2 FreeRTOS.org V4.2.0 - Copyright (C) 2003-2007 Richard Barry.
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4 This file is part of the FreeRTOS distribution.
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6 FreeRTOS 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 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; 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, 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 See http://www.FreeRTOS.org for documentation, latest information, license
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28 and contact details. Please ensure to read the configuration and relevant
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29 port sections of the online documentation.
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30 ***************************************************************************
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34 EXTERN ulCriticalNesting
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36 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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37 ; Context save and restore macro definitions
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38 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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40 portSAVE_CONTEXT MACRO
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42 ; Push R0 as we are going to use the register.
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45 ; Set R0 to point to the task stack pointer.
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51 ; Push the return address onto the stack.
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54 ; Now we have saved LR we can use it instead of R0.
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57 ; Pop R0 so we can save it onto the system mode stack.
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60 ; Push all the system mode registers onto the task stack.
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65 ; Push the SPSR onto the task stack.
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69 LDR R0, =ulCriticalNesting
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73 ; Store the new top of stack for the task.
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74 LDR R1, =pxCurrentTCB
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81 portRESTORE_CONTEXT MACRO
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83 ; Set the LR to the task stack.
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84 LDR R1, =pxCurrentTCB
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88 ; The critical nesting depth is the first item on the stack.
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89 ; Load it into the ulCriticalNesting variable.
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90 LDR R0, =ulCriticalNesting
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94 ; Get the SPSR from the stack.
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98 ; Restore all system mode registers for the task.
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102 ; Restore the return address.
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105 ; And return - correcting the offset in the LR to obtain the
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106 ; correct address.
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