2 FreeRTOS V6.0.5 - Copyright (C) 2010 Real Time Engineers Ltd.
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4 ***************************************************************************
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8 * + New to FreeRTOS, *
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9 * + Wanting to learn FreeRTOS or multitasking in general quickly *
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10 * + Looking for basic training, *
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11 * + Wanting to improve your FreeRTOS skills and productivity *
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13 * then take a look at the FreeRTOS eBook *
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15 * "Using the FreeRTOS Real Time Kernel - a Practical Guide" *
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16 * http://www.FreeRTOS.org/Documentation *
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18 * A pdf reference manual is also available. Both are usually delivered *
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19 * to your inbox within 20 minutes to two hours when purchased between 8am *
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20 * and 8pm GMT (although please allow up to 24 hours in case of *
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21 * exceptional circumstances). Thank you for your support! *
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23 ***************************************************************************
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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 exception to the GPL is included to allow you to distribute
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31 a combined work that includes FreeRTOS without being obliged to provide the
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32 source code for proprietary components outside of the FreeRTOS kernel.
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33 FreeRTOS is distributed in the hope that it will be useful, but WITHOUT
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34 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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35 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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54 PUBLIC _prvStartFirstTask
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55 PUBLIC _vSoftwareInterruptISR
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57 EXTERN _pxCurrentTCB
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58 EXTERN _vTaskSwitchContext
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64 /* When starting the scheduler there is nothing that needs moving to the
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65 interrupt stack because the function is not called from an interrupt.
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66 Just ensure the current stack is the user stack. */
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69 /* Obtain the location of the stack associated with which ever task
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70 pxCurrentTCB is currently pointing to. */
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71 MOV.L #_pxCurrentTCB, R15
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75 /* Restore the registers from the stack of the task pointed to by
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79 /* Accumulator low 32 bits. */
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83 /* Accumulator high 32 bits. */
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87 /* Floating point status word. */
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90 /* R1 to R15 - R0 is not included as it is the SP. */
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93 /* This pops the remaining registers. */
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98 /*-----------------------------------------------------------*/
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100 _vSoftwareInterruptISR:
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102 /* Re-enable interrupts. */
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105 /* Move the data that was automatically pushed onto the interrupt stack when
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106 the interrupt occurred from the interrupt stack to the user stack.
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108 R15 is saved before it is clobbered. */
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111 /* Read the user stack pointer. */
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114 /* Move the address down to the data being moved. */
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118 /* Copy the data across, R15, then PC, then PSW. */
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119 MOV.L [ R0 ], [ R15 ]
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120 MOV.L 4[ R0 ], 4[ R15 ]
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121 MOV.L 8[ R0 ], 8[ R15 ]
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123 /* Move the interrupt stack pointer to its new correct position. */
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126 /* All the rest of the registers are saved directly to the user stack. */
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129 /* Save the rest of the general registers (R15 has been saved already). */
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132 /* Save the FPSW and accumulator. */
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141 /* Shifted left as it is restored to the low order word. */
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145 /* Save the stack pointer to the TCB. */
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146 MOV.L #_pxCurrentTCB, R15
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147 MOV.L [ R15 ], R15
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150 /* Ensure the interrupt mask is set to the syscall priority while the kernel
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151 structures are being accessed. */
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154 /* Select the next task to run. */
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155 BSR.A _vTaskSwitchContext
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157 /* Reset the interrupt mask as no more data structure access is required. */
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160 /* Load the stack pointer of the task that is now selected as the Running
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161 state task from its TCB. */
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162 MOV.L #_pxCurrentTCB,R15
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163 MOV.L [ R15 ], R15
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166 /* Restore the context of the new task. The PSW (Program Status Word) and
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167 PC will be popped by the RTE instruction. */
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179 /*:: i(configMAX_SYSCALL_INTERRUPT_PRIORITY), i(configKERNEL_INTERRUPT_PRIORITY)*/
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180 /*-----------------------------------------------------------*/
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