2 FreeRTOS V8.2.0rc1 - Copyright (C) 2014 Real Time Engineers Ltd.
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5 VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.
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7 This file is part of the FreeRTOS distribution.
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9 FreeRTOS is free software; you can redistribute it and/or modify it under
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10 the terms of the GNU General Public License (version 2) as published by the
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11 Free Software Foundation >>!AND MODIFIED BY!<< the FreeRTOS exception.
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13 >>! NOTE: The modification to the GPL is included to allow you to !<<
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14 >>! distribute a combined work that includes FreeRTOS without being !<<
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15 >>! obliged to provide the source code for proprietary components !<<
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16 >>! outside of the FreeRTOS kernel. !<<
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18 FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY
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19 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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20 FOR A PARTICULAR PURPOSE. Full license text is available on the following
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21 link: http://www.freertos.org/a00114.html
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25 ***************************************************************************
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27 * Having a problem? Start by reading the FAQ "My application does *
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28 * not run, what could be wrong?". Have you defined configASSERT()? *
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30 * http://www.FreeRTOS.org/FAQHelp.html *
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32 ***************************************************************************
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34 ***************************************************************************
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36 * FreeRTOS provides completely free yet professionally developed, *
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37 * robust, strictly quality controlled, supported, and cross *
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38 * platform software that is more than just the market leader, it *
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39 * is the industry's de facto standard. *
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41 * Help yourself get started quickly while simultaneously helping *
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42 * to support the FreeRTOS project by purchasing a FreeRTOS *
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43 * tutorial book, reference manual, or both: *
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44 * http://www.FreeRTOS.org/Documentation *
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46 ***************************************************************************
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48 ***************************************************************************
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50 * Investing in training allows your team to be as productive as *
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51 * possible as early as possible, lowering your overall development *
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52 * cost, and enabling you to bring a more robust product to market *
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53 * earlier than would otherwise be possible. Richard Barry is both *
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54 * the architect and key author of FreeRTOS, and so also the world's *
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55 * leading authority on what is the world's most popular real time *
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56 * kernel for deeply embedded MCU designs. Obtaining your training *
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57 * from Richard ensures your team will gain directly from his in-depth *
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58 * product knowledge and years of usage experience. Contact Real Time *
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59 * Engineers Ltd to enquire about the FreeRTOS Masterclass, presented *
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60 * by Richard Barry: http://www.FreeRTOS.org/contact
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62 ***************************************************************************
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64 ***************************************************************************
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66 * You are receiving this top quality software for free. Please play *
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67 * fair and reciprocate by reporting any suspected issues and *
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68 * participating in the community forum: *
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69 * http://www.FreeRTOS.org/support *
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73 ***************************************************************************
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75 http://www.FreeRTOS.org - Documentation, books, training, latest versions,
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76 license and Real Time Engineers Ltd. contact details.
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78 http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
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79 including FreeRTOS+Trace - an indispensable productivity tool, a DOS
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80 compatible FAT file system, and our tiny thread aware UDP/IP stack.
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82 http://www.FreeRTOS.org/labs - Where new FreeRTOS products go to incubate.
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83 Come and try FreeRTOS+TCP, our new open source TCP/IP stack for FreeRTOS.
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85 http://www.OpenRTOS.com - Real Time Engineers ltd license FreeRTOS to High
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86 Integrity Systems ltd. to sell under the OpenRTOS brand. Low cost OpenRTOS
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87 licenses offer ticketed support, indemnification and commercial middleware.
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89 http://www.SafeRTOS.com - High Integrity Systems also provide a safety
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90 engineered and independently SIL3 certified version for use in safety and
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91 mission critical applications that require provable dependability.
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96 #include "FreeRTOSConfig.h"
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98 #define portCONTEXT_SIZE 160
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99 #define portEPC_STACK_LOCATION 152
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100 #define portSTATUS_STACK_LOCATION 156
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102 /******************************************************************/
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103 .macro portSAVE_CONTEXT
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105 /* Make room for the context. First save the current status so it can be
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106 manipulated, and the cause and EPC registers so their original values are
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108 mfc0 k0, _CP0_CAUSE
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109 addiu sp, sp, -portCONTEXT_SIZE
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110 mfc0 k1, _CP0_STATUS
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112 /* Also save s6 and s5 so they can be used. Any nesting interrupts should
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113 maintain the values of these registers across the ISR. */
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116 sw k1, portSTATUS_STACK_LOCATION(sp)
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118 /* Prepare to enable interrupts above the current priority. */
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121 srl k0, k0, 0x7 /* This copies the MSB of the IPL, but it would be an error if it was set anyway. */
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125 /* s5 is used as the frame pointer. */
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128 /* Check the nesting count value. */
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129 la k0, uxInterruptNesting
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132 /* If the nesting count is 0 then swap to the the system stack, otherwise
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133 the system stack is already being used. */
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137 /* Swap to the system stack. */
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138 la sp, xISRStackTop
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141 /* Increment and save the nesting count. */
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145 /* s6 holds the EPC value, this is saved after interrupts are re-enabled. */
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148 /* Re-enable interrupts. */
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149 mtc0 k1, _CP0_STATUS
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151 /* Save the context into the space just created. s6 is saved again
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152 here as it now contains the EPC value. No other s registers need be
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172 sw s6, portEPC_STACK_LOCATION(s5)
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175 /* Save the AC0, AC1, AC2, AC3 registers from the DSP. s6 is used as a
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176 scratch register. */
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192 /* Save the DSP Control register */
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196 /* ac0 is done separately to match the MX port. */
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202 /* Update the task stack pointer value if nesting is zero. */
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203 la s6, uxInterruptNesting
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209 /* Save the stack pointer. */
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210 la s6, uxSavedTaskStackPointer
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215 /******************************************************************/
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216 .macro portRESTORE_CONTEXT
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218 /* Restore the stack pointer from the TCB. This is only done if the
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219 nesting count is 1. */
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220 la s6, uxInterruptNesting
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225 la s6, uxSavedTaskStackPointer
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228 /* Restore the context. */
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244 /* Restore DSPControl. */
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254 /* s6 is loaded as it was used as a scratch register and therefore saved
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255 as part of the interrupt context. */
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276 /* Protect access to the k registers, and others. */
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280 /* Decrement the nesting count. */
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281 la k0, uxInterruptNesting
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286 lw k0, portSTATUS_STACK_LOCATION(s5)
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287 lw k1, portEPC_STACK_LOCATION(s5)
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289 /* Leave the stack in its original state. First load sp from s5, then
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290 restore s5 from the stack. */
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293 addiu sp, sp, portCONTEXT_SIZE
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295 mtc0 k0, _CP0_STATUS
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