return HEAP_EXTEND_NOT_IMPLEMENTED; /* cases 1 and 2 */ |
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149 | |
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150 | } else { /* cases 4 and 5 */ |
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151 | |
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152 | the_block = (Heap_Block *) |
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153 | _Addresses_Subtract_offset( starting_address, HEAP_OVERHEAD ); |
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154 | if ( the_block != the_heap->final ) |
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155 | return HEAP_EXTEND_NOT_IMPLEMENTED; /* case 5 */ |
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156 | } |
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157 | |
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158 | /* |
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159 | * Currently only case 4 should make it to this point. |
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160 | * The basic trick is to make the extend area look like a used |
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161 | * block and free it. |
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162 | */ |
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163 | |
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164 | *amount_extended = size; |
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165 | |
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166 | old_final = the_heap->final; |
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167 | new_final = _Addresses_Add_offset( old_final, size ); |
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168 | /* SAME AS: _Addresses_Add_offset( starting_address, size-HEAP_OVERHEAD ); */ |
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169 | |
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170 | the_heap->final = new_final; |
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171 | |
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172 | old_final->front_flag = |
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173 | new_final->back_flag = _Heap_Build_flag( size, HEAP_BLOCK_USED ); |
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174 | new_final->front_flag = HEAP_DUMMY_FLAG; |
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175 | |
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176 | /* |
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177 | * Must pass in address of "user" area |
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178 | * So add in the offset field. |
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179 | */ |
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180 | |
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181 | p = (unsigned32 *) &old_final->next; |
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182 | *p = sizeof(unsigned32); |
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183 | p++; |
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184 | _Heap_Free( the_heap, p ); |
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185 | |
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186 | return HEAP_EXTEND_SUCCESSFUL; |
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187 | } |
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188 | |
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189 | /*PAGE |
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190 | * |
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191 | * _Heap_Allocate |
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192 | * |
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193 | * This kernel routine allocates the requested size of memory |
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194 | * from the specified heap. |
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195 | * |
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196 | * Input parameters: |
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197 | * the_heap - pointer to heap header. |
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198 | * size - size in bytes of the memory block to allocate. |
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199 | * |
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200 | * Output parameters: |
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201 | * returns - starting address of memory block allocated |
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202 | */ |
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203 | |
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204 | void *_Heap_Allocate( |
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205 | Heap_Control *the_heap, |
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206 | unsigned32 size |
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207 | ) |
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208 | { |
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209 | unsigned32 excess; |
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210 | unsigned32 the_size; |
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211 | Heap_Block *the_block; |
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212 | Heap_Block *next_block; |
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213 | Heap_Block *temporary_block; |
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214 | void *ptr; |
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215 | unsigned32 offset; |
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216 | |
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217 | excess = size % the_heap->page_size; |
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218 | the_size = size + the_heap->page_size + HEAP_BLOCK_USED_OVERHEAD; |
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219 | |
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220 | if ( excess ) |
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221 | the_size += the_heap->page_size - excess; |
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222 | |
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223 | if ( the_size < sizeof( Heap_Block ) ) |
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224 | the_size = sizeof( Heap_Block ); |
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225 | |
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226 | for ( the_block = the_heap->first; |
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227 | ; |
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228 | the_block = the_block->next ) { |
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229 | if ( the_block == _Heap_Tail( the_heap ) ) |
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230 | return( NULL ); |
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231 | if ( the_block->front_flag >= the_size ) |
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232 | break; |
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233 | } |
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234 | |
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235 | if ( (the_block->front_flag - the_size) > |
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236 | (the_heap->page_size + HEAP_BLOCK_USED_OVERHEAD) ) { |
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237 | the_block->front_flag -= the_size; |
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238 | next_block = _Heap_Next_block( the_block ); |
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239 | next_block->back_flag = the_block->front_flag; |
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240 | |
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241 | temporary_block = _Heap_Block_at( next_block, the_size ); |
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242 | temporary_block->back_flag = |
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243 | next_block->front_flag = _Heap_Build_flag( the_size, |
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244 | HEAP_BLOCK_USED ); |
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245 | ptr = _Heap_Start_of_user_area( next_block ); |
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246 | } else { |
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247 | next_block = _Heap_Next_block( the_block ); |
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248 | next_block->back_flag = _Heap_Build_flag( the_block->front_flag, |
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249 | HEAP_BLOCK_USED ); |
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250 | the_block->front_flag = next_block->back_flag; |
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251 | the_block->next->previous = the_block->previous; |
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252 | the_block->previous->next = the_block->next; |
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253 | ptr = _Heap_Start_of_user_area( the_block ); |
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254 | } |
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255 | |
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256 | /* |
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257 | * round ptr up to a multiple of page size |
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258 | * Have to save the bump amount in the buffer so that free can figure it out |
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259 | */ |
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260 | |
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261 | offset = the_heap->page_size - (((unsigned32) ptr) & (the_heap->page_size - 1)); |
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262 | ptr = _Addresses_Add_offset( ptr, offset ); |
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263 | *(((unsigned32 *) ptr) - 1) = offset; |
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264 | |
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265 | #ifdef RTEMS_DEBUG |
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266 | { |
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267 | unsigned32 ptr_u32; |
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268 | ptr_u32 = (unsigned32) ptr; |
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269 | if (ptr_u32 & (the_heap->page_size - 1)) |
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270 | abort(); |
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271 | } |
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272 | #endif |
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273 | |
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274 | return ptr; |
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275 | } |
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276 | |
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277 | /*PAGE |
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278 | * |
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279 | * _Heap_Size_of_user_area |
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280 | * |
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281 | * This kernel routine returns the size of the memory area |
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282 | * given heap block. |
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283 | * |
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284 | * Input parameters: |
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285 | * the_heap - pointer to heap header |
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286 | * starting_address - starting address of the memory block to free. |
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287 | * size - pointer to size of area |
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288 | * |
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289 | * Output parameters: |
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290 | * size - size of area filled in |
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291 | * TRUE - if starting_address is valid heap address |
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292 | * FALSE - if starting_address is invalid heap address |
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293 | */ |
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294 | |
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295 | boolean _Heap_Size_of_user_area( |
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296 | Heap_Control *the_heap, |
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297 | void *starting_address, |
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298 | unsigned32 *size |
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299 | ) |
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300 | { |
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301 | Heap_Block *the_block; |
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302 | Heap_Block *next_block; |
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303 | unsigned32 the_size; |
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304 | |
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305 | the_block = _Heap_User_block_at( starting_address ); |
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306 | |
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307 | if ( !_Heap_Is_block_in( the_heap, the_block ) || |
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308 | _Heap_Is_block_free( the_block ) ) |
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309 | return( FALSE ); |
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310 | |
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311 | the_size = _Heap_Block_size( the_block ); |
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312 | next_block = _Heap_Block_at( the_block, the_size ); |
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313 | |
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314 | if ( !_Heap_Is_block_in( the_heap, next_block ) || |
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315 | (the_block->front_flag != next_block->back_flag) ) |
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316 | return( FALSE ); |
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317 | |
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318 | *size = the_size; |
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319 | return( TRUE ); |
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320 | } |
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321 | |
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322 | /*PAGE |
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323 | * |
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324 | * _Heap_Free |
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325 | * |
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326 | * This kernel routine returns the memory designated by the |
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327 | * given heap and given starting address to the memory pool. |
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328 | * |
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329 | * Input parameters: |
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330 | * the_heap - pointer to heap header |
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331 | * starting_address - starting address of the memory block to free. |
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332 | * |
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333 | * Output parameters: |
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334 | * TRUE - if starting_address is valid heap address |
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335 | * FALSE - if starting_address is invalid heap address |
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336 | */ |
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337 | |
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338 | boolean _Heap_Free( |
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339 | Heap_Control *the_heap, |
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340 | void *starting_address |
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341 | ) |
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342 | { |
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343 | Heap_Block *the_block; |
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344 | Heap_Block *next_block; |
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345 | Heap_Block *new_next_block; |
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346 | Heap_Block *previous_block; |
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347 | Heap_Block *temporary_block; |
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348 | unsigned32 the_size; |
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349 | |
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350 | the_block = _Heap_User_block_at( starting_address ); |
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351 | |
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352 | if ( !_Heap_Is_block_in( the_heap, the_block ) || |
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353 | _Heap_Is_block_free( the_block ) ) { |
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354 | return( FALSE ); |
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355 | } |
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356 | |
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357 | the_size = _Heap_Block_size( the_block ); |
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358 | next_block = _Heap_Block_at( the_block, the_size ); |
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359 | |
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360 | if ( !_Heap_Is_block_in( the_heap, next_block ) || |
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361 | (the_block->front_flag != next_block->back_flag) ) { |
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362 | return( FALSE ); |
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363 | } |
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364 | |
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365 | if ( _Heap_Is_previous_block_free( the_block ) ) { |
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366 | previous_block = _Heap_Previous_block( the_block ); |
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367 | |
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368 | if ( !_Heap_Is_block_in( the_heap, previous_block ) ) { |
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369 | return( FALSE ); |
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370 | } |
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371 | |
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372 | if ( _Heap_Is_block_free( next_block ) ) { /* coalesce both */ |
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373 | previous_block->front_flag += next_block->front_flag + the_size; |
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374 | temporary_block = _Heap_Next_block( previous_block ); |
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375 | temporary_block->back_flag = previous_block->front_flag; |
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376 | next_block->next->previous = next_block->previous; |
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377 | next_block->previous->next = next_block->next; |
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378 | } |
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379 | else { /* coalesce prev */ |
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380 | previous_block->front_flag = |
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381 | next_block->back_flag = previous_block->front_flag + the_size; |
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382 | } |
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383 | } |
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384 | else if ( _Heap_Is_block_free( next_block ) ) { /* coalesce next */ |
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385 | the_block->front_flag = the_size + next_block->front_flag; |
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386 | new_next_block = _Heap_Next_block( the_block ); |
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387 | new_next_block->back_flag = the_block->front_flag; |
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388 | the_block->next = next_block->next; |
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389 | the_block->previous = next_block->previous; |
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390 | next_block->previous->next = the_block; |
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391 | next_block->next->previous = the_block; |
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392 | |
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393 | if (the_heap->first == next_block) |
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394 | the_heap->first = the_block; |
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395 | } |
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396 | else { /* no coalesce */ |
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397 | next_block->back_flag = |
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398 | the_block->front_flag = the_size; |
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399 | the_block->previous = _Heap_Head( the_heap ); |
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400 | the_block->next = the_heap->first; |
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401 | the_heap->first = the_block; |
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402 | the_block->next->previous = the_block; |
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403 | } |
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404 | |
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405 | return( TRUE ); |
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406 | } |
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407 | |
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408 | /*PAGE |
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409 | * |
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410 | * _Heap_Walk |
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411 | * |
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412 | * This kernel routine walks the heap and verifies its correctness. |
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413 | * |
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414 | * Input parameters: |
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415 | * the_heap - pointer to heap header |
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416 | * source - a numeric indicator of the invoker of this routine |
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417 | * do_dump - when TRUE print the information |
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418 | * |
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419 | * Output parameters: NONE |
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420 | */ |
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421 | |
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422 | #ifndef RTEMS_DEBUG |
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423 | |
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424 | void _Heap_Walk( |
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425 | Heap_Control *the_heap, |
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426 | int source, |
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427 | boolean do_dump |
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428 | ) |
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429 | { |
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430 | } |
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431 | |
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432 | #else |
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433 | |
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434 | #include <stdio.h> |
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435 | #include <unistd.h> |
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436 | |
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437 | void _Heap_Walk( |
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438 | Heap_Control *the_heap, |
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439 | int source, |
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440 | boolean do_dump |
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441 | ) |
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442 | { |
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443 | Heap_Block *the_block = 0; /* avoid warnings */ |
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444 | Heap_Block *next_block = 0; /* avoid warnings */ |
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445 | int notdone = 1; |
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446 | int error = 0; |
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447 | int passes = 0; |
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448 | |
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449 | /* |
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450 | * We don't want to allow walking the heap until we have |
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451 | * transferred control to the user task so we watch the |
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452 | * system state. |
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453 | */ |
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454 | |
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455 | if ( !_System_state_Is_up( _System_state_Get() ) ) |
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456 | return; |
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457 | |
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458 | the_block = the_heap->start; |
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459 | |
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460 | if (do_dump == TRUE) { |
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461 | printf("\nPASS: %d start @ 0x%p final 0x%p, first 0x%p last 0x%p\n", |
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462 | source, the_heap->start, the_heap->final, |
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463 | the_heap->first, the_heap->last |
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464 | ); |
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465 | } |
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466 | |
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467 | /* |
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468 | * Handle the 1st block |
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469 | */ |
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470 | |
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471 | if (the_block->back_flag != HEAP_DUMMY_FLAG) { |
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472 | printf("PASS: %d Back flag of 1st block isn't HEAP_DUMMY_FLAG\n", source); |
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473 | error = 1; |
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474 | } |
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475 | |
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476 | while (notdone) { |
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477 | passes++; |
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478 | if (error && (passes > 10)) |
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479 | abort(); |
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480 | |
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481 | if (do_dump == TRUE) { |
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482 | printf("PASS: %d Block @ 0x%p Back %d, Front %d", |
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483 | source, the_block, |
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484 | the_block->back_flag, the_block->front_flag); |
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485 | if ( _Heap_Is_block_free(the_block) ) { |
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486 | printf( " Prev 0x%p, Next 0x%p\n", |
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487 | the_block->previous, the_block->next); |
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488 | } else { |
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489 | printf("\n"); |
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490 | } |
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491 | } |
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492 | |
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493 | /* |
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494 | * Handle the last block |
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495 | */ |
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496 | |
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497 | if ( the_block->front_flag != HEAP_DUMMY_FLAG ) { |
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498 | next_block = _Heap_Next_block(the_block); |
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499 | if ( the_block->front_flag != next_block->back_flag ) { |
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500 | error = 1; |
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501 | printf("PASS: %d Front and back flags don't match\n", source); |
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502 | printf(" Current Block (%p): Back - %d, Front - %d", |
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503 | the_block, the_block->back_flag, the_block->front_flag); |
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504 | if (do_dump == TRUE) { |
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505 | if (_Heap_Is_block_free(the_block)) { |
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506 | printf(" Prev 0x%p, Next 0x%p\n", |
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507 | the_block->previous, the_block->next); |
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508 | } else { |
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509 | printf("\n"); |
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510 | } |
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511 | } else { |
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512 | printf("\n"); |
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513 | } |
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514 | printf(" Next Block (%p): Back - %d, Front - %d", |
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515 | next_block, next_block->back_flag, next_block->front_flag); |
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516 | if (do_dump == TRUE) { |
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517 | if (_Heap_Is_block_free(next_block)) { |
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518 | printf(" Prev 0x%p, Next 0x%p\n", |
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519 | the_block->previous, the_block->next); |
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520 | } else { |
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521 | printf("\n"); |
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522 | } |
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523 | } else { |
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524 | printf("\n"); |
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525 | } |
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526 | } |
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527 | } |
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528 | |
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529 | if (the_block->front_flag == HEAP_DUMMY_FLAG) |
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530 | notdone = 0; |
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531 | else |
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532 | the_block = next_block; |
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533 | } |
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534 | |
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535 | if (error) |
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536 | abort(); |
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537 | } |
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538 | #endif |
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