;/* ; FreeRTOS V6.0.3 - Copyright (C) 2010 Real Time Engineers Ltd. ; ; *************************************************************************** ; * * ; * If you are: * ; * * ; * + New to FreeRTOS, * ; * + Wanting to learn FreeRTOS or multitasking in general quickly * ; * + Looking for basic training, * ; * + Wanting to improve your FreeRTOS skills and productivity * ; * * ; * then take a look at the FreeRTOS eBook * ; * * ; * "Using the FreeRTOS Real Time Kernel - a Practical Guide" * ; * http://www.FreeRTOS.org/Documentation * ; * * ; * A pdf reference manual is also available. Both are usually delivered * ; * to your inbox within 20 minutes to two hours when purchased between 8am * ; * and 8pm GMT (although please allow up to 24 hours in case of * ; * exceptional circumstances). 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 exception 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. ;*/ IMPORT ulCriticalNesting ; IMPORT pxCurrentTCB ; MACRO portRESTORE_CONTEXT LDR R0, =pxCurrentTCB ; Set the LR to the task stack. The location was... LDR R0, [R0] ; ... stored in pxCurrentTCB LDR LR, [R0] LDR R0, =ulCriticalNesting ; The critical nesting depth is the first item on... LDMFD LR!, {R1} ; ...the stack. Load it into the ulCriticalNesting var. STR R1, [R0] ; LDMFD LR!, {R0} ; Get the SPSR from the stack. MSR SPSR_cxsf, R0 ; LDMFD LR, {R0-R14}^ ; Restore all system mode registers for the task. NOP ; LDR LR, [LR, #+60] ; Restore the return address ; And return - correcting the offset in the LR to obtain ... SUBS PC, LR, #4 ; ...the correct address. MEND ; /**********************************************************************/ MACRO portSAVE_CONTEXT STMDB SP!, {R0} ; Store R0 first as we need to use it. STMDB SP,{SP}^ ; Set R0 to point to the task stack pointer. NOP ; SUB SP, SP, #4 ; LDMIA SP!,{R0} ; STMDB R0!, {LR} ; Push the return address onto the stack. MOV LR, R0 ; Now we have saved LR we can use it instead of R0. LDMIA SP!, {R0} ; Pop R0 so we can save it onto the system mode stack. STMDB LR,{R0-LR}^ ; Push all the system mode registers onto the task stack. NOP ; SUB LR, LR, #60 ; MRS R0, SPSR ; Push the SPSR onto the task stack. STMDB LR!, {R0} ; LDR R0, =ulCriticalNesting ; LDR R0, [R0] ; STMDB LR!, {R0} ; LDR R0, =pxCurrentTCB ; Store the new top of stack for the task. LDR R1, [R0] ; STR LR, [R1] ; MEND END