/* | |
FreeRTOS V6.0.2 - 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. | |
*/ | |
typedef void tskTCB; | |
extern volatile tskTCB * volatile pxCurrentTCB; | |
extern void vTaskSwitchContext( void ); | |
/* | |
* Saves the stack pointer for one task into its TCB, calls | |
* vTaskSwitchContext() to update the TCB being used, then restores the stack | |
* from the new TCB read to run the task. | |
*/ | |
void portSWITCH_CONTEXT( void ); | |
/* | |
* Load the stack pointer from the TCB of the task which is going to be first | |
* to execute. Then force an IRET so the registers and IP are popped off the | |
* stack. | |
*/ | |
void portFIRST_CONTEXT( void ); | |
/* There are slightly different versions depending on whether you are building | |
to include debugger information. If debugger information is used then there | |
are a couple of extra bytes left of the ISR stack (presumably for use by the | |
debugger). The true stack pointer is then stored in the bp register. We add | |
2 to the stack pointer to remove the extra bytes before we restore our context. */ | |
#ifdef DEBUG_BUILD | |
#pragma aux portSWITCH_CONTEXT = "mov ax, seg pxCurrentTCB" \ | |
"mov ds, ax" \ | |
"les bx, pxCurrentTCB" /* Save the stack pointer into the TCB. */ \ | |
"mov es:0x2[ bx ], ss" \ | |
"mov es:[ bx ], sp" \ | |
"call vTaskSwitchContext" /* Perform the switch. */ \ | |
"mov ax, seg pxCurrentTCB" /* Restore the stack pointer from the TCB. */ \ | |
"mov ds, ax" \ | |
"les bx, dword ptr pxCurrentTCB" \ | |
"mov ss, es:[ bx + 2 ]" \ | |
"mov sp, es:[ bx ]" \ | |
"mov bp, sp" /* Prepair the bp register for the restoration of the SP in the compiler generated portion of the ISR */ \ | |
"add bp, 0x0002" | |
#pragma aux portFIRST_CONTEXT = "mov ax, seg pxCurrentTCB" \ | |
"mov ds, ax" \ | |
"les bx, dword ptr pxCurrentTCB" \ | |
"mov ss, es:[ bx + 2 ]" \ | |
"mov sp, es:[ bx ]" \ | |
"add sp, 0x0002" /* Remove the extra bytes that exist in debug builds before restoring the context. */ \ | |
"pop ax" \ | |
"pop ax" \ | |
"pop es" \ | |
"pop ds" \ | |
"popa" \ | |
"iret" | |
#else | |
#pragma aux portSWITCH_CONTEXT = "mov ax, seg pxCurrentTCB" \ | |
"mov ds, ax" \ | |
"les bx, pxCurrentTCB" /* Save the stack pointer into the TCB. */ \ | |
"mov es:0x2[ bx ], ss" \ | |
"mov es:[ bx ], sp" \ | |
"call vTaskSwitchContext" /* Perform the switch. */ \ | |
"mov ax, seg pxCurrentTCB" /* Restore the stack pointer from the TCB. */ \ | |
"mov ds, ax" \ | |
"les bx, dword ptr pxCurrentTCB" \ | |
"mov ss, es:[ bx + 2 ]" \ | |
"mov sp, es:[ bx ]" | |
#pragma aux portFIRST_CONTEXT = "mov ax, seg pxCurrentTCB" \ | |
"mov ds, ax" \ | |
"les bx, dword ptr pxCurrentTCB" \ | |
"mov ss, es:[ bx + 2 ]" \ | |
"mov sp, es:[ bx ]" \ | |
"pop ax" \ | |
"pop ax" \ | |
"pop es" \ | |
"pop ds" \ | |
"popa" \ | |
"iret" | |
#endif | |