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88 lines
3.6 KiB
C
88 lines
3.6 KiB
C
19 years ago
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/*
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FreeRTOS V4.0.1 - Copyright (C) 2003-2006 Richard Barry.
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This file is part of the FreeRTOS distribution.
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FreeRTOS is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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FreeRTOS is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with FreeRTOS; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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A special exception to the GPL can be applied should you wish to distribute
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a combined work that includes FreeRTOS, without being obliged to provide
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the source code for any proprietary components. See the licensing section
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of http://www.FreeRTOS.org for full details of how and when the exception
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can be applied.
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***************************************************************************
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See http://www.FreeRTOS.org for documentation, latest information, license
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and contact details. Please ensure to read the configuration and relevant
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port sections of the online documentation.
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***************************************************************************
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*/
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typedef void tskTCB;
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extern volatile tskTCB * volatile pxCurrentTCB;
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extern void vTaskSwitchContext( void );
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/*
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* Saves the stack pointer for one task into its TCB, calls
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* vTaskSwitchContext() to update the TCB being used, then restores the stack
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* from the new TCB read to run the task.
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*/
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void portSWITCH_CONTEXT( void );
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/*
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* Load the stack pointer from the TCB of the task which is going to be first
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* to execute. Then force an IRET so the registers and IP are popped off the
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* stack.
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*/
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void portFIRST_CONTEXT( void );
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/* There are slightly different versions depending on whether you are building
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to include debugger information. If debugger information is used then there
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are a couple of extra bytes left of the ISR stack (presumably for use by the
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debugger). The true stack pointer is then stored in the bp register. We add
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2 to the stack pointer to remove the extra bytes before we restore our context. */
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#define portSWITCH_CONTEXT() \
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asm { mov ax, seg pxCurrentTCB } \
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asm { mov ds, ax } \
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asm { les bx, pxCurrentTCB } /* Save the stack pointer into the TCB. */ \
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asm { mov es:0x2[ bx ], ss } \
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asm { mov es:[ bx ], sp } \
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asm { call far ptr vTaskSwitchContext } /* Perform the switch. */ \
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asm { mov ax, seg pxCurrentTCB } /* Restore the stack pointer from the TCB. */ \
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asm { mov ds, ax } \
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asm { les bx, dword ptr pxCurrentTCB } \
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asm { mov ss, es:[ bx + 2 ] } \
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asm { mov sp, es:[ bx ] }
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#define portFIRST_CONTEXT() \
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__asm { mov ax, seg pxCurrentTCB } \
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__asm { mov ds, ax } \
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__asm { les bx, dword ptr pxCurrentTCB } \
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__asm { mov ss, es:[ bx + 2 ] } \
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__asm { mov sp, es:[ bx ] } \
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__asm { pop bx } \
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__asm { pop di } \
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__asm { pop si } \
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__asm { pop ds } \
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__asm { pop es } \
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__asm { pop dx } \
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__asm { pop cx } \
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__asm { pop bx } \
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__asm { pop ax } \
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__asm { iret }
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