;/* ; FreeRTOS V8.0.0 - Copyright (C) 2014 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 ;-------------------------------------------------------------------------------