2 ; FreeRTOS V7.4.1 - Copyright (C) 2013 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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40 ; FreeRTOS WEB site.
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42 ; 1 tab == 4 spaces!
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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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56 .ref vTaskSwitchContext
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57 .ref vTaskIncrementTick
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58 .ref ulTaskHasFPUContext
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61 ;/*-----------------------------------------------------------*/
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63 ; Save Task Context
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65 portSAVE_CONTEXT .macro
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68 ; Push R0 as we are going to use it
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71 ; Set R0 to point to the task stack pointer.
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76 ; Push the return address onto the stack.
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79 ; Now LR has been saved, it can be used instead of R0.
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82 ; Pop R0 so it can be saved onto the task stack.
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85 ; Push all the system mode registers onto the task stack.
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89 ; Push the SPSR onto the task stack.
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93 .if (__TI_VFP_SUPPORT__)
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94 ;Determine if the task maintains an FPU context.
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95 LDR R0, ulFPUContextConst
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101 ; If the task is not using a floating point context then skip the
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102 ; saving of the FPU registers.
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104 FSTMDBD LR!, {D0-D15}
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112 ; Store the new top of stack for the task.
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113 LDR R0, pxCurrentTCBConst
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119 ;/*-----------------------------------------------------------*/
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121 ; Restore Task Context
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123 portRESTORE_CONTEXT .macro
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124 LDR R0, pxCurrentTCBConst
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128 .if (__TI_VFP_SUPPORT__)
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129 ; The floating point context flag is the first thing on the stack.
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130 LDR R0, ulFPUContextConst
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137 ; If the task is not using a floating point context then skip the
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138 ; VFP register loads.
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141 ; Restore the floating point context.
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143 FLDMIAD LR!, {D0-D15}
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147 ; Get the SPSR from the stack.
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151 ; Restore all system mode registers for the task.
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152 LDMFD LR, {R0-R14}^
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154 ; Restore the return address.
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157 ; And return - correcting the offset in the LR to obtain the
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162 ;/*-----------------------------------------------------------*/
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163 ; Start the first task by restoring its context.
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165 .def vPortStartFirstTask
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167 vPortStartFirstTask:
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168 portRESTORE_CONTEXT
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170 ;/*-----------------------------------------------------------*/
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171 ; Yield to another task.
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173 .def vPortYieldProcessor
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175 vPortYieldProcessor:
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176 ; Within an IRQ ISR the link register has an offset from the true return
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177 ; address. SWI doesn't do this. Add the offset manually so the ISR
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178 ; return code can be used.
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181 ; First save the context of the current task.
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184 ; Select the next task to execute. */
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185 BL vTaskSwitchContext
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187 ; Restore the context of the task selected to execute.
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188 portRESTORE_CONTEXT
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190 ;/*-----------------------------------------------------------*/
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191 ; Yield to another task from within the FreeRTOS API
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193 .def vPortYeildWithinAPI
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195 vPortYeildWithinAPI:
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196 ; Save the context of the current task.
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204 ; Select the next task to execute. */
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205 BL vTaskSwitchContext
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207 ; Restore the context of the task selected to execute.
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208 portRESTORE_CONTEXT
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210 ;/*-----------------------------------------------------------*/
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213 .def vPortPreemptiveTick
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215 vPortPreemptiveTick:
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217 ; Save the context of the current task.
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220 ; Clear interrupt flag
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226 ; Increment the tick count, making any adjustments to the blocked lists
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227 ; that may be necessary.
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228 BL vTaskIncrementTick
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230 ; Select the next task to execute.
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231 BL vTaskSwitchContext
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233 ; Restore the context of the task selected to execute.
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234 portRESTORE_CONTEXT
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236 ;-------------------------------------------------------------------------------
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238 .if (__TI_VFP_SUPPORT__)
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240 .def vPortInitialiseFPSCR
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242 vPortInitialiseFPSCR:
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248 .endif ;__TI_VFP_SUPPORT__
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251 pxCurrentTCBConst .word pxCurrentTCB
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252 ulFPUContextConst .word ulTaskHasFPUContext
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253 ;-------------------------------------------------------------------------------
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