89 lines
3.3 KiB
Plaintext
89 lines
3.3 KiB
Plaintext
;/*
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; * FreeRTOS Kernel V10.2.1
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; * Copyright (C) 2019 Amazon.com, Inc. or its affiliates. All Rights Reserved.
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; *
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; * Permission is hereby granted, free of charge, to any person obtaining a copy of
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; * this software and associated documentation files (the "Software"), to deal in
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; * the Software without restriction, including without limitation the rights to
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; * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
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; * the Software, and to permit persons to whom the Software is furnished to do so,
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; * subject to the following conditions:
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; *
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; * The above copyright notice and this permission notice shall be included in all
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; * copies or substantial portions of the Software.
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; *
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; * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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; * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
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; * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
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; * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
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; * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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; * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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; *
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; * http://www.FreeRTOS.org
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; * http://aws.amazon.com/freertos
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; *
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; * 1 tab == 4 spaces!
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; */
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RSEG ICODE:CODE
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CODE32
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EXTERN vTaskSwitchContext
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EXTERN xTaskIncrementTick
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PUBLIC vPortYieldProcessor
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PUBLIC vPortPreemptiveTick
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PUBLIC vPortStartFirstTask
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#include "AT91SAM7S64_inc.h"
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#include "ISR_Support.h"
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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; Starting the first task is just a matter of restoring the context that
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; was created by pxPortInitialiseStack().
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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vPortStartFirstTask:
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portRESTORE_CONTEXT
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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; Manual context switch function. This is the SWI hander.
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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vPortYieldProcessor:
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ADD LR, LR, #4 ; Add 4 to the LR to make the LR appear exactly
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; as if the context was saved during and IRQ
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; handler.
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portSAVE_CONTEXT ; Save the context of the current task...
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LDR R0, =vTaskSwitchContext ; before selecting the next task to execute.
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mov lr, pc
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BX R0
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portRESTORE_CONTEXT ; Restore the context of the selected task.
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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; Preemptive context switch function. This will only ever get installed if
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; portUSE_PREEMPTION is set to 1 in portmacro.h.
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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vPortPreemptiveTick:
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portSAVE_CONTEXT ; Save the context of the current task.
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LDR R0, =xTaskIncrementTick ; Increment the tick count - this may wake a task.
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mov lr, pc
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BX R0
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CMP R0, #0
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BEQ SkipContextSwitch
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LDR R0, =vTaskSwitchContext ; Select the next task to execute.
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mov lr, pc
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BX R0
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SkipContextSwitch
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LDR R14, =AT91C_BASE_PITC ; Clear the PIT interrupt
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LDR R0, [R14, #PITC_PIVR ]
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LDR R14, =AT91C_BASE_AIC ; Mark the End of Interrupt on the AIC
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STR R14, [R14, #AIC_EOICR]
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portRESTORE_CONTEXT ; Restore the context of the selected task.
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END
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