portable/IAR/AtmelSAM9XE/ISR_Support.h

;/*
; * FreeRTOS Kernel <DEVELOPMENT BRANCH>
; * Copyright (C) 2021 Amazon.com, Inc. or its affiliates.  All Rights Reserved.
; *
; * SPDX-License-Identifier: MIT
; *
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; * this software and associated documentation files (the "Software"), to deal in
; * the Software without restriction, including without limitation the rights to
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; *
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; * copies or substantial portions of the Software.
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; * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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; */
	EXTERN pxCurrentTCB
	EXTERN ulCriticalNesting

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; Context save and restore macro definitions
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

portSAVE_CONTEXT MACRO

	; Push R0 as we are going to use the register.
	STMDB	SP!, {R0}

	; Set R0 to point to the task stack pointer.
	STMDB	SP, {SP}^
	NOP
	SUB		SP, SP, #4
	LDMIA	SP!, {R0}

	; Push the return address onto the stack.
	STMDB	R0!, {LR}

	; Now we have saved LR we can use it instead of R0.
	MOV		LR, R0

	; Pop R0 so we can save it onto the system mode stack.
	LDMIA	SP!, {R0}

	; Push all the system mode registers onto the task stack.
	STMDB	LR, {R0-LR}^
	NOP
	SUB		LR, LR, #60

	; Push the SPSR onto the task stack.
	MRS		R0, SPSR
	STMDB	LR!, {R0}

	LDR		R0, =ulCriticalNesting
	LDR		R0, [R0]
	STMDB	LR!, {R0}

	; Store the new top of stack for the task.
	LDR		R1, =pxCurrentTCB
	LDR		R0, [R1]
	STR		LR, [R0]

	ENDM


portRESTORE_CONTEXT MACRO

	; Set the LR to the task stack.
	LDR		R1, =pxCurrentTCB
	LDR		R0, [R1]
	LDR		LR, [R0]

	; The critical nesting depth is the first item on the stack.
	; Load it into the ulCriticalNesting variable.
	LDR		R0, =ulCriticalNesting
	LDMFD	LR!, {R1}
	STR		R1, [R0]

	; Get the SPSR from the stack.
	LDMFD	LR!, {R0}
	MSR		SPSR_cxsf, R0

	; Restore all system mode registers for the task.
	LDMFD	LR, {R0-R14}^
	NOP

	; Restore the return address.
	LDR		LR, [LR, #+60]

	; And return - correcting the offset in the LR to obtain the
	; correct address.
	SUBS	PC, LR, #4

	ENDM