2 ; * FreeRTOS SMP Kernel V202110.00
3 ; * Copyright (C) 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
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25 ; * 1 tab == 4 spaces!
28 #include "FreeRTOSConfig.h"
30 ; Variables used by scheduler
31 ;------------------------------------------------------------------------------
33 EXTERN usCriticalNesting
35 ;------------------------------------------------------------------------------
36 ; portSAVE_CONTEXT MACRO
37 ; Saves the context of the general purpose registers, CS and ES (only in far
38 ; memory mode) registers the usCriticalNesting Value and the Stack Pointer
39 ; of the active Task onto the task stack
40 ;------------------------------------------------------------------------------
41 portSAVE_CONTEXT MACRO
43 PUSH AX ; Save AX Register to stack.
45 MOV A, CS ; Save CS register.
47 MOV A, ES ; Save ES register.
49 PUSH DE ; Save the remaining general purpose registers.
51 MOVW AX, usCriticalNesting ; Save the usCriticalNesting value.
53 MOVW AX, pxCurrentTCB ; Save the Stack pointer.
58 ;------------------------------------------------------------------------------
60 ;------------------------------------------------------------------------------
61 ; portRESTORE_CONTEXT MACRO
62 ; Restores the task Stack Pointer then use this to restore usCriticalNesting,
63 ; general purpose registers and the CS and ES (only in far memory mode)
64 ; of the selected task from the task stack
65 ;------------------------------------------------------------------------------
66 portRESTORE_CONTEXT MACRO
67 MOVW AX, pxCurrentTCB ; Restore the Stack pointer.
71 POP AX ; Restore usCriticalNesting value.
72 MOVW usCriticalNesting, AX
73 POP BC ; Restore the necessary general purpose registers.
75 POP AX ; Restore the ES register.
77 XCH A, X ; Restore the CS register.
79 POP HL ; Restore general purpose register HL.
82 ;------------------------------------------------------------------------------