;/*
; * FreeRTOS Kernel V10.2.1
; * Copyright (C) 2019 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.
; *
; * http://www.FreeRTOS.org
; * http://aws.amazon.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
;
------------------------------------------------------------------------------
