2 FreeRTOS V7.2.0 - Copyright (C) 2012 Real Time Engineers Ltd.
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5 ***************************************************************************
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7 * FreeRTOS tutorial books are available in pdf and paperback. *
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8 * Complete, revised, and edited pdf reference manuals are also *
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11 * Purchasing FreeRTOS documentation will not only help you, by *
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12 * ensuring you get running as quickly as possible and with an *
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13 * in-depth knowledge of how to use FreeRTOS, it will also help *
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14 * the FreeRTOS project to continue with its mission of providing *
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15 * professional grade, cross platform, de facto standard solutions *
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16 * for microcontrollers - completely free of charge! *
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18 * >>> See http://www.FreeRTOS.org/Documentation for details. <<< *
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20 * Thank you for using FreeRTOS, and thank you for your support! *
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22 ***************************************************************************
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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 modification to the GPL is included to allow you to
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31 distribute a combined work that includes FreeRTOS without being obliged to
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32 provide the source code for proprietary components outside of the FreeRTOS
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33 kernel. FreeRTOS is distributed in the hope that it will be useful, but
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34 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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35 or 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 ***************************************************************************
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46 * Having a problem? Start by reading the FAQ "My application does *
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47 * not run, what could be wrong? *
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49 * http://www.FreeRTOS.org/FAQHelp.html *
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51 ***************************************************************************
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54 http://www.FreeRTOS.org - Documentation, training, latest information,
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55 license and contact details.
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57 http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
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58 including FreeRTOS+Trace - an indispensable productivity tool.
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60 Real Time Engineers ltd license FreeRTOS to High Integrity Systems, who sell
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61 the code with commercial support, indemnification, and middleware, under
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62 the OpenRTOS brand: http://www.OpenRTOS.com. High Integrity Systems also
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63 provide a safety engineered and independently SIL3 certified version under
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64 the SafeRTOS brand: http://www.SafeRTOS.com.
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67 #include <FreeRTOSConfig.h>
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69 /* For backward compatibility, ensure configKERNEL_INTERRUPT_PRIORITY is
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70 defined. The value zero should also ensure backward compatibility.
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71 FreeRTOS.org versions prior to V4.3.0 did not include this definition. */
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72 #ifndef configKERNEL_INTERRUPT_PRIORITY
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73 #define configKERNEL_INTERRUPT_PRIORITY 0
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80 EXTERN vPortYieldFromISR
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82 EXTERN vTaskSwitchContext
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85 PUBLIC xPortPendSVHandler
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86 PUBLIC vPortSVCHandler
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87 PUBLIC vPortStartFirstTask
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90 /*-----------------------------------------------------------*/
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96 /*-----------------------------------------------------------*/
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101 ldr r3, =pxCurrentTCB /* Get the location of the current TCB. */
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104 subs r0, r0, #32 /* Make space for the remaining low registers. */
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105 str r0, [r2] /* Save the new top of stack. */
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106 stmia r0!, {r4-r7} /* Store the low registers that are not saved automatically. */
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107 mov r4, r8 /* Store the high registers. */
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111 stmia r0!, {r4-r7}
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115 bl vTaskSwitchContext
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117 pop {r2, r3} /* lr goes in r3. r2 now holds tcb pointer. */
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120 ldr r0, [r1] /* The first item in pxCurrentTCB is the task top of stack. */
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121 adds r0, r0, #16 /* Move to the high registers. */
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122 ldmia r0!, {r4-r7} /* Pop the high registers. */
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128 msr psp, r0 /* Remember the new top of stack for the task. */
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130 subs r0, r0, #32 /* Go back for the low registers that are not automatically restored. */
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131 ldmia r0!, {r4-r7} /* Pop low registers. */
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135 /*-----------------------------------------------------------*/
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138 ldr r3, =pxCurrentTCB /* Restore the context. */
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139 ldr r1, [r3] /* Get the pxCurrentTCB address. */
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140 ldr r0, [r1] /* The first item in pxCurrentTCB is the task top of stack. */
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141 adds r0, r0, #16 /* Move to the high registers. */
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142 ldmia r0!, {r4-r7} /* Pop the high registers. */
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148 msr psp, r0 /* Remember the new top of stack for the task. */
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150 subs r0, r0, #32 /* Go back for the low registers that are not automatically restored. */
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151 ldmia r0!, {r4-r7} /* Pop low registers. */
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152 mov r1, r14 /* OR R14 with 0x0d. */
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157 /*-----------------------------------------------------------*/
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159 vPortStartFirstTask
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160 movs r0, #0x00 /* Locate the top of stack. */
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162 msr msp, r0 /* Set the msp back to the start of the stack. */
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163 cpsie i /* Globally enable interrupts. */
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164 svc 0 /* System call to start first task. */
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