2 * FreeRTOS Kernel V10.1.0
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3 * Copyright (C) 2017 Amazon.com, Inc. or its affiliates. All Rights Reserved.
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5 * Permission is hereby granted, free of charge, to any person obtaining a copy of
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6 * this software and associated documentation files (the "Software"), to deal in
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7 * the Software without restriction, including without limitation the rights to
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8 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
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9 * the Software, and to permit persons to whom the Software is furnished to do so,
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10 * subject to the following conditions:
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12 * The above copyright notice and this permission notice shall be included in all
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13 * copies or substantial portions of the Software.
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15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
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17 * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
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18 * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
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19 * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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20 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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22 * http://www.FreeRTOS.org
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23 * http://aws.amazon.com/freertos
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25 * 1 tab == 4 spaces!
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32 extern volatile TCB_t * volatile pxCurrentTCB;
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33 extern void vTaskSwitchContext( void );
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36 * Saves the stack pointer for one task into its TCB, calls
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37 * vTaskSwitchContext() to update the TCB being used, then restores the stack
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38 * from the new TCB read to run the task.
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40 void portSWITCH_CONTEXT( void );
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43 * Load the stack pointer from the TCB of the task which is going to be first
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44 * to execute. Then force an IRET so the registers and IP are popped off the
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47 void portFIRST_CONTEXT( void );
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49 /* There are slightly different versions depending on whether you are building
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50 to include debugger information. If debugger information is used then there
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51 are a couple of extra bytes left of the ISR stack (presumably for use by the
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52 debugger). The true stack pointer is then stored in the bp register. We add
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53 2 to the stack pointer to remove the extra bytes before we restore our context. */
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55 #define portSWITCH_CONTEXT() \
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56 asm { mov ax, seg pxCurrentTCB } \
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57 asm { mov ds, ax } \
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58 asm { les bx, pxCurrentTCB } /* Save the stack pointer into the TCB. */ \
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59 asm { mov es:0x2[ bx ], ss } \
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60 asm { mov es:[ bx ], sp } \
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61 asm { call far ptr vTaskSwitchContext } /* Perform the switch. */ \
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62 asm { mov ax, seg pxCurrentTCB } /* Restore the stack pointer from the TCB. */ \
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63 asm { mov ds, ax } \
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64 asm { les bx, dword ptr pxCurrentTCB } \
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65 asm { mov ss, es:[ bx + 2 ] } \
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66 asm { mov sp, es:[ bx ] }
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68 #define portFIRST_CONTEXT() \
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69 __asm { mov ax, seg pxCurrentTCB } \
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70 __asm { mov ds, ax } \
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71 __asm { les bx, dword ptr pxCurrentTCB } \
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72 __asm { mov ss, es:[ bx + 2 ] } \
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73 __asm { mov sp, es:[ bx ] } \
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projects / freertos / blob