2 FreeRTOS.org V4.8.0 - Copyright (C) 2003-2008 Richard Barry.
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4 This file is part of the FreeRTOS.org distribution.
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6 FreeRTOS.org is free software; you can redistribute it and/or modify
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7 it under the terms of the GNU General Public License as published by
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8 the Free Software Foundation; either version 2 of the License, or
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9 (at your option) any later version.
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11 FreeRTOS.org is distributed in the hope that it will be useful,
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12 but WITHOUT ANY WARRANTY; without even the implied warranty of
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13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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14 GNU General Public License for more details.
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16 You should have received a copy of the GNU General Public License
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17 along with FreeRTOS.org; if not, write to the Free Software
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18 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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20 A special exception to the GPL can be applied should you wish to distribute
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21 a combined work that includes FreeRTOS.org, without being obliged to provide
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22 the source code for any proprietary components. See the licensing section
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23 of http://www.FreeRTOS.org for full details of how and when the exception
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26 ***************************************************************************
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27 ***************************************************************************
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29 * SAVE TIME AND MONEY! We can port FreeRTOS.org to your own hardware, *
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30 * and even write all or part of your application on your behalf. *
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31 * See http://www.OpenRTOS.com for details of the services we provide to *
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32 * expedite your project. *
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34 ***************************************************************************
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35 ***************************************************************************
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37 Please ensure to read the configuration and relevant port sections of the
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38 online documentation.
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40 http://www.FreeRTOS.org - Documentation, latest information, license and
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43 http://www.SafeRTOS.com - A version that is certified for use in safety
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46 http://www.OpenRTOS.com - Commercial support, development, porting,
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47 licensing and training services.
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53 + Introduced the configKERNEL_INTERRUPT_PRIORITY definition.
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56 /*-----------------------------------------------------------
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57 * Implementation of functions defined in portable.h for the PIC24 port.
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58 *----------------------------------------------------------*/
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60 /* Scheduler include files. */
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61 #include "FreeRTOS.h"
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64 /* Hardware specifics. */
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65 #define portBIT_SET 1
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66 #define portTIMER_PRESCALE 8
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67 #define portINITIAL_SR 0
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69 /* Defined for backward compatability with project created prior to
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70 FreeRTOS.org V4.3.0. */
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71 #ifndef configKERNEL_INTERRUPT_PRIORITY
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72 #define configKERNEL_INTERRUPT_PRIORITY 1
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75 /* The program counter is only 23 bits. */
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76 #define portUNUSED_PR_BITS 0x7f
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78 /* Records the nesting depth of calls to portENTER_CRITICAL(). */
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79 unsigned portBASE_TYPE uxCriticalNesting = 0xef;
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81 #if configKERNEL_INTERRUPT_PRIORITY != 1
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82 #error If configKERNEL_INTERRUPT_PRIORITY is not 1 then the #32 in the following macros needs changing to equal the portINTERRUPT_BITS value, which is ( configKERNEL_INTERRUPT_PRIORITY << 5 )
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85 #ifdef MPLAB_PIC24_PORT
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87 #define portRESTORE_CONTEXT() \
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88 asm volatile( "MOV _pxCurrentTCB, W0 \n" /* Restore the stack pointer for the task. */ \
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89 "MOV [W0], W15 \n" \
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90 "POP W0 \n" /* Restore the critical nesting counter for the task. */ \
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91 "MOV W0, _uxCriticalNesting \n" \
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95 "POP RCOUNT \n" /* Restore the registers from the stack. */ \
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107 #define portSAVE_CONTEXT() \
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108 asm volatile( "PUSH SR \n" /* Save the SR used by the task.... */ \
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109 "PUSH W0 \n" /* ....then disable interrupts. */ \
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112 "PUSH W1 \n" /* Save registers to the stack. */ \
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124 "MOV _uxCriticalNesting, W0 \n" /* Save the critical nesting counter for the task. */ \
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126 "MOV _pxCurrentTCB, W0 \n" /* Save the new top of stack into the TCB. */ \
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129 #endif /* MPLAB_PIC24_PORT */
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131 #ifdef MPLAB_DSPIC_PORT
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133 #define portRESTORE_CONTEXT() \
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134 asm volatile( "MOV _pxCurrentTCB, W0 \n" /* Restore the stack pointer for the task. */ \
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135 "MOV [W0], W15 \n" \
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136 "POP W0 \n" /* Restore the critical nesting counter for the task. */ \
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137 "MOV W0, _uxCriticalNesting \n" \
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142 "POP DOSTARTH \n" \
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143 "POP DOSTARTL \n" \
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152 "POP RCOUNT \n" /* Restore the registers from the stack. */ \
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164 #define portSAVE_CONTEXT() \
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165 asm volatile( "PUSH SR \n" /* Save the SR used by the task.... */ \
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166 "PUSH W0 \n" /* ....then disable interrupts. */ \
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169 "PUSH W1 \n" /* Save registers to the stack. */ \
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186 "PUSH DOSTARTL \n" \
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187 "PUSH DOSTARTH \n" \
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192 "MOV _uxCriticalNesting, W0 \n" /* Save the critical nesting counter for the task. */ \
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194 "MOV _pxCurrentTCB, W0 \n" /* Save the new top of stack into the TCB. */ \
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195 "MOV W15, [W0] " );
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197 #endif /* MPLAB_DSPIC_PORT */
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200 * Setup the timer used to generate the tick interrupt.
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202 static void prvSetupTimerInterrupt( void );
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205 * See header file for description.
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207 portSTACK_TYPE *pxPortInitialiseStack( portSTACK_TYPE *pxTopOfStack, pdTASK_CODE pxCode, void *pvParameters )
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209 unsigned portSHORT usCode;
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212 const portSTACK_TYPE xInitialStack[] =
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228 0xcdce, /* RCOUNT */
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229 0xabac, /* TBLPAG */
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231 /* dsPIC specific registers. */
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232 #ifdef MPLAB_DSPIC_PORT
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233 0x0202, /* ACCAL */
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234 0x0303, /* ACCAH */
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235 0x0404, /* ACCAU */
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236 0x0505, /* ACCBL */
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237 0x0606, /* ACCBH */
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238 0x0707, /* ACCBU */
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239 0x0808, /* DCOUNT */
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240 0x090a, /* DOSTARTL */
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241 0x1010, /* DOSTARTH */
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242 0x1110, /* DOENDL */
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243 0x1212, /* DOENDH */
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247 /* Setup the stack as if a yield had occurred.
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249 Save the low bytes of the program counter. */
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250 usCode = ( unsigned portSHORT ) pxCode;
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251 *pxTopOfStack = ( portSTACK_TYPE ) usCode;
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254 /* Save the high byte of the program counter. This will always be zero
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255 here as it is passed in a 16bit pointer. If the address is greater than
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256 16 bits then the pointer will point to a jump table. */
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257 *pxTopOfStack = ( portSTACK_TYPE ) 0;
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260 /* Status register with interrupts enabled. */
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261 *pxTopOfStack = portINITIAL_SR;
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264 /* Parameters are passed in W0. */
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265 *pxTopOfStack = ( portSTACK_TYPE ) pvParameters;
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268 for( i = 0; i < ( sizeof( xInitialStack ) / sizeof( portSTACK_TYPE ) ); i++ )
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270 *pxTopOfStack = xInitialStack[ i ];
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274 *pxTopOfStack = CORCON;
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276 *pxTopOfStack = PSVPAG;
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279 /* Finally the critical nesting depth. */
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280 *pxTopOfStack = 0x00;
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283 return pxTopOfStack;
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285 /*-----------------------------------------------------------*/
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287 portBASE_TYPE xPortStartScheduler( void )
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289 /* Setup a timer for the tick ISR. */
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290 prvSetupTimerInterrupt();
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292 /* Restore the context of the first task to run. */
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293 portRESTORE_CONTEXT();
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295 /* Simulate the end of the yield function. */
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296 asm volatile ( "return" );
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298 /* Should not reach here. */
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301 /*-----------------------------------------------------------*/
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303 void vPortEndScheduler( void )
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305 /* It is unlikely that the scheduler for the PIC port will get stopped
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306 once running. If required disable the tick interrupt here, then return
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307 to xPortStartScheduler(). */
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309 /*-----------------------------------------------------------*/
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312 * Manual context switch. This is similar to the tick context switch,
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313 * but does not increment the tick count. It must be identical to the
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314 * tick context switch in how it stores the stack of a task.
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316 void vPortYield( void )
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318 portSAVE_CONTEXT();
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319 vTaskSwitchContext();
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320 portRESTORE_CONTEXT();
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322 /*-----------------------------------------------------------*/
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325 * Setup a timer for a regular tick.
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327 static void prvSetupTimerInterrupt( void )
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329 const unsigned portLONG ulCompareMatch = ( configCPU_CLOCK_HZ / portTIMER_PRESCALE ) / configTICK_RATE_HZ;
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331 /* Prescale of 8. */
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335 PR1 = ( unsigned portSHORT ) ulCompareMatch;
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337 /* Setup timer 1 interrupt priority. */
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338 IPC0bits.T1IP = configKERNEL_INTERRUPT_PRIORITY;
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340 /* Clear the interrupt as a starting condition. */
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343 /* Enable the interrupt. */
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346 /* Setup the prescale value. */
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347 T1CONbits.TCKPS0 = 1;
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348 T1CONbits.TCKPS1 = 0;
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350 /* Start the timer. */
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353 /*-----------------------------------------------------------*/
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355 void vPortEnterCritical( void )
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357 portDISABLE_INTERRUPTS();
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358 uxCriticalNesting++;
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360 /*-----------------------------------------------------------*/
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362 void vPortExitCritical( void )
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364 uxCriticalNesting--;
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365 if( uxCriticalNesting == 0 )
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367 portENABLE_INTERRUPTS();
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370 /*-----------------------------------------------------------*/
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372 void __attribute__((__interrupt__, auto_psv)) _T1Interrupt( void )
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374 vTaskIncrementTick();
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376 /* Clear the timer interrupt. */
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379 #if configUSE_PREEMPTION == 1
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projects / freertos / blob