2 FreeRTOS.org V4.3.0 - Copyright (C) 2003-2007 Richard Barry.
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4 This file is part of the FreeRTOS.org distribution.
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6 FreeRTOS.org is free software; you can redistribute it and/or modify
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7 it under the terms of the GNU General Public License as published by
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8 the Free Software Foundation; either version 2 of the License, or
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9 (at your option) any later version.
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11 FreeRTOS.org is distributed in the hope that it will be useful,
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12 but WITHOUT ANY WARRANTY; without even the implied warranty of
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13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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14 GNU General Public License for more details.
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16 You should have received a copy of the GNU General Public License
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17 along with FreeRTOS.org; if not, write to the Free Software
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18 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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20 A special exception to the GPL can be applied should you wish to distribute
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21 a combined work that includes FreeRTOS.org, without being obliged to provide
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22 the source code for any proprietary components. See the licensing section
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23 of http://www.FreeRTOS.org for full details of how and when the exception
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26 ***************************************************************************
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27 See http://www.FreeRTOS.org for documentation, latest information, license
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28 and contact details. Please ensure to read the configuration and relevant
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29 port sections of the online documentation.
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31 Also see http://www.SafeRTOS.com for an IEC 61508 compliant version along
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32 with commercial development and support options.
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33 ***************************************************************************
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39 typedef void tskTCB;
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40 extern volatile tskTCB * volatile pxCurrentTCB;
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41 extern void vTaskSwitchContext( void );
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44 * Saves the stack pointer for one task into its TCB, calls
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45 * vTaskSwitchContext() to update the TCB being used, then restores the stack
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46 * from the new TCB read to run the task.
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48 void portSWITCH_CONTEXT( void );
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51 * Load the stack pointer from the TCB of the task which is going to be first
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52 * to execute. Then force an IRET so the registers and IP are popped off the
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55 void portFIRST_CONTEXT( void );
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57 /* There are slightly different versions depending on whether you are building
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58 to include debugger information. If debugger information is used then there
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59 are a couple of extra bytes left of the ISR stack (presumably for use by the
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60 debugger). The true stack pointer is then stored in the bp register. We add
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61 2 to the stack pointer to remove the extra bytes before we restore our context. */
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63 #define portSWITCH_CONTEXT() \
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64 asm { mov ax, seg pxCurrentTCB } \
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65 asm { mov ds, ax } \
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66 asm { les bx, pxCurrentTCB } /* Save the stack pointer into the TCB. */ \
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67 asm { mov es:0x2[ bx ], ss } \
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68 asm { mov es:[ bx ], sp } \
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69 asm { call far ptr vTaskSwitchContext } /* Perform the switch. */ \
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70 asm { mov ax, seg pxCurrentTCB } /* Restore the stack pointer from the TCB. */ \
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71 asm { mov ds, ax } \
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72 asm { les bx, dword ptr pxCurrentTCB } \
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73 asm { mov ss, es:[ bx + 2 ] } \
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74 asm { mov sp, es:[ bx ] }
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76 #define portFIRST_CONTEXT() \
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77 __asm { mov ax, seg pxCurrentTCB } \
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78 __asm { mov ds, ax } \
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79 __asm { les bx, dword ptr pxCurrentTCB } \
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80 __asm { mov ss, es:[ bx + 2 ] } \
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81 __asm { mov sp, es:[ bx ] } \
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projects / freertos / blob