1 | /*
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2 | * Copyright (c) 2004-2005, Swedish Institute of Computer Science.
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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 | * 1. Redistributions of source code must retain the above copyright
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9 | * notice, this list of conditions and the following disclaimer.
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10 | * 2. Redistributions in binary form must reproduce the above copyright
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11 | * notice, this list of conditions and the following disclaimer in the
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12 | * documentation and/or other materials provided with the distribution.
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13 | * 3. Neither the name of the Institute nor the names of its contributors
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14 | * may be used to endorse or promote products derived from this software
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15 | * without specific prior written permission.
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16 | *
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17 | * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
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18 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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19 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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20 | * ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
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21 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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22 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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23 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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24 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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25 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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26 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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27 | * SUCH DAMAGE.
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28 | *
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29 | * This file is part of the uIP TCP/IP stack
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30 | *
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31 | * Author: Adam Dunkels <adam@sics.se>
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32 | *
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33 | * $Id: pt.h 158 2016-02-20 13:43:32Z coas-nagasima $
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34 | */
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35 |
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36 | /**
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37 | * \addtogroup pt
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38 | * @{
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39 | */
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40 |
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41 | /**
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42 | * \file
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43 | * Protothreads implementation.
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44 | * \author
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45 | * Adam Dunkels <adam@sics.se>
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46 | *
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47 | */
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48 |
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49 | #ifndef __PT_H__
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50 | #define __PT_H__
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51 |
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52 | #include "sys/lc.h"
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53 |
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54 | struct pt {
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55 | lc_t lc;
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56 | };
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57 |
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58 | #define PT_WAITING 0
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59 | #define PT_EXITED 1
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60 | #define PT_ENDED 2
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61 | #define PT_YIELDED 3
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62 |
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63 | /**
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64 | * \name Initialization
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65 | * @{
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66 | */
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67 |
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68 | /**
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69 | * Initialize a protothread.
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70 | *
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71 | * Initializes a protothread. Initialization must be done prior to
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72 | * starting to execute the protothread.
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73 | *
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74 | * \param pt A pointer to the protothread control structure.
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75 | *
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76 | * \sa PT_SPAWN()
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77 | *
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78 | * \hideinitializer
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79 | */
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80 | #define PT_INIT(pt) LC_INIT((pt)->lc)
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81 |
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82 | /** @} */
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83 |
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84 | /**
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85 | * \name Declaration and definition
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86 | * @{
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87 | */
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88 |
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89 | /**
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90 | * Declaration of a protothread.
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91 | *
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92 | * This macro is used to declare a protothread. All protothreads must
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93 | * be declared with this macro.
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94 | *
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95 | * \param name_args The name and arguments of the C function
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96 | * implementing the protothread.
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97 | *
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98 | * \hideinitializer
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99 | */
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100 | #define PT_THREAD(name_args) char name_args
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101 |
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102 | /**
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103 | * Declare the start of a protothread inside the C function
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104 | * implementing the protothread.
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105 | *
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106 | * This macro is used to declare the starting point of a
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107 | * protothread. It should be placed at the start of the function in
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108 | * which the protothread runs. All C statements above the PT_BEGIN()
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109 | * invokation will be executed each time the protothread is scheduled.
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110 | *
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111 | * \param pt A pointer to the protothread control structure.
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112 | *
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113 | * \hideinitializer
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114 | */
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115 | #define PT_BEGIN(pt) { char PT_YIELD_FLAG = 1; LC_RESUME((pt)->lc)
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116 |
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117 | /**
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118 | * Declare the end of a protothread.
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119 | *
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120 | * This macro is used for declaring that a protothread ends. It must
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121 | * always be used together with a matching PT_BEGIN() macro.
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122 | *
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123 | * \param pt A pointer to the protothread control structure.
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124 | *
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125 | * \hideinitializer
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126 | */
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127 | #define PT_END(pt) LC_END((pt)->lc); PT_YIELD_FLAG = 0; \
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128 | PT_INIT(pt); return PT_ENDED; }
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129 |
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130 | /** @} */
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131 |
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132 | /**
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133 | * \name Blocked wait
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134 | * @{
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135 | */
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136 |
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137 | /**
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138 | * Block and wait until condition is true.
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139 | *
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140 | * This macro blocks the protothread until the specified condition is
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141 | * true.
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142 | *
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143 | * \param pt A pointer to the protothread control structure.
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144 | * \param condition The condition.
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145 | *
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146 | * \hideinitializer
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147 | */
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148 | #define PT_WAIT_UNTIL(pt, condition) \
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149 | do { \
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150 | LC_SET((pt)->lc); \
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151 | if(!(condition)) { \
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152 | return PT_WAITING; \
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153 | } \
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154 | } while(0)
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155 |
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156 | /**
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157 | * Block and wait while condition is true.
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158 | *
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159 | * This function blocks and waits while condition is true. See
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160 | * PT_WAIT_UNTIL().
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161 | *
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162 | * \param pt A pointer to the protothread control structure.
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163 | * \param cond The condition.
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164 | *
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165 | * \hideinitializer
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166 | */
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167 | #define PT_WAIT_WHILE(pt, cond) PT_WAIT_UNTIL((pt), !(cond))
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168 |
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169 | /** @} */
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170 |
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171 | /**
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172 | * \name Hierarchical protothreads
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173 | * @{
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174 | */
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175 |
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176 | /**
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177 | * Block and wait until a child protothread completes.
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178 | *
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179 | * This macro schedules a child protothread. The current protothread
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180 | * will block until the child protothread completes.
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181 | *
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182 | * \note The child protothread must be manually initialized with the
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183 | * PT_INIT() function before this function is used.
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184 | *
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185 | * \param pt A pointer to the protothread control structure.
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186 | * \param thread The child protothread with arguments
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187 | *
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188 | * \sa PT_SPAWN()
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189 | *
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190 | * \hideinitializer
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191 | */
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192 | #define PT_WAIT_THREAD(pt, thread) PT_WAIT_WHILE((pt), PT_SCHEDULE(thread))
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193 |
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194 | /**
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195 | * Spawn a child protothread and wait until it exits.
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196 | *
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197 | * This macro spawns a child protothread and waits until it exits. The
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198 | * macro can only be used within a protothread.
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199 | *
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200 | * \param pt A pointer to the protothread control structure.
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201 | * \param child A pointer to the child protothread's control structure.
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202 | * \param thread The child protothread with arguments
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203 | *
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204 | * \hideinitializer
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205 | */
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206 | #define PT_SPAWN(pt, child, thread) \
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207 | do { \
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208 | PT_INIT((child)); \
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209 | PT_WAIT_THREAD((pt), (thread)); \
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210 | } while(0)
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211 |
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212 | /** @} */
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213 |
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214 | /**
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215 | * \name Exiting and restarting
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216 | * @{
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217 | */
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218 |
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219 | /**
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220 | * Restart the protothread.
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221 | *
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222 | * This macro will block and cause the running protothread to restart
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223 | * its execution at the place of the PT_BEGIN() call.
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224 | *
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225 | * \param pt A pointer to the protothread control structure.
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226 | *
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227 | * \hideinitializer
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228 | */
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229 | #define PT_RESTART(pt) \
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230 | do { \
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231 | PT_INIT(pt); \
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232 | return PT_WAITING; \
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233 | } while(0)
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234 |
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235 | /**
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236 | * Exit the protothread.
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237 | *
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238 | * This macro causes the protothread to exit. If the protothread was
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239 | * spawned by another protothread, the parent protothread will become
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240 | * unblocked and can continue to run.
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241 | *
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242 | * \param pt A pointer to the protothread control structure.
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243 | *
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244 | * \hideinitializer
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245 | */
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246 | #define PT_EXIT(pt) \
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247 | do { \
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248 | PT_INIT(pt); \
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249 | return PT_EXITED; \
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250 | } while(0)
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251 |
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252 | /** @} */
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253 |
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254 | /**
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255 | * \name Calling a protothread
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256 | * @{
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257 | */
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258 |
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259 | /**
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260 | * Schedule a protothread.
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261 | *
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262 | * This function shedules a protothread. The return value of the
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263 | * function is non-zero if the protothread is running or zero if the
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264 | * protothread has exited.
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265 | *
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266 | * \param f The call to the C function implementing the protothread to
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267 | * be scheduled
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268 | *
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269 | * \hideinitializer
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270 | */
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271 | #define PT_SCHEDULE(f) ((f) == PT_WAITING)
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272 |
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273 | /** @} */
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274 |
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275 | /**
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276 | * \name Yielding from a protothread
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277 | * @{
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278 | */
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279 |
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280 | /**
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281 | * Yield from the current protothread.
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282 | *
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283 | * This function will yield the protothread, thereby allowing other
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284 | * processing to take place in the system.
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285 | *
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286 | * \param pt A pointer to the protothread control structure.
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287 | *
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288 | * \hideinitializer
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289 | */
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290 | #define PT_YIELD(pt) \
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291 | do { \
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292 | PT_YIELD_FLAG = 0; \
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293 | LC_SET((pt)->lc); \
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294 | if(PT_YIELD_FLAG == 0) { \
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295 | return PT_YIELDED; \
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296 | } \
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297 | } while(0)
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298 |
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299 | /**
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300 | * \brief Yield from the protothread until a condition occurs.
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301 | * \param pt A pointer to the protothread control structure.
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302 | * \param cond The condition.
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303 | *
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304 | * This function will yield the protothread, until the
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305 | * specified condition evaluates to true.
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306 | *
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307 | *
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308 | * \hideinitializer
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309 | */
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310 | #define PT_YIELD_UNTIL(pt, cond) \
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311 | do { \
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312 | PT_YIELD_FLAG = 0; \
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313 | LC_SET((pt)->lc); \
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314 | if((PT_YIELD_FLAG == 0) || !(cond)) { \
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315 | return PT_YIELDED; \
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316 | } \
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317 | } while(0)
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318 |
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319 | /** @} */
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320 |
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321 | #endif /* __PT_H__ */
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322 |
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323 | /** @} */
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