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1 #ifndef CYGONCE_KERNEL_LOTTERY_HXX |
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2 #define CYGONCE_KERNEL_LOTTERY_HXX |
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3 |
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4 //========================================================================== |
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5 // |
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6 // lottery.hxx |
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7 // |
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8 // Lottery scheduler class declarations |
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9 // |
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10 //========================================================================== |
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11 //####COPYRIGHTBEGIN#### |
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12 // |
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13 // ------------------------------------------- |
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14 // The contents of this file are subject to the Cygnus eCos Public License |
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15 // Version 1.0 (the "License"); you may not use this file except in |
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16 // compliance with the License. You may obtain a copy of the License at |
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17 // http://sourceware.cygnus.com/ecos |
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18 // |
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19 // Software distributed under the License is distributed on an "AS IS" |
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20 // basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See the |
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21 // License for the specific language governing rights and limitations under |
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22 // the License. |
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23 // |
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24 // The Original Code is eCos - Embedded Cygnus Operating System, released |
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25 // September 30, 1998. |
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26 // |
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27 // The Initial Developer of the Original Code is Cygnus. Portions created |
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28 // by Cygnus are Copyright (C) 1998 Cygnus Solutions. All Rights Reserved. |
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29 // ------------------------------------------- |
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30 // |
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31 //####COPYRIGHTEND#### |
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32 //========================================================================== |
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33 //#####DESCRIPTIONBEGIN#### |
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34 // |
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35 // Author(s): nickg |
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36 // Contributors: nickg |
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37 // Date: 1997-09-10 |
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38 // Purpose: Define lottery scheduler implementation |
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39 // Description: The classes defined here are used as base classes |
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40 // by the common classes that define schedulers and thread |
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41 // things. A lottery scheduler provides each thread with a |
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42 // share of the processor based on the number of tickets that |
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43 // it owns. |
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44 // Usage: Included according to configuration by |
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45 // <cyg/kernel/sched.hxx> |
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46 // |
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47 //####DESCRIPTIONEND#### |
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48 // |
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49 //========================================================================== |
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50 |
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51 #include <cyg/kernel/ktypes.h> |
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52 |
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53 // ------------------------------------------------------------------------- |
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54 // Customize the scheduler |
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55 |
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56 #define CYGIMP_THREAD_PRIORITY 1 // Threads have changable priorities |
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57 |
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58 #define CYG_THREAD_MIN_PRIORITY 1 |
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59 #define CYG_THREAD_MAX_PRIORITY 0x7FFFFFFF |
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60 |
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61 // set default scheduling info value for thread constructors. |
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62 #define CYG_SCHED_DEFAULT_INFO CYG_THREAD_MAX_PRIORITY |
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63 |
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64 #error Lottery Scheduler not yet complete, do not use!!! |
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65 |
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66 // ------------------------------------------------------------------------- |
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67 // Thread queue implementation. |
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68 // This class provides the (scheduler specific) implementation of the |
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69 // thread queue class. |
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70 |
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71 class Cyg_ThreadQueue_Implementation |
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72 { |
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73 friend class Cyg_Scheduler_Implementation; |
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74 friend class Cyg_SchedThread_Implementation; |
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75 |
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76 Cyg_Thread *queue; |
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77 |
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78 protected: |
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79 |
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80 // API used by Cyg_ThreadQueue |
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81 |
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82 // Add thread to queue |
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83 void enqueue(Cyg_Thread *thread); |
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84 |
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85 // return first thread on queue |
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86 Cyg_Thread *highpri(); |
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87 |
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88 // remove first thread on queue |
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89 Cyg_Thread *dequeue(); |
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90 |
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91 // remove specified thread from queue |
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92 void remove(Cyg_Thread *thread); |
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93 |
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94 // test if queue is empty |
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95 cyg_bool empty(); |
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96 |
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97 void rotate(); // Rotate the queue |
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98 }; |
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99 |
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100 inline cyg_bool Cyg_ThreadQueue_Implementation::empty() |
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101 { |
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102 return queue == NULL; |
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103 } |
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104 |
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105 // ------------------------------------------------------------------------- |
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106 // This class contains the implementation details of the scheduler, and |
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107 // provides a standard API for accessing it. |
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108 |
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109 class Cyg_Scheduler_Implementation |
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110 : public Cyg_Scheduler_Base |
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111 { |
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112 friend class Cyg_ThreadQueue_Implementation; |
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113 friend class Cyg_SchedThread_Implementation; |
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114 |
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115 // All runnable threads are kept on a single run queue |
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116 // in MRU order. |
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117 Cyg_ThreadQueue_Implementation run_queue; |
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118 |
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119 cyg_uint32 rand_seed; |
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120 |
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121 cyg_int32 total_tickets; |
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122 |
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123 protected: |
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124 |
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125 Cyg_Scheduler_Implementation(); // Constructor |
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126 |
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127 // The following functions provide the scheduler implementation |
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128 // interface to the Cyg_Scheduler class. These are protected |
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129 // so that only the scheduler can call them. |
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130 |
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131 // choose a new thread |
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132 Cyg_Thread *schedule(); |
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133 |
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134 // make thread schedulable |
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135 void add_thread(Cyg_Thread *thread); |
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136 |
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137 // make thread un-schedulable |
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138 void rem_thread(Cyg_Thread *thread); |
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139 |
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140 // register thread with scheduler |
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141 void register_thread(Cyg_Thread *thread); |
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142 |
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143 // deregister thread |
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144 void deregister_thread(Cyg_Thread *thread); |
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145 |
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146 // Test the given priority for uniqueness |
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147 cyg_bool unique( cyg_priority priority); |
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148 |
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149 #ifdef CYGSEM_KERNEL_SCHED_TIMESLICE |
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150 |
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151 // If timeslicing is enbled, define a scheduler |
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152 // entry point to do timeslicing. This will be |
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153 // called from the RTC DSR. |
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154 |
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155 protected: |
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156 |
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157 static cyg_count32 timeslice_count; |
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158 |
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159 public: |
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160 void timeslice(); |
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161 |
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162 static void reset_timeslice_count(); |
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163 |
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164 #endif |
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165 |
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166 |
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167 }; |
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168 |
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169 // ------------------------------------------------------------------------- |
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170 // Cyg_Scheduler_Implementation inlines |
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171 |
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172 #ifdef CYGSEM_KERNEL_SCHED_TIMESLICE |
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173 |
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174 inline void Cyg_Scheduler_Implementation::reset_timeslice_count() |
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175 { |
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176 timeslice_count = CYGNUM_KERNEL_SCHED_TIMESLICE_TICKS; |
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177 } |
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178 |
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179 #endif |
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180 |
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181 // ------------------------------------------------------------------------- |
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182 // Scheduler thread implementation. |
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183 // This class provides the implementation of the scheduler specific parts |
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184 // of each thread. |
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185 |
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186 class Cyg_SchedThread_Implementation |
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187 { |
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188 friend class Cyg_Scheduler_Implementation; |
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189 friend class Cyg_ThreadQueue_Implementation; |
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190 |
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191 Cyg_Thread *next; // next thread in queue |
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192 Cyg_Thread *prev; // previous thread in queue |
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193 |
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194 void insert( Cyg_Thread *thread ); // Insert thread in front of this |
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195 |
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196 void remove(); // remove this from queue |
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197 |
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198 protected: |
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199 |
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200 cyg_priority priority; // current thread priority == tickets held |
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201 |
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202 cyg_priority compensation_tickets; // sleep compensation |
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203 |
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204 Cyg_SchedThread_Implementation(CYG_ADDRWORD sched_info); |
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205 |
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206 void yield(); // Yield CPU to next thread |
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207 |
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208 }; |
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209 |
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210 // ------------------------------------------------------------------------- |
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211 #endif // ifndef CYGONCE_KERNEL_LOTTERY_HXX |
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212 // EOF lottery.hxx |
