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/*
* 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
*
*/
#include "FreeRTOSConfig.h"
#include "portasm.h"
IMPORT xTaskIncrementTick
IMPORT vTaskSwitchContext
IMPORT vPortSetupTimerInterrupt
EXPORT vTickISR
EXPORT vPortYield
EXPORT xPortStartScheduler
RSEG CODE
/*
* The RTOS tick ISR.
*
* If the cooperative scheduler is in use this simply increments the tick
* count.
*
* If the preemptive scheduler is in use a context switch can also occur.
*/
vTickISR:
portSAVE_CONTEXT
call #xTaskIncrementTick
cmp.w #0x0, R12
jeq SkipContextSwitch
call #vTaskSwitchContext
SkipContextSwitch:
portRESTORE_CONTEXT
/*-----------------------------------------------------------*/
/*
* Manual context switch called by the portYIELD() macro.
*/
vPortYield:
/* Mimic an interrupt by pushing the SR. */
push SR
/* Now the SR is stacked we can disable interrupts. */
dint
/* Save the context of the current task. */
portSAVE_CONTEXT
/* Switch to the highest priority task that is ready to run. */
call #vTaskSwitchContext
/* Restore the context of the new task. */
portRESTORE_CONTEXT
/*-----------------------------------------------------------*/
/*
* Start off the scheduler by initialising the RTOS tick timer, then restoring
* the context of the first task.
*/
xPortStartScheduler:
/* Setup the hardware to generate the tick. Interrupts are disabled
when this function is called. */
call #vPortSetupTimerInterrupt
/* Restore the context of the first task that is going to run. */
portRESTORE_CONTEXT
/*-----------------------------------------------------------*/
/* Install vTickISR as the timer A0 interrupt. */
ASEG
ORG 0xFFE0 + TIMERA0_VECTOR
_vTickISR_: DC16 vTickISR
END
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