;/*
; * FreeRTOS Kernel V10.4.1
; * Copyright (C) 2020 Amazon.com, Inc. or its affiliates.  All Rights Reserved.
; *
; * Permission is hereby granted, free of charge, to any person obtaining a copy of
; * this software and associated documentation files (the "Software"), to deal in
; * the Software without restriction, including without limitation the rights to
; * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
; * the Software, and to permit persons to whom the Software is furnished to do so,
; * subject to the following conditions:
; *
; * The above copyright notice and this permission notice shall be included in all
; * copies or substantial portions of the Software.
; *
; * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
; * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
; * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
; * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
; * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
; * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
; *
; * https://www.FreeRTOS.org
; * https://github.com/FreeRTOS
; *
; * 1 tab == 4 spaces!
; */

#include "FreeRTOSConfig.h"

; Variables used by scheduler
;------------------------------------------------------------------------------
	EXTERN    pxCurrentTCB
	EXTERN    usCriticalNesting

;------------------------------------------------------------------------------
;   portSAVE_CONTEXT MACRO
;   Saves the context of the general purpose registers, CS and ES (only in far
;	memory mode) registers the usCriticalNesting Value and the Stack Pointer
;   of the active Task onto the task stack
;------------------------------------------------------------------------------
portSAVE_CONTEXT MACRO

	PUSH      AX                    ; Save AX Register to stack.
	PUSH      HL
	MOV       A, CS                 ; Save CS register.
	XCH       A, X
	MOV       A, ES                 ; Save ES register.
	PUSH      AX
	PUSH      DE                    ; Save the remaining general purpose registers.
	PUSH      BC
	MOVW      AX, usCriticalNesting ; Save the usCriticalNesting value.
	PUSH      AX
	MOVW      AX, pxCurrentTCB 	    ; Save the Stack pointer.
	MOVW      HL, AX
	MOVW      AX, SP
	MOVW      [HL], AX
	ENDM
;------------------------------------------------------------------------------

;------------------------------------------------------------------------------
;   portRESTORE_CONTEXT MACRO
;   Restores the task Stack Pointer then use this to restore usCriticalNesting,
;   general purpose registers and the CS and ES (only in far memory mode)
;   of the selected task from the task stack
;------------------------------------------------------------------------------
portRESTORE_CONTEXT MACRO
	MOVW      AX, pxCurrentTCB	    ; Restore the Stack pointer.
	MOVW      HL, AX
	MOVW      AX, [HL]
	MOVW      SP, AX
	POP	      AX	                ; Restore usCriticalNesting value.
	MOVW      usCriticalNesting, AX
	POP	      BC                    ; Restore the necessary general purpose registers.
	POP	      DE
	POP       AX                    ; Restore the ES register.
	MOV       ES, A
	XCH       A, X                  ; Restore the CS register.
	MOV       CS, A
	POP       HL                    ; Restore general purpose register HL.
	POP       AX                    ; Restore AX.
	ENDM
;------------------------------------------------------------------------------