2 FreeRTOS V6.0.5 - Copyright (C) 2010 Real Time Engineers Ltd.
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4 ***************************************************************************
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8 * + New to FreeRTOS, *
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9 * + Wanting to learn FreeRTOS or multitasking in general quickly *
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10 * + Looking for basic training, *
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11 * + Wanting to improve your FreeRTOS skills and productivity *
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13 * then take a look at the FreeRTOS eBook *
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15 * "Using the FreeRTOS Real Time Kernel - a Practical Guide" *
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16 * http://www.FreeRTOS.org/Documentation *
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18 * A pdf reference manual is also available. Both are usually delivered *
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19 * to your inbox within 20 minutes to two hours when purchased between 8am *
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20 * and 8pm GMT (although please allow up to 24 hours in case of *
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21 * exceptional circumstances). Thank you for your support! *
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23 ***************************************************************************
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25 This file is part of the FreeRTOS distribution.
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27 FreeRTOS is free software; you can redistribute it and/or modify it under
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28 the terms of the GNU General Public License (version 2) as published by the
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29 Free Software Foundation AND MODIFIED BY the FreeRTOS exception.
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30 ***NOTE*** The exception to the GPL is included to allow you to distribute
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31 a combined work that includes FreeRTOS without being obliged to provide the
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32 source code for proprietary components outside of the FreeRTOS kernel.
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33 FreeRTOS is distributed in the hope that it will be useful, but WITHOUT
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34 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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35 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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36 more details. You should have received a copy of the GNU General Public
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37 License and the FreeRTOS license exception along with FreeRTOS; if not it
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38 can be viewed here: http://www.freertos.org/a00114.html and also obtained
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39 by writing to Richard Barry, contact details for whom are available on the
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44 http://www.FreeRTOS.org - Documentation, latest information, license and
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47 http://www.SafeRTOS.com - A version that is certified for use in safety
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50 http://www.OpenRTOS.com - Commercial support, development, porting,
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51 licensing and training services.
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54 /*-----------------------------------------------------------
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55 * Implementation of functions defined in portable.h for the SH2A port.
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56 *----------------------------------------------------------*/
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58 /* Scheduler includes. */
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59 #include "FreeRTOS.h"
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62 /* Library includes. */
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65 /* Hardware specifics. */
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66 #include "iodefine.h"
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68 /*-----------------------------------------------------------*/
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70 /* Tasks should start with interrupts enabled and in Supervisor mode, therefore
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71 PSW is set with U and I set, and PM and IPL clear. */
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72 #define portINITIAL_PSW ( ( portSTACK_TYPE ) 0x00030000 )
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73 #define portINITIAL_FPSW ( ( portSTACK_TYPE ) 0x00000100 )
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75 /*-----------------------------------------------------------*/
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78 * Function to start the first task executing - written in asm code as direct
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79 * access to registers is required.
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81 static void prvStartFirstTask( void ) __attribute__((naked));
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84 * Software interrupt handler. Performs the actual context switch (saving and
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85 * restoring of registers). Written in asm code as direct register access is
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88 static void prvYieldHandler( void );
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91 * The entry point for the software interrupt handler. This is the function
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92 * that calls the inline asm function prvYieldHandler(). It is installed in
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93 * the vector table, but the code that installs it is in prvYieldHandler rather
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94 * than using a #pragma.
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96 void vSoftwareInterruptISR( void );
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98 /*-----------------------------------------------------------*/
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100 /* This is accessed by the inline assembler functions so is file scope for
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102 extern void *pxCurrentTCB;
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103 extern void vTaskSwitchContext( void );
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105 /*-----------------------------------------------------------*/
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108 * See header file for description.
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110 portSTACK_TYPE *pxPortInitialiseStack( portSTACK_TYPE *pxTopOfStack, pdTASK_CODE pxCode, void *pvParameters )
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112 /* R0 is not included as it is the stack pointer. */
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114 *pxTopOfStack = 0xdeadbeef;
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116 *pxTopOfStack = portINITIAL_PSW;
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118 *pxTopOfStack = ( portSTACK_TYPE ) pxCode;
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120 /* When debugging it can be useful if every register is set to a known
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121 value. Otherwise code space can be saved by just setting the registers
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122 that need to be set. */
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123 #ifdef USE_FULL_REGISTER_INITIALISATION
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126 *pxTopOfStack = 0xffffffff; /* r15. */
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128 *pxTopOfStack = 0xeeeeeeee;
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130 *pxTopOfStack = 0xdddddddd;
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132 *pxTopOfStack = 0xcccccccc;
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134 *pxTopOfStack = 0xbbbbbbbb;
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136 *pxTopOfStack = 0xaaaaaaaa;
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138 *pxTopOfStack = 0x99999999;
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140 *pxTopOfStack = 0x88888888;
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142 *pxTopOfStack = 0x77777777;
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144 *pxTopOfStack = 0x66666666;
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146 *pxTopOfStack = 0x55555555;
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148 *pxTopOfStack = 0x44444444;
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150 *pxTopOfStack = 0x33333333;
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152 *pxTopOfStack = 0x22222222;
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157 pxTopOfStack -= 15;
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161 *pxTopOfStack = ( portSTACK_TYPE ) pvParameters; /* R1 */
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163 *pxTopOfStack = portINITIAL_FPSW;
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165 *pxTopOfStack = 0x12345678; /* Accumulator. */
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167 *pxTopOfStack = 0x87654321; /* Accumulator. */
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169 return pxTopOfStack;
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171 /*-----------------------------------------------------------*/
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173 portBASE_TYPE xPortStartScheduler( void )
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175 extern void vApplicationSetupTimerInterrupt( void );
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177 /* Use pxCurrentTCB just so it does not get optimised away. */
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178 if( pxCurrentTCB != NULL )
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180 /* Call an application function to set up the timer that will generate the
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181 tick interrupt. This way the application can decide which peripheral to
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182 use. A demo application is provided to show a suitable example. */
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183 vApplicationSetupTimerInterrupt();
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185 /* Enable the software interrupt. */
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186 _IEN( _ICU_SWINT ) = 1;
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188 /* Ensure the software interrupt is clear. */
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189 _IR( _ICU_SWINT ) = 0;
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191 /* Ensure the software interrupt is set to the kernel priority. */
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192 _IPR( _ICU_SWINT ) = configKERNEL_INTERRUPT_PRIORITY;
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194 /* Start the first task. */
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195 prvStartFirstTask();
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198 /* Just to make sure the function is not optimised away. */
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199 ( void ) vSoftwareInterruptISR();
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201 /* Should not get here. */
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204 /*-----------------------------------------------------------*/
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206 static void prvStartFirstTask( void )
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210 /* When starting the scheduler there is nothing that needs moving to the
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211 interrupt stack because the function is not called from an interrupt.
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212 Just ensure the current stack is the user stack. */
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215 /* Obtain the location of the stack associated with which ever task
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216 pxCurrentTCB is currently pointing to. */
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217 "MOV.L #_pxCurrentTCB, R15 \n" \
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218 "MOV.L [R15], R15 \n" \
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219 "MOV.L [R15], R0 \n" \
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221 /* Restore the registers from the stack of the task pointed to by
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225 /* Accumulator low 32 bits. */
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229 /* Accumulator high 32 bits. */
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233 /* Floating point status word. */
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234 "MVTC R15, FPSW \n" \
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236 /* R1 to R15 - R0 is not included as it is the SP. */
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239 /* This pops the remaining registers. */
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245 /*-----------------------------------------------------------*/
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247 void vTickISR( void )
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249 /* Increment the tick, and perform any processing the new tick value
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251 vTaskIncrementTick();
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253 /* Only select a new task if the preemptive scheduler is being used. */
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254 #if( configUSE_PREEMPTION == 1 )
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258 /*-----------------------------------------------------------*/
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260 void vSoftwareInterruptISR( void )
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262 // prvYieldHandler();
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264 /*-----------------------------------------------------------*/
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267 #pragma inline_asm prvYieldHandler
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268 static void prvYieldHandler( void )
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270 /* Install as the software interrupt handler. */
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271 .RVECTOR _VECT( _ICU_SWINT ), _vSoftwareInterruptISR
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273 /* Re-enable interrupts. */
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276 /* Move the data that was automatically pushed onto the interrupt stack when
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277 the interrupt occurred from the interrupt stack to the user stack.
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279 R15 is saved before it is clobbered. */
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282 /* Read the user stack pointer. */
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285 /* Move the address down to the data being moved. */
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289 /* Copy the data across. */
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290 MOV.L [ R0 ], [ R15 ] ; R15
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291 MOV.L 4[ R0 ], 4[ R15 ] ; PC
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292 MOV.L 8[ R0 ], 8[ R15 ] ; PSW
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294 /* Move the interrupt stack pointer to its new correct position. */
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297 /* All the rest of the registers are saved directly to the user stack. */
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300 /* Save the rest of the general registers (R15 has been saved already). */
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303 /* Save the FPSW and accumulator. */
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308 MVFACMI R15 ; Middle order word.
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309 SHLL #16, R15 ; Shifted left as it is restored to the low order word.
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312 /* Save the stack pointer to the TCB. */
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313 MOV.L #_pxCurrentTCB, R15
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317 /* Ensure the interrupt mask is set to the syscall priority while the kernel
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318 structures are being accessed. */
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319 MVTIPL #configMAX_SYSCALL_INTERRUPT_PRIORITY
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321 /* Select the next task to run. */
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322 BSR.A _vTaskSwitchContext
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324 /* Reset the interrupt mask as no more data structure access is required. */
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325 MVTIPL #configKERNEL_INTERRUPT_PRIORITY
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327 /* Load the stack pointer of the task that is now selected as the Running
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328 state task from its TCB. */
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329 MOV.L #_pxCurrentTCB,R15
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333 /* Restore the context of the new task. The PSW (Program Status Word) and
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334 PC will be popped by the RTE instruction. */
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347 /*-----------------------------------------------------------*/
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349 void vPortEndScheduler( void )
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351 /* Not implemented as there is nothing to return to. */
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353 /* The following line is just to prevent the symbol getting optimised away. */
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354 ( void ) vTaskSwitchContext();
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356 /*-----------------------------------------------------------*/
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358 unsigned long ulPortGetIPL( void )
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361 "MVFC PSW, R1 \n" \
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362 "SHLR #28, R1 \n" \
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366 /*-----------------------------------------------------------*/
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368 void vPortSetIPL( unsigned long ulNewIPL )
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371 "MVFC PSW, R5 \n" \
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372 "SHLL #28, R1 \n" \
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373 "AND #-0F000001H, R5 \n" \
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375 "MVTC R5, PSW \n" \
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379 /*-----------------------------------------------------------*/
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