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149 lines
5.5 KiB
ArmAsm
149 lines
5.5 KiB
ArmAsm
;/*
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; FreeRTOS V7.0.2 - Copyright (C) 2011 Real Time Engineers Ltd.
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;
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;
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; ***************************************************************************
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; * *
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; * FreeRTOS tutorial books are available in pdf and paperback. *
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; * Complete, revised, and edited pdf reference manuals are also *
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; * available. *
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; * *
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; * Purchasing FreeRTOS documentation will not only help you, by *
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; * ensuring you get running as quickly as possible and with an *
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; * in-depth knowledge of how to use FreeRTOS, it will also help *
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; * the FreeRTOS project to continue with its mission of providing *
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; * professional grade, cross platform, de facto standard solutions *
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; * for microcontrollers - completely free of charge! *
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; * *
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; * >>> See http://www.FreeRTOS.org/Documentation for details. <<< *
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; * *
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; * Thank you for using FreeRTOS, and thank you for your support! *
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; * *
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; ***************************************************************************
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;
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;
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; This file is part of the FreeRTOS distribution.
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;
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; FreeRTOS is free software; you can redistribute it and/or modify it under
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; the terms of the GNU General Public License (version 2) as published by the
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; Free Software Foundation AND MODIFIED BY the FreeRTOS exception.
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; >>>NOTE<<< The modification to the GPL is included to allow you to
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; distribute a combined work that includes FreeRTOS without being obliged to
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; provide the source code for proprietary components outside of the FreeRTOS
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; kernel. FreeRTOS is distributed in the hope that it will be useful, but
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; WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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; or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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; more details. You should have received a copy of the GNU General Public
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; License and the FreeRTOS license exception along with FreeRTOS; if not it
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; can be viewed here: http://www.freertos.org/a00114.html and also obtained
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; by writing to Richard Barry, contact details for whom are available on the
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; FreeRTOS WEB site.
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;
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; 1 tab == 4 spaces!
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;
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; http://www.FreeRTOS.org - Documentation, latest information, license and
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; contact details.
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;
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; http://www.SafeRTOS.com - A version that is certified for use in safety
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; critical systems.
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;
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; http://www.OpenRTOS.com - Commercial support, development, porting,
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; licensing and training services.
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;*/
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INCLUDE portmacro.inc
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IMPORT vTaskSwitchContext
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IMPORT vTaskIncrementTick
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EXPORT vPortYieldProcessor
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EXPORT vPortStartFirstTask
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EXPORT vPreemptiveTick
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EXPORT vPortYield
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VICVECTADDR EQU 0xFFFFF030
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T0IR EQU 0xE0004000
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T0MATCHBIT EQU 0x00000001
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ARM
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AREA PORT_ASM, CODE, READONLY
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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; Starting the first task is done by just restoring the context
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; setup by pxPortInitialiseStack
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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vPortStartFirstTask
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PRESERVE8
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portRESTORE_CONTEXT
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vPortYield
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PRESERVE8
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SVC 0
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bx lr
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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; Interrupt service routine for the SWI interrupt. The vector table is
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; configured in the startup.s file.
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;
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; vPortYieldProcessor() is used to manually force a context switch. The
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; SWI interrupt is generated by a call to taskYIELD() or portYIELD().
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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vPortYieldProcessor
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PRESERVE8
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; Within an IRQ ISR the link register has an offset from the true return
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; address, but an SWI ISR does not. Add the offset manually so the same
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; ISR return code can be used in both cases.
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ADD LR, LR, #4
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; Perform the context switch.
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portSAVE_CONTEXT ; Save current task context
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LDR R0, =vTaskSwitchContext ; Get the address of the context switch function
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MOV LR, PC ; Store the return address
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BX R0 ; Call the contedxt switch function
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portRESTORE_CONTEXT ; restore the context of the selected task
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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; Interrupt service routine for preemptive scheduler tick timer
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; Only used if portUSE_PREEMPTION is set to 1 in portmacro.h
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;
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; Uses timer 0 of LPC21XX Family
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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vPreemptiveTick
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PRESERVE8
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portSAVE_CONTEXT ; Save the context of the current task.
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LDR R0, =vTaskIncrementTick ; Increment the tick count.
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MOV LR, PC ; This may make a delayed task ready
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BX R0 ; to run.
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LDR R0, =vTaskSwitchContext ; Find the highest priority task that
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MOV LR, PC ; is ready to run.
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BX R0
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MOV R0, #T0MATCHBIT ; Clear the timer event
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LDR R1, =T0IR
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STR R0, [R1]
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LDR R0, =VICVECTADDR ; Acknowledge the interrupt
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STR R0,[R0]
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portRESTORE_CONTEXT ; Restore the context of the highest
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; priority task that is ready to run.
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END
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