/* FreeRTOS V7.3.0 - Copyright (C) 2012 Real Time Engineers Ltd. FEATURES AND PORTS ARE ADDED TO FREERTOS ALL THE TIME. PLEASE VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION. *************************************************************************** * * * 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! *************************************************************************** * * * Having a problem? Start by reading the FAQ "My application does * * not run, what could be wrong?" * * * * http://www.FreeRTOS.org/FAQHelp.html * * * *************************************************************************** http://www.FreeRTOS.org - Documentation, training, latest versions, license and contact details. http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products, including FreeRTOS+Trace - an indispensable productivity tool. Real Time Engineers ltd license FreeRTOS to High Integrity Systems, who sell the code with commercial support, indemnification, and middleware, under the OpenRTOS brand: http://www.OpenRTOS.com. High Integrity Systems also provide a safety engineered and independently SIL3 certified version under the SafeRTOS brand: http://www.SafeRTOS.com. */ /* Changes from V1.00: + pxPortInitialiseStack() now initialises the stack of new tasks to the same format used by the compiler. This allows the compiler generated interrupt mechanism to be used for context switches. Changes from V2.4.2: + pvPortMalloc and vPortFree have been removed. The projects now use the definitions from the source/portable/MemMang directory. Changes from V2.6.1: + usPortCheckFreeStackSpace() has been moved to tasks.c. */ #include #include "FreeRTOS.h" /*-----------------------------------------------------------*/ /* See header file for description. */ portSTACK_TYPE *pxPortInitialiseStack( portSTACK_TYPE *pxTopOfStack, pdTASK_CODE pxCode, void *pvParameters ) { portSTACK_TYPE DS_Reg = 0, *pxOriginalSP; /* Place a few bytes of known values on the bottom of the stack. This is just useful for debugging. */ *pxTopOfStack = 0x1111; pxTopOfStack--; *pxTopOfStack = 0x2222; pxTopOfStack--; *pxTopOfStack = 0x3333; pxTopOfStack--; *pxTopOfStack = 0x4444; pxTopOfStack--; *pxTopOfStack = 0x5555; pxTopOfStack--; /*lint -e950 -e611 -e923 Lint doesn't like this much - but nothing I can do about it. */ /* We are going to start the scheduler using a return from interrupt instruction to load the program counter, so first there would be the status register and interrupt return address. We make this the start of the task. */ *pxTopOfStack = portINITIAL_SW; pxTopOfStack--; *pxTopOfStack = FP_SEG( pxCode ); pxTopOfStack--; *pxTopOfStack = FP_OFF( pxCode ); pxTopOfStack--; /* We are going to setup the stack for the new task to look like the stack frame was setup by a compiler generated ISR. We need to know the address of the existing stack top to place in the SP register within the stack frame. pxOriginalSP holds SP before (simulated) pusha was called. */ pxOriginalSP = pxTopOfStack; /* The remaining registers would be pushed on the stack by our context switch function. These are loaded with values simply to make debugging easier. */ *pxTopOfStack = FP_OFF( pvParameters ); /* AX */ pxTopOfStack--; *pxTopOfStack = ( portSTACK_TYPE ) 0xCCCC; /* CX */ pxTopOfStack--; *pxTopOfStack = FP_SEG( pvParameters ); /* DX */ pxTopOfStack--; *pxTopOfStack = ( portSTACK_TYPE ) 0xBBBB; /* BX */ pxTopOfStack--; *pxTopOfStack = FP_OFF( pxOriginalSP ); /* SP */ pxTopOfStack--; *pxTopOfStack = ( portSTACK_TYPE ) 0xBBBB; /* BP */ pxTopOfStack--; *pxTopOfStack = ( portSTACK_TYPE ) 0x0123; /* SI */ pxTopOfStack--; *pxTopOfStack = ( portSTACK_TYPE ) 0xDDDD; /* DI */ /* We need the true data segment. */ __asm{ MOV DS_Reg, DS }; pxTopOfStack--; *pxTopOfStack = DS_Reg; /* DS */ pxTopOfStack--; *pxTopOfStack = ( portSTACK_TYPE ) 0xEEEE; /* ES */ /* The AX register is pushed again twice - don't know why. */ pxTopOfStack--; *pxTopOfStack = FP_OFF( pvParameters ); /* AX */ pxTopOfStack--; *pxTopOfStack = FP_OFF( pvParameters ); /* AX */ #ifdef DEBUG_BUILD /* The compiler adds space to each ISR stack if building to include debug information. Presumably this is used by the debugger - we don't need to initialise it to anything just make sure it is there. */ pxTopOfStack--; #endif /*lint +e950 +e611 +e923 */ return pxTopOfStack; } /*-----------------------------------------------------------*/