portable/IAR/AtmelSAM9XE/portasm.s79

;/*
; * FreeRTOS Kernel <DEVELOPMENT BRANCH>
; * Copyright (C) 2021 Amazon.com, Inc. or its affiliates. All Rights Reserved.
; *
; * SPDX-License-Identifier: MIT
; *
; * 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
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; */
        RSEG ICODE:CODE
        CODE32

    EXTERN vTaskSwitchContext

    PUBLIC vPortYieldProcessor
    PUBLIC vPortStartFirstTask

#include "ISR_Support.h"

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; Starting the first task is just a matter of restoring the context that
; was created by pxPortInitialiseStack().
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
vPortStartFirstTask:
    portRESTORE_CONTEXT

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; Manual context switch function.  This is the SWI hander.
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
vPortYieldProcessor:
    ADD     LR, LR, #4          ; Add 4 to the LR to make the LR appear exactly
                                ; as if the context was saved during and IRQ
                                ; handler.

    portSAVE_CONTEXT            ; Save the context of the current task...
    LDR R0, =vTaskSwitchContext ; before selecting the next task to execute.
    mov     lr, pc
    BX R0
    portRESTORE_CONTEXT         ; Restore the context of the selected task.


    END