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- ;/*
- ; * FreeRTOS Kernel V10.4.6
- ; * 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
- ; *
- ; */
- RSEG ICODE:CODE
- CODE32
- EXTERN vTaskSwitchContext
- EXTERN xTaskIncrementTick
- PUBLIC vPortYieldProcessor
- PUBLIC vPortPreemptiveTick
- PUBLIC vPortStartFirstTask
- #include "AT91SAM7S64_inc.h"
- #include "ISR_Support.h"
- ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
- ; Starting the first task is just a matter of restoring the context that
- ; was created by pxPortInitialiseStack().
- ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
- vPortStartFirstTask:
- portRESTORE_CONTEXT
- ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
- ; 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.
- ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
- ; Preemptive context switch function. This will only ever get installed if
- ; portUSE_PREEMPTION is set to 1 in portmacro.h.
- ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
- vPortPreemptiveTick:
- portSAVE_CONTEXT ; Save the context of the current task.
- LDR R0, =xTaskIncrementTick ; Increment the tick count - this may wake a task.
- mov lr, pc
- BX R0
- CMP R0, #0
- BEQ SkipContextSwitch
- LDR R0, =vTaskSwitchContext ; Select the next task to execute.
- mov lr, pc
- BX R0
- SkipContextSwitch
- LDR R14, =AT91C_BASE_PITC ; Clear the PIT interrupt
- LDR R0, [R14, #PITC_PIVR ]
- LDR R14, =AT91C_BASE_AIC ; Mark the End of Interrupt on the AIC
- STR R14, [R14, #AIC_EOICR]
- portRESTORE_CONTEXT ; Restore the context of the selected task.
- END
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