;/* | |
; FreeRTOS.org V5.1.0 - Copyright (C) 2003-2008 Richard Barry. | |
; | |
; This file is part of the FreeRTOS.org distribution. | |
; | |
; FreeRTOS.org is free software; you can redistribute it and/or modify | |
; it under the terms of the GNU General Public License as published by | |
; the Free Software Foundation; either version 2 of the License, or | |
; (at your option) any later version. | |
; | |
; FreeRTOS.org is distributed in the hope that it will be useful, | |
; but WITHOUT ANY WARRANTY; without even the implied warranty of | |
; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
; GNU General Public License for more details. | |
; | |
; You should have received a copy of the GNU General Public License | |
; along with FreeRTOS.org; if not, write to the Free Software | |
; Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA | |
; | |
; A special exception to the GPL can be applied should you wish to distribute | |
; a combined work that includes FreeRTOS.org, without being obliged to provide | |
; the source code for any proprietary components. See the licensing section | |
; of http://www.FreeRTOS.org for full details of how and when the exception | |
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; | |
; *************************************************************************** | |
; *************************************************************************** | |
; * * | |
; * SAVE TIME AND MONEY! We can port FreeRTOS.org to your own hardware, * | |
; * and even write all or part of your application on your behalf. * | |
; * See http://www.OpenRTOS.com for details of the services we provide to * | |
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; *************************************************************************** | |
; *************************************************************************** | |
; | |
; Please ensure to read the configuration and relevant port sections of the | |
; online documentation. | |
; | |
; http://www.FreeRTOS.org - Documentation, latest information, license and | |
; contact details. | |
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;*/ | |
INCLUDE portmacro.inc | |
IMPORT vTaskSwitchContext | |
IMPORT vTaskIncrementTick | |
EXPORT vPortYieldProcessor | |
EXPORT vPortStartFirstTask | |
EXPORT vPreemptiveTick | |
EXPORT vPortYield | |
VICVECTADDR EQU 0xFFFFF030 | |
T0IR EQU 0xE0004000 | |
T0MATCHBIT EQU 0x00000001 | |
ARM | |
AREA PORT_ASM, CODE, READONLY | |
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; | |
; Starting the first task is done by just restoring the context | |
; setup by pxPortInitialiseStack | |
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; | |
vPortStartFirstTask | |
PRESERVE8 | |
portRESTORE_CONTEXT | |
vPortYield | |
PRESERVE8 | |
SVC 0 | |
bx lr | |
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; | |
; Interrupt service routine for the SWI interrupt. The vector table is | |
; configured in the startup.s file. | |
; | |
; vPortYieldProcessor() is used to manually force a context switch. The | |
; SWI interrupt is generated by a call to taskYIELD() or portYIELD(). | |
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; | |
vPortYieldProcessor | |
PRESERVE8 | |
; Within an IRQ ISR the link register has an offset from the true return | |
; address, but an SWI ISR does not. Add the offset manually so the same | |
; ISR return code can be used in both cases. | |
ADD LR, LR, #4 | |
; Perform the context switch. | |
portSAVE_CONTEXT ; Save current task context | |
LDR R0, =vTaskSwitchContext ; Get the address of the context switch function | |
MOV LR, PC ; Store the return address | |
BX R0 ; Call the contedxt switch function | |
portRESTORE_CONTEXT ; restore the context of the selected task | |
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; | |
; Interrupt service routine for preemptive scheduler tick timer | |
; Only used if portUSE_PREEMPTION is set to 1 in portmacro.h | |
; | |
; Uses timer 0 of LPC21XX Family | |
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; | |
vPreemptiveTick | |
PRESERVE8 | |
portSAVE_CONTEXT ; Save the context of the current task. | |
LDR R0, =vTaskIncrementTick ; Increment the tick count. | |
MOV LR, PC ; This may make a delayed task ready | |
BX R0 ; to run. | |
LDR R0, =vTaskSwitchContext ; Find the highest priority task that | |
MOV LR, PC ; is ready to run. | |
BX R0 | |
MOV R0, #T0MATCHBIT ; Clear the timer event | |
LDR R1, =T0IR | |
STR R0, [R1] | |
LDR R0, =VICVECTADDR ; Acknowledge the interrupt | |
STR R0,[R0] | |
portRESTORE_CONTEXT ; Restore the context of the highest | |
; priority task that is ready to run. | |
END | |