/*
 * FreeRTOS Kernel <DEVELOPMENT BRANCH>
 * 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!
 */

/* 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
 */
	.macro portSAVE_CONTEXT

	SEL 	RB0

	/* Save AX Register to stack. */
	PUSH	AX
	PUSH	HL
	/* Save CS register. */
	MOV 	A, CS
	XCH		A, X
	/* Save ES register. */
	MOV		A, ES
	PUSH	AX
	/* Save the remaining general purpose registers from bank 0. */
	PUSH	DE
	PUSH	BC
	/* Save the other register banks - only necessary in the GCC port. */
	SEL		RB1
	PUSH	AX
	PUSH	BC
	PUSH	DE
	PUSH	HL
	SEL		RB2
	PUSH	AX
	PUSH	BC
	PUSH	DE
	PUSH	HL
	/* Registers in bank 3 are for ISR use only so don't need saving. */
	SEL		RB0
	/* Save the usCriticalNesting value. */
	MOVW	AX, !_usCriticalNesting
	PUSH	AX
	/* Save the Stack pointer. */
	MOVW	AX, !_pxCurrentTCB
	MOVW	HL, AX
	MOVW	AX, SP
	MOVW	[HL], AX
	/* Switch stack pointers. */
	movw sp,#_stack /* Set stack pointer */

	.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
 */
.macro portRESTORE_CONTEXT MACRO
	SEL		RB0
	/* Restore the Stack pointer. */
	MOVW	AX, !_pxCurrentTCB
	MOVW	HL, AX
	MOVW	AX, [HL]
	MOVW	SP, AX
	/* Restore usCriticalNesting value. */
	POP		AX
	MOVW	!_usCriticalNesting, AX
	/* Restore the alternative register banks - only necessary in the GCC
	port.  Register bank 3 is dedicated for interrupts use so is not saved or
	restored. */
	SEL		RB2
	POP		HL
	POP		DE
	POP		BC
	POP		AX
	SEL		RB1
	POP		HL
	POP		DE
	POP		BC
	POP		AX
	SEL		RB0
	/* Restore the necessary general purpose registers. */
	POP		BC
	POP		DE
	/* Restore the ES register. */
	POP		AX
	MOV		ES, A
	/* Restore the CS register. */
	XCH		A, X
	MOV		CS, A
	/* Restore general purpose register HL. */
	POP		HL
	/* Restore AX. */
	POP		AX

	.endm