2 FreeRTOS V7.0.0 - Copyright (C) 2011 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 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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55 EXTERN ulCriticalNesting
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57 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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58 ; Context save and restore macro definitions
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59 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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61 portSAVE_CONTEXT MACRO
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63 ; Push R0 as we are going to use the register.
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66 ; Set R0 to point to the task stack pointer.
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72 ; Push the return address onto the stack.
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75 ; Now we have saved LR we can use it instead of R0.
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78 ; Pop R0 so we can save it onto the system mode stack.
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81 ; Push all the system mode registers onto the task stack.
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86 ; Push the SPSR onto the task stack.
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90 LDR R0, =ulCriticalNesting
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94 ; Store the new top of stack for the task.
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95 LDR R1, =pxCurrentTCB
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102 portRESTORE_CONTEXT MACRO
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104 ; Set the LR to the task stack.
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105 LDR R1, =pxCurrentTCB
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109 ; The critical nesting depth is the first item on the stack.
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110 ; Load it into the ulCriticalNesting variable.
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111 LDR R0, =ulCriticalNesting
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115 ; Get the SPSR from the stack.
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119 ; Restore all system mode registers for the task.
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120 LDMFD LR, {R0-R14}^
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123 ; Restore the return address.
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126 ; And return - correcting the offset in the LR to obtain the
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127 ; correct address.
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