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;/*
; * FreeRTOS Kernel V10.5.1
; * 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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