2 FreeRTOS.org V5.3.1 - Copyright (C) 2003-2009 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 it
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7 under the terms of the GNU General Public License (version 2) as published
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8 by the Free Software Foundation and modified by the FreeRTOS exception.
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9 **NOTE** The exception to the GPL is included to allow you to distribute a
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10 combined work that includes FreeRTOS.org without being obliged to provide
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11 the source code for any proprietary components. Alternative commercial
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12 license and support terms are also available upon request. See the
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13 licensing section of http://www.FreeRTOS.org for full details.
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15 FreeRTOS.org is distributed in the hope that it will be useful, but WITHOUT
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16 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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17 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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20 You should have received a copy of the GNU General Public License along
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21 with FreeRTOS.org; if not, write to the Free Software Foundation, Inc., 59
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22 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
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25 ***************************************************************************
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27 * Get the FreeRTOS eBook! See http://www.FreeRTOS.org/Documentation *
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29 * This is a concise, step by step, 'hands on' guide that describes both *
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30 * general multitasking concepts and FreeRTOS specifics. It presents and *
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31 * explains numerous examples that are written using the FreeRTOS API. *
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32 * Full source code for all the examples is provided in an accompanying *
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35 ***************************************************************************
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39 Please ensure to read the configuration and relevant port sections of the
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40 online documentation.
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42 http://www.FreeRTOS.org - Documentation, latest information, license and
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45 http://www.SafeRTOS.com - A version that is certified for use in safety
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48 http://www.OpenRTOS.com - Commercial support, development, porting,
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49 licensing and training services.
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53 EXTERN ulCriticalNesting
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55 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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56 ; Context save and restore macro definitions
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57 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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59 portSAVE_CONTEXT MACRO
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61 ; Push R0 as we are going to use the register.
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64 ; Set R0 to point to the task stack pointer.
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70 ; Push the return address onto the stack.
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73 ; Now we have saved LR we can use it instead of R0.
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76 ; Pop R0 so we can save it onto the system mode stack.
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79 ; Push all the system mode registers onto the task stack.
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84 ; Push the SPSR onto the task stack.
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88 LDR R0, =ulCriticalNesting
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92 ; Store the new top of stack for the task.
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93 LDR R1, =pxCurrentTCB
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100 portRESTORE_CONTEXT MACRO
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102 ; Set the LR to the task stack.
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103 LDR R1, =pxCurrentTCB
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107 ; The critical nesting depth is the first item on the stack.
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108 ; Load it into the ulCriticalNesting variable.
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109 LDR R0, =ulCriticalNesting
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113 ; Get the SPSR from the stack.
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117 ; Restore all system mode registers for the task.
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118 LDMFD LR, {R0-R14}^
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121 ; Restore the return address.
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124 ; And return - correcting the offset in the LR to obtain the
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125 ; correct address.
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