1 /* 2 * FreeRTOS Kernel V11.1.0 3 * Copyright (C) 2021 Amazon.com, Inc. or its affiliates. All Rights Reserved. 4 * 5 * SPDX-License-Identifier: MIT 6 * 7 * Permission is hereby granted, free of charge, to any person obtaining a copy of 8 * this software and associated documentation files (the "Software"), to deal in 9 * the Software without restriction, including without limitation the rights to 10 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of 11 * the Software, and to permit persons to whom the Software is furnished to do so, 12 * subject to the following conditions: 13 * 14 * The above copyright notice and this permission notice shall be included in all 15 * copies or substantial portions of the Software. 16 * 17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 18 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS 19 * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR 20 * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER 21 * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN 22 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. 23 * 24 * https://www.FreeRTOS.org 25 * https://github.com/FreeRTOS 26 * 27 */ 28 29 /* Variables used by scheduler */ 30 .extern _pxCurrentTCB 31 .extern _usCriticalNesting 32 33 /* 34 * portSAVE_CONTEXT MACRO 35 * Saves the context of the general purpose registers, CS and ES (only in far 36 * memory mode) registers the usCriticalNesting Value and the Stack Pointer 37 * of the active Task onto the task stack 38 */ 39 .macro portSAVE_CONTEXT 40 41 SEL RB0 42 43 /* Save AX Register to stack. */ 44 PUSH AX 45 PUSH HL 46 /* Save CS register. */ 47 MOV A, CS 48 XCH A, X 49 /* Save ES register. */ 50 MOV A, ES 51 PUSH AX 52 /* Save the remaining general purpose registers from bank 0. */ 53 PUSH DE 54 PUSH BC 55 /* Save the other register banks - only necessary in the GCC port. */ 56 SEL RB1 57 PUSH AX 58 PUSH BC 59 PUSH DE 60 PUSH HL 61 SEL RB2 62 PUSH AX 63 PUSH BC 64 PUSH DE 65 PUSH HL 66 /* Registers in bank 3 are for ISR use only so don't need saving. */ 67 SEL RB0 68 /* Save the usCriticalNesting value. */ 69 MOVW AX, !_usCriticalNesting 70 PUSH AX 71 /* Save the Stack pointer. */ 72 MOVW AX, !_pxCurrentTCB 73 MOVW HL, AX 74 MOVW AX, SP 75 MOVW[ HL ], AX 76 /* Switch stack pointers. */ 77 movw sp, # _stack /* Set stack pointer */ 78 79 .endm 80 81 82 /* 83 * portRESTORE_CONTEXT MACRO 84 * Restores the task Stack Pointer then use this to restore usCriticalNesting, 85 * general purpose registers and the CS and ES (only in far memory mode) 86 * of the selected task from the task stack 87 */ 88 .macro portRESTORE_CONTEXT MACRO 89 SEL RB0 90 /* Restore the Stack pointer. */ 91 MOVW AX, !_pxCurrentTCB 92 MOVW HL, AX 93 MOVW AX, [ HL ] 94 MOVW SP, AX 95 /* Restore usCriticalNesting value. */ 96 POP AX 97 MOVW !_usCriticalNesting, AX 98 99 /* Restore the alternative register banks - only necessary in the GCC 100 * port. Register bank 3 is dedicated for interrupts use so is not saved or 101 * restored. */ 102 SEL RB2 103 POP HL 104 POP DE 105 POP BC 106 POP AX 107 SEL RB1 108 POP HL 109 POP DE 110 POP BC 111 POP AX 112 SEL RB0 113 /* Restore the necessary general purpose registers. */ 114 POP BC 115 POP DE 116 /* Restore the ES register. */ 117 POP AX 118 MOV ES, A 119 /* Restore the CS register. */ 120 XCH A, X 121 MOV CS, A 122 /* Restore general purpose register HL. */ 123 POP HL 124 /* Restore AX. */ 125 POP AX 126 127 .endm 128
