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[/] [openrisc/] [trunk/] [rtos/] [freertos-6.1.1/] [Source/] [portable/] [RVDS/] [ARM7_LPC21xx/] [portASM.s] - Blame information for rev 664

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1 572 jeremybenn
;/*
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;    FreeRTOS V6.1.1 - Copyright (C) 2011 Real Time Engineers Ltd.
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;
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;    ***************************************************************************
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;    *                                                                         *
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;    * If you are:                                                             *
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;    *                                                                         *
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;    *    + New to FreeRTOS,                                                   *
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;    *    + Wanting to learn FreeRTOS or multitasking in general quickly       *
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;    *    + Looking for basic training,                                        *
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;    *    + Wanting to improve your FreeRTOS skills and productivity           *
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;    *                                                                         *
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;    * then take a look at the FreeRTOS books - available as PDF or paperback  *
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;    *                                                                         *
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;    *        "Using the FreeRTOS Real Time Kernel - a Practical Guide"        *
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;    *                  http://www.FreeRTOS.org/Documentation                  *
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;    *                                                                         *
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;    * A pdf reference manual is also available.  Both are usually delivered   *
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;    * to your inbox within 20 minutes to two hours when purchased between 8am *
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;    * and 8pm GMT (although please allow up to 24 hours in case of            *
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;    * exceptional circumstances).  Thank you for your support!                *
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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 exception to the GPL is included to allow you to distribute
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;    a combined work that includes FreeRTOS without being obliged to provide the
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;    source code for proprietary components outside of the FreeRTOS kernel.
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;    FreeRTOS is distributed in the hope that it will be useful, but WITHOUT
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;    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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;    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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