2 * FreeRTOS Kernel V10.3.0
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3 * Copyright (C) 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
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5 * Permission is hereby granted, free of charge, to any person obtaining a copy of
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6 * this software and associated documentation files (the "Software"), to deal in
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7 * the Software without restriction, including without limitation the rights to
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8 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
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9 * the Software, and to permit persons to whom the Software is furnished to do so,
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10 * subject to the following conditions:
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12 * The above copyright notice and this permission notice shall be included in all
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13 * copies or substantial portions of the Software.
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15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
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17 * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
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18 * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
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19 * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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20 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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22 * http://www.FreeRTOS.org
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23 * http://aws.amazon.com/freertos
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25 * 1 tab == 4 spaces!
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28 /* Variables used by scheduler */
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29 .extern _pxCurrentTCB
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30 .extern _usCriticalNesting
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33 * portSAVE_CONTEXT MACRO
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34 * Saves the context of the general purpose registers, CS and ES (only in far
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35 * memory mode) registers the usCriticalNesting Value and the Stack Pointer
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36 * of the active Task onto the task stack
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38 .macro portSAVE_CONTEXT
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42 /* Save AX Register to stack. */
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45 /* Save CS register. */
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48 /* Save ES register. */
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51 /* Save the remaining general purpose registers from bank 0. */
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54 /* Save the other register banks - only necessary in the GCC port. */
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65 /* Registers in bank 3 are for ISR use only so don't need saving. */
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67 /* Save the usCriticalNesting value. */
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68 MOVW AX, !_usCriticalNesting
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70 /* Save the Stack pointer. */
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71 MOVW AX, !_pxCurrentTCB
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75 /* Switch stack pointers. */
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76 movw sp,#_stack /* Set stack pointer */
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82 * portRESTORE_CONTEXT MACRO
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83 * Restores the task Stack Pointer then use this to restore usCriticalNesting,
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84 * general purpose registers and the CS and ES (only in far memory mode)
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85 * of the selected task from the task stack
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87 .macro portRESTORE_CONTEXT MACRO
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89 /* Restore the Stack pointer. */
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90 MOVW AX, !_pxCurrentTCB
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94 /* Restore usCriticalNesting value. */
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96 MOVW !_usCriticalNesting, AX
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97 /* Restore the alternative register banks - only necessary in the GCC
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98 port. Register bank 3 is dedicated for interrupts use so is not saved or
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111 /* Restore the necessary general purpose registers. */
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114 /* Restore the ES register. */
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117 /* Restore the CS register. */
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120 /* Restore general purpose register HL. */
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