2 * FreeRTOS Kernel V10.0.1
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3 * Copyright (C) 2017 Amazon.com, Inc. or its affiliates. All Rights Reserved.
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5 * Permission is hereby granted, free of charge, to any person obtaining a copy of
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6 * this software and associated documentation files (the "Software"), to deal in
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7 * the Software without restriction, including without limitation the rights to
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8 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
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9 * the Software, and to permit persons to whom the Software is furnished to do so,
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10 * subject to the following conditions:
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12 * The above copyright notice and this permission notice shall be included in all
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13 * copies or substantial portions of the Software.
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15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
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17 * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
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18 * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
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19 * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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20 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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22 * http://www.FreeRTOS.org
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23 * http://aws.amazon.com/freertos
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25 * 1 tab == 4 spaces!
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28 /*-----------------------------------------------------------
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29 * Implementation of functions defined in portable.h for the RX200 port.
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30 *----------------------------------------------------------*/
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32 /* Scheduler includes. */
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33 #include "FreeRTOS.h"
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36 /* Library includes. */
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39 /* Hardware specifics. */
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40 #include "iodefine.h"
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42 /*-----------------------------------------------------------*/
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44 /* Tasks should start with interrupts enabled and in Supervisor mode, therefore
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45 PSW is set with U and I set, and PM and IPL clear. */
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46 #define portINITIAL_PSW ( ( StackType_t ) 0x00030000 )
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48 /*-----------------------------------------------------------*/
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50 /* The following lines are to ensure vSoftwareInterruptEntry can be referenced,
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51 and therefore installed in the vector table, when the FreeRTOS code is built
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53 extern BaseType_t vSoftwareInterruptEntry;
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54 const BaseType_t * p_vSoftwareInterruptEntry = &vSoftwareInterruptEntry;
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56 /*-----------------------------------------------------------*/
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59 * Function to start the first task executing - written in asm code as direct
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60 * access to registers is required.
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62 static void prvStartFirstTask( void );
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65 * Software interrupt handler. Performs the actual context switch (saving and
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66 * restoring of registers). Written in asm code as direct register access is
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69 static void prvYieldHandler( void );
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72 * The entry point for the software interrupt handler. This is the function
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73 * that calls the inline asm function prvYieldHandler(). It is installed in
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74 * the vector table, but the code that installs it is in prvYieldHandler rather
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75 * than using a #pragma.
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77 void vSoftwareInterruptISR( void );
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79 /*-----------------------------------------------------------*/
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81 /* This is accessed by the inline assembler functions so is file scope for
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83 extern void *pxCurrentTCB;
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84 extern void vTaskSwitchContext( void );
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86 /*-----------------------------------------------------------*/
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89 * See header file for description.
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91 StackType_t *pxPortInitialiseStack( StackType_t *pxTopOfStack, TaskFunction_t pxCode, void *pvParameters )
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93 /* Offset to end up on 8 byte boundary. */
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96 /* R0 is not included as it is the stack pointer. */
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97 *pxTopOfStack = 0x00;
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99 *pxTopOfStack = 0x00;
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101 *pxTopOfStack = portINITIAL_PSW;
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103 *pxTopOfStack = ( StackType_t ) pxCode;
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105 /* When debugging it can be useful if every register is set to a known
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106 value. Otherwise code space can be saved by just setting the registers
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107 that need to be set. */
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108 #ifdef USE_FULL_REGISTER_INITIALISATION
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111 *pxTopOfStack = 0x12345678; /* r15. */
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113 *pxTopOfStack = 0xaaaabbbb;
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115 *pxTopOfStack = 0xdddddddd;
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117 *pxTopOfStack = 0xcccccccc;
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119 *pxTopOfStack = 0xbbbbbbbb;
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121 *pxTopOfStack = 0xaaaaaaaa;
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123 *pxTopOfStack = 0x99999999;
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125 *pxTopOfStack = 0x88888888;
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127 *pxTopOfStack = 0x77777777;
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129 *pxTopOfStack = 0x66666666;
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131 *pxTopOfStack = 0x55555555;
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133 *pxTopOfStack = 0x44444444;
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135 *pxTopOfStack = 0x33333333;
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137 *pxTopOfStack = 0x22222222;
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142 pxTopOfStack -= 15;
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146 *pxTopOfStack = ( StackType_t ) pvParameters; /* R1 */
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148 *pxTopOfStack = 0x12345678; /* Accumulator. */
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150 *pxTopOfStack = 0x87654321; /* Accumulator. */
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152 return pxTopOfStack;
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154 /*-----------------------------------------------------------*/
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156 BaseType_t xPortStartScheduler( void )
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158 extern void vApplicationSetupTimerInterrupt( void );
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160 /* Use pxCurrentTCB just so it does not get optimised away. */
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161 if( pxCurrentTCB != NULL )
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163 /* Call an application function to set up the timer that will generate the
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164 tick interrupt. This way the application can decide which peripheral to
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165 use. A demo application is provided to show a suitable example. */
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166 vApplicationSetupTimerInterrupt();
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168 /* Enable the software interrupt. */
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169 _IEN( _ICU_SWINT ) = 1;
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171 /* Ensure the software interrupt is clear. */
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172 _IR( _ICU_SWINT ) = 0;
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174 /* Ensure the software interrupt is set to the kernel priority. */
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175 _IPR( _ICU_SWINT ) = configKERNEL_INTERRUPT_PRIORITY;
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177 /* Start the first task. */
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178 prvStartFirstTask();
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181 /* Just to make sure the function is not optimised away. */
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182 ( void ) vSoftwareInterruptISR();
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184 /* Should not get here. */
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187 /*-----------------------------------------------------------*/
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189 #pragma inline_asm prvStartFirstTask
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190 static void prvStartFirstTask( void )
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192 /* When starting the scheduler there is nothing that needs moving to the
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193 interrupt stack because the function is not called from an interrupt.
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194 Just ensure the current stack is the user stack. */
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197 /* Obtain the location of the stack associated with which ever task
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198 pxCurrentTCB is currently pointing to. */
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199 MOV.L #_pxCurrentTCB, R15
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203 /* Restore the registers from the stack of the task pointed to by
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206 MVTACLO R15 /* Accumulator low 32 bits. */
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208 MVTACHI R15 /* Accumulator high 32 bits. */
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209 POPM R1-R15 /* R1 to R15 - R0 is not included as it is the SP. */
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210 RTE /* This pops the remaining registers. */
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214 /*-----------------------------------------------------------*/
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216 #pragma interrupt ( vTickISR( vect = _VECT( configTICK_VECTOR ), enable ) )
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217 void vTickISR( void )
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219 /* Increment the tick, and perform any processing the new tick value
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221 set_ipl( configMAX_SYSCALL_INTERRUPT_PRIORITY );
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223 if( xTaskIncrementTick() != pdFALSE )
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228 set_ipl( configKERNEL_INTERRUPT_PRIORITY );
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230 /*-----------------------------------------------------------*/
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232 void vSoftwareInterruptISR( void )
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236 /*-----------------------------------------------------------*/
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238 #pragma inline_asm prvYieldHandler
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239 static void prvYieldHandler( void )
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241 /* Re-enable interrupts. */
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244 /* Move the data that was automatically pushed onto the interrupt stack when
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245 the interrupt occurred from the interrupt stack to the user stack.
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247 R15 is saved before it is clobbered. */
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250 /* Read the user stack pointer. */
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253 /* Move the address down to the data being moved. */
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257 /* Copy the data across. */
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258 MOV.L [ R0 ], [ R15 ] ; R15
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259 MOV.L 4[ R0 ], 4[ R15 ] ; PC
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260 MOV.L 8[ R0 ], 8[ R15 ] ; PSW
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262 /* Move the interrupt stack pointer to its new correct position. */
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265 /* All the rest of the registers are saved directly to the user stack. */
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268 /* Save the rest of the general registers (R15 has been saved already). */
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271 /* Save the accumulator. */
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274 MVFACMI R15 ; Middle order word.
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275 SHLL #16, R15 ; Shifted left as it is restored to the low order word.
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278 /* Save the stack pointer to the TCB. */
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279 MOV.L #_pxCurrentTCB, R15
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283 /* Ensure the interrupt mask is set to the syscall priority while the kernel
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284 structures are being accessed. */
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285 MVTIPL #configMAX_SYSCALL_INTERRUPT_PRIORITY
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287 /* Select the next task to run. */
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288 BSR.A _vTaskSwitchContext
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290 /* Reset the interrupt mask as no more data structure access is required. */
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291 MVTIPL #configKERNEL_INTERRUPT_PRIORITY
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293 /* Load the stack pointer of the task that is now selected as the Running
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294 state task from its TCB. */
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295 MOV.L #_pxCurrentTCB,R15
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299 /* Restore the context of the new task. The PSW (Program Status Word) and
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300 PC will be popped by the RTE instruction. */
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310 /*-----------------------------------------------------------*/
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312 void vPortEndScheduler( void )
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314 /* Not implemented in ports where there is nothing to return to.
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315 Artificially force an assert. */
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316 configASSERT( pxCurrentTCB == NULL );
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318 /* The following line is just to prevent the symbol getting optimised away. */
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319 ( void ) vTaskSwitchContext();
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321 /*-----------------------------------------------------------*/
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