2 FreeRTOS V7.4.2 - Copyright (C) 2013 Real Time Engineers Ltd.
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4 FEATURES AND PORTS ARE ADDED TO FREERTOS ALL THE TIME. PLEASE VISIT
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5 http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.
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7 ***************************************************************************
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9 * FreeRTOS tutorial books are available in pdf and paperback. *
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10 * Complete, revised, and edited pdf reference manuals are also *
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13 * Purchasing FreeRTOS documentation will not only help you, by *
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14 * ensuring you get running as quickly as possible and with an *
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15 * in-depth knowledge of how to use FreeRTOS, it will also help *
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16 * the FreeRTOS project to continue with its mission of providing *
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17 * professional grade, cross platform, de facto standard solutions *
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18 * for microcontrollers - completely free of charge! *
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20 * >>> See http://www.FreeRTOS.org/Documentation for details. <<< *
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22 * Thank you for using FreeRTOS, and thank you for your support! *
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24 ***************************************************************************
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27 This file is part of the FreeRTOS distribution.
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29 FreeRTOS is free software; you can redistribute it and/or modify it under
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30 the terms of the GNU General Public License (version 2) as published by the
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31 Free Software Foundation AND MODIFIED BY the FreeRTOS exception.
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33 >>>>>>NOTE<<<<<< The modification to the GPL is included to allow you to
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34 distribute a combined work that includes FreeRTOS without being obliged to
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35 provide the source code for proprietary components outside of the FreeRTOS
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38 FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY
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39 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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40 FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
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41 details. You should have received a copy of the GNU General Public License
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42 and the FreeRTOS license exception along with FreeRTOS; if not it can be
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43 viewed here: http://www.freertos.org/a00114.html and also obtained by
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44 writing to Real Time Engineers Ltd., contact details for whom are available
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45 on the FreeRTOS WEB site.
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49 ***************************************************************************
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51 * Having a problem? Start by reading the FAQ "My application does *
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52 * not run, what could be wrong?" *
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54 * http://www.FreeRTOS.org/FAQHelp.html *
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56 ***************************************************************************
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59 http://www.FreeRTOS.org - Documentation, books, training, latest versions,
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60 license and Real Time Engineers Ltd. contact details.
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62 http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
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63 including FreeRTOS+Trace - an indispensable productivity tool, and our new
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64 fully thread aware and reentrant UDP/IP stack.
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66 http://www.OpenRTOS.com - Real Time Engineers ltd license FreeRTOS to High
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67 Integrity Systems, who sell the code with commercial support,
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68 indemnification and middleware, under the OpenRTOS brand.
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70 http://www.SafeRTOS.com - High Integrity Systems also provide a safety
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71 engineered and independently SIL3 certified version for use in safety and
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72 mission critical applications that require provable dependability.
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75 /*-----------------------------------------------------------
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76 * Implementation of functions defined in portable.h for the ST STR71x ARM7
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78 *----------------------------------------------------------*/
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80 /* Library includes. */
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84 /* Standard includes. */
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87 /* Scheduler includes. */
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88 #include "FreeRTOS.h"
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91 /* Constants required to setup the initial stack. */
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92 #define portINITIAL_SPSR ( ( portSTACK_TYPE ) 0x1f ) /* System mode, ARM mode, interrupts enabled. */
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93 #define portTHUMB_MODE_BIT ( ( portSTACK_TYPE ) 0x20 )
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94 #define portINSTRUCTION_SIZE ( ( portSTACK_TYPE ) 4 )
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96 /* Constants required to handle critical sections. */
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97 #define portNO_CRITICAL_NESTING ( ( unsigned long ) 0 )
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99 #define portMICROS_PER_SECOND 1000000
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101 /*-----------------------------------------------------------*/
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103 /* Setup the watchdog to generate the tick interrupts. */
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104 static void prvSetupTimerInterrupt( void );
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106 /* ulCriticalNesting will get set to zero when the first task starts. It
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107 cannot be initialised to 0 as this will cause interrupts to be enabled
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108 during the kernel initialisation process. */
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109 unsigned long ulCriticalNesting = ( unsigned long ) 9999;
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111 /* Tick interrupt routines for cooperative and preemptive operation
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112 respectively. The preemptive version is not defined as __irq as it is called
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113 from an asm wrapper function. */
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114 __arm __irq void vPortNonPreemptiveTick( void );
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115 void vPortPreemptiveTick( void );
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117 /*-----------------------------------------------------------*/
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120 * Initialise the stack of a task to look exactly as if a call to
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121 * portSAVE_CONTEXT had been called.
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123 * See header file for description.
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125 portSTACK_TYPE *pxPortInitialiseStack( portSTACK_TYPE *pxTopOfStack, pdTASK_CODE pxCode, void *pvParameters )
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127 portSTACK_TYPE *pxOriginalTOS;
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129 pxOriginalTOS = pxTopOfStack;
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131 /* To ensure asserts in tasks.c don't fail, although in this case the assert
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132 is not really required. */
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135 /* Setup the initial stack of the task. The stack is set exactly as
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136 expected by the portRESTORE_CONTEXT() macro. */
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138 /* First on the stack is the return address - which in this case is the
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139 start of the task. The offset is added to make the return address appear
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140 as it would within an IRQ ISR. */
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141 *pxTopOfStack = ( portSTACK_TYPE ) pxCode + portINSTRUCTION_SIZE;
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144 *pxTopOfStack = ( portSTACK_TYPE ) 0xaaaaaaaa; /* R14 */
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146 *pxTopOfStack = ( portSTACK_TYPE ) pxOriginalTOS; /* Stack used when task starts goes in R13. */
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148 *pxTopOfStack = ( portSTACK_TYPE ) 0x12121212; /* R12 */
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150 *pxTopOfStack = ( portSTACK_TYPE ) 0x11111111; /* R11 */
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152 *pxTopOfStack = ( portSTACK_TYPE ) 0x10101010; /* R10 */
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154 *pxTopOfStack = ( portSTACK_TYPE ) 0x09090909; /* R9 */
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156 *pxTopOfStack = ( portSTACK_TYPE ) 0x08080808; /* R8 */
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158 *pxTopOfStack = ( portSTACK_TYPE ) 0x07070707; /* R7 */
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160 *pxTopOfStack = ( portSTACK_TYPE ) 0x06060606; /* R6 */
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162 *pxTopOfStack = ( portSTACK_TYPE ) 0x05050505; /* R5 */
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164 *pxTopOfStack = ( portSTACK_TYPE ) 0x04040404; /* R4 */
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166 *pxTopOfStack = ( portSTACK_TYPE ) 0x03030303; /* R3 */
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168 *pxTopOfStack = ( portSTACK_TYPE ) 0x02020202; /* R2 */
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170 *pxTopOfStack = ( portSTACK_TYPE ) 0x01010101; /* R1 */
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173 /* When the task starts is will expect to find the function parameter in
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175 *pxTopOfStack = ( portSTACK_TYPE ) pvParameters; /* R0 */
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178 /* The status register is set for system mode, with interrupts enabled. */
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179 *pxTopOfStack = ( portSTACK_TYPE ) portINITIAL_SPSR;
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181 if( ( ( unsigned long ) pxCode & 0x01UL ) != 0x00UL )
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183 /* We want the task to start in thumb mode. */
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184 *pxTopOfStack |= portTHUMB_MODE_BIT;
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189 /* Interrupt flags cannot always be stored on the stack and will
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190 instead be stored in a variable, which is then saved as part of the
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192 *pxTopOfStack = portNO_CRITICAL_NESTING;
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194 return pxTopOfStack;
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196 /*-----------------------------------------------------------*/
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198 portBASE_TYPE xPortStartScheduler( void )
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200 extern void vPortStartFirstTask( void );
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202 /* Start the timer that generates the tick ISR. Interrupts are disabled
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204 prvSetupTimerInterrupt();
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206 /* Start the first task. */
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207 vPortStartFirstTask();
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209 /* Should not get here! */
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212 /*-----------------------------------------------------------*/
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214 void vPortEndScheduler( void )
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216 /* It is unlikely that the ARM port will require this function as there
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217 is nothing to return to. */
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219 /*-----------------------------------------------------------*/
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221 /* The cooperative scheduler requires a normal IRQ service routine to
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222 simply increment the system tick. */
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223 __arm __irq void vPortNonPreemptiveTick( void )
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225 /* Increment the tick count - which may wake some tasks but as the
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226 preemptive scheduler is not being used any woken task is not given
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227 processor time no matter what its priority. */
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228 xTaskIncrementTick();
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230 /* Clear the interrupt in the watchdog and EIC. */
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234 /*-----------------------------------------------------------*/
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236 /* This function is called from an asm wrapper, so does not require the __irq
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238 void vPortPreemptiveTick( void )
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240 /* Increment the tick counter. */
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241 if( xTaskIncrementTick() != pdFALSE )
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243 /* Select a new task to execute. */
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244 vTaskSwitchContext();
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247 /* Clear the interrupt in the watchdog and EIC. */
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251 /*-----------------------------------------------------------*/
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253 static void prvSetupTimerInterrupt( void )
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255 /* Set the watchdog up to generate a periodic tick. */
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256 WDG_ECITConfig( DISABLE );
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257 WDG_CntOnOffConfig( DISABLE );
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258 WDG_PeriodValueConfig( portMICROS_PER_SECOND / configTICK_RATE_HZ );
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260 /* Setup the tick interrupt in the EIC. */
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261 EIC_IRQChannelPriorityConfig( WDG_IRQChannel, 1 );
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262 EIC_IRQChannelConfig( WDG_IRQChannel, ENABLE );
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263 EIC_IRQConfig( ENABLE );
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264 WDG_ECITConfig( ENABLE );
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266 /* Start the timer - interrupts are actually disabled at this point so
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267 it is safe to do this here. */
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268 WDG_CntOnOffConfig( ENABLE );
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270 /*-----------------------------------------------------------*/
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272 __arm __interwork void vPortEnterCritical( void )
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274 /* Disable interrupts first! */
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275 __disable_interrupt();
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277 /* Now interrupts are disabled ulCriticalNesting can be accessed
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278 directly. Increment ulCriticalNesting to keep a count of how many times
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279 portENTER_CRITICAL() has been called. */
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280 ulCriticalNesting++;
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282 /*-----------------------------------------------------------*/
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284 __arm __interwork void vPortExitCritical( void )
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286 if( ulCriticalNesting > portNO_CRITICAL_NESTING )
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288 /* Decrement the nesting count as we are leaving a critical section. */
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289 ulCriticalNesting--;
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291 /* If the nesting level has reached zero then interrupts should be
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293 if( ulCriticalNesting == portNO_CRITICAL_NESTING )
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295 __enable_interrupt();
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299 /*-----------------------------------------------------------*/
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