;/* | |
; FreeRTOS V7.5.3 - Copyright (C) 2013 Real Time Engineers Ltd. | |
; All rights reserved | |
; | |
; | |
; *************************************************************************** | |
; * * | |
; * FreeRTOS tutorial books are available in pdf and paperback. * | |
; * Complete, revised, and edited pdf reference manuals are also * | |
; * available. * | |
; * * | |
; * Purchasing FreeRTOS documentation will not only help you, by * | |
; * ensuring you get running as quickly as possible and with an * | |
; * in-depth knowledge of how to use FreeRTOS, it will also help * | |
; * the FreeRTOS project to continue with its mission of providing * | |
; * professional grade, cross platform, de facto standard solutions * | |
; * for microcontrollers - completely free of charge! * | |
; * * | |
; * >>> See http://www.FreeRTOS.org/Documentation for details. <<< * | |
; * * | |
; * Thank you for using FreeRTOS, and thank you for your support! * | |
; * * | |
; *************************************************************************** | |
; | |
; | |
; This file is part of the FreeRTOS distribution. | |
; | |
; FreeRTOS is free software; you can redistribute it and/or modify it under | |
; the terms of the GNU General Public License (version 2) as published by the | |
; Free Software Foundation AND MODIFIED BY the FreeRTOS exception. | |
; >>>NOTE<<< The modification to the GPL is included to allow you to | |
; distribute a combined work that includes FreeRTOS without being obliged to | |
; provide the source code for proprietary components outside of the FreeRTOS | |
; kernel. FreeRTOS 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 and the FreeRTOS license exception along with FreeRTOS; if not it | |
; can be viewed here: http://www.freertos.org/a00114.html and also obtained | |
; by writing to Richard Barry, contact details for whom are available on the | |
; FreeRTOS WEB site. | |
; | |
; 1 tab == 4 spaces! | |
; | |
; http://www.FreeRTOS.org - Documentation, latest information, license and | |
; contact details. | |
; | |
; http://www.SafeRTOS.com - A version that is certified for use in safety | |
; critical systems. | |
; | |
; http://www.OpenRTOS.com - Commercial support, development, porting, | |
; licensing and training services. | |
;*/ | |
.text | |
.arm | |
.ref vTaskSwitchContext | |
.ref xTaskIncrementTick | |
.ref ulTaskHasFPUContext | |
.ref pxCurrentTCB | |
;/*-----------------------------------------------------------*/ | |
; | |
; Save Task Context | |
; | |
portSAVE_CONTEXT .macro | |
DSB | |
; Push R0 as we are going to use it | |
STMDB SP!, {R0} | |
; Set R0 to point to the task stack pointer. | |
STMDB SP,{SP}^ | |
SUB SP, SP, #4 | |
LDMIA SP!,{R0} | |
; Push the return address onto the stack. | |
STMDB R0!, {LR} | |
; Now LR has been saved, it can be used instead of R0. | |
MOV LR, R0 | |
; Pop R0 so it can be saved onto the task stack. | |
LDMIA SP!, {R0} | |
; Push all the system mode registers onto the task stack. | |
STMDB LR,{R0-LR}^ | |
SUB LR, LR, #60 | |
; Push the SPSR onto the task stack. | |
MRS R0, SPSR | |
STMDB LR!, {R0} | |
.if (__TI_VFP_SUPPORT__) | |
;Determine if the task maintains an FPU context. | |
LDR R0, ulFPUContextConst | |
LDR R0, [R0] | |
; Test the flag | |
CMP R0, #0 | |
; If the task is not using a floating point context then skip the | |
; saving of the FPU registers. | |
BEQ PC+3 | |
FSTMDBD LR!, {D0-D15} | |
FMRX R1, FPSCR | |
STMFD LR!, {R1} | |
; Save the flag | |
STMDB LR!, {R0} | |
.endif | |
; Store the new top of stack for the task. | |
LDR R0, pxCurrentTCBConst | |
LDR R0, [R0] | |
STR LR, [R0] | |
.endm | |
;/*-----------------------------------------------------------*/ | |
; | |
; Restore Task Context | |
; | |
portRESTORE_CONTEXT .macro | |
LDR R0, pxCurrentTCBConst | |
LDR R0, [R0] | |
LDR LR, [R0] | |
.if (__TI_VFP_SUPPORT__) | |
; The floating point context flag is the first thing on the stack. | |
LDR R0, ulFPUContextConst | |
LDMFD LR!, {R1} | |
STR R1, [R0] | |
; Test the flag | |
CMP R1, #0 | |
; If the task is not using a floating point context then skip the | |
; VFP register loads. | |
BEQ PC+3 | |
; Restore the floating point context. | |
LDMFD LR!, {R0} | |
FLDMIAD LR!, {D0-D15} | |
FMXR FPSCR, R0 | |
.endif | |
; Get the SPSR from the stack. | |
LDMFD LR!, {R0} | |
MSR SPSR_CSXF, R0 | |
; Restore all system mode registers for the task. | |
LDMFD LR, {R0-R14}^ | |
; Restore the return address. | |
LDR LR, [LR, #+60] | |
; And return - correcting the offset in the LR to obtain the | |
; correct address. | |
SUBS PC, LR, #4 | |
.endm | |
;/*-----------------------------------------------------------*/ | |
; Start the first task by restoring its context. | |
.def vPortStartFirstTask | |
vPortStartFirstTask: | |
portRESTORE_CONTEXT | |
;/*-----------------------------------------------------------*/ | |
; Yield to another task. | |
.def vPortYieldProcessor | |
vPortYieldProcessor: | |
; Within an IRQ ISR the link register has an offset from the true return | |
; address. SWI doesn't do this. Add the offset manually so the ISR | |
; return code can be used. | |
ADD LR, LR, #4 | |
; First save the context of the current task. | |
portSAVE_CONTEXT | |
; Select the next task to execute. */ | |
BL vTaskSwitchContext | |
; Restore the context of the task selected to execute. | |
portRESTORE_CONTEXT | |
;/*-----------------------------------------------------------*/ | |
; Yield to another task from within the FreeRTOS API | |
.def vPortYeildWithinAPI | |
vPortYeildWithinAPI: | |
; Save the context of the current task. | |
portSAVE_CONTEXT | |
; Clear SSI flag. | |
MOVW R0, #0xFFF4 | |
MOVT R0, #0xFFFF | |
LDR R0, [R0] | |
; Select the next task to execute. */ | |
BL vTaskSwitchContext | |
; Restore the context of the task selected to execute. | |
portRESTORE_CONTEXT | |
;/*-----------------------------------------------------------*/ | |
; Preemptive Tick | |
.def vPortPreemptiveTick | |
vPortPreemptiveTick: | |
; Save the context of the current task. | |
portSAVE_CONTEXT | |
; Clear interrupt flag | |
MOVW R0, #0xFC88 | |
MOVT R0, #0xFFFF | |
MOV R1, #1 | |
STR R1, [R0] | |
; Increment the tick count, making any adjustments to the blocked lists | |
; that may be necessary. | |
BL xTaskIncrementTick | |
; Select the next task to execute. | |
CMP R0, #0 | |
BLNE vTaskSwitchContext | |
; Restore the context of the task selected to execute. | |
portRESTORE_CONTEXT | |
;------------------------------------------------------------------------------- | |
.if (__TI_VFP_SUPPORT__) | |
.def vPortInitialiseFPSCR | |
vPortInitialiseFPSCR: | |
MOV R0, #0 | |
FMXR FPSCR, R0 | |
BX LR | |
.endif ;__TI_VFP_SUPPORT__ | |
pxCurrentTCBConst .word pxCurrentTCB | |
ulFPUContextConst .word ulTaskHasFPUContext | |
;------------------------------------------------------------------------------- | |