2 * FreeRTOS Kernel V10.0.0
\r
3 * Copyright (C) 2017 Amazon.com, Inc. or its affiliates. All Rights Reserved.
\r
5 * Permission is hereby granted, free of charge, to any person obtaining a copy of
\r
6 * this software and associated documentation files (the "Software"), to deal in
\r
7 * the Software without restriction, including without limitation the rights to
\r
8 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
\r
9 * the Software, and to permit persons to whom the Software is furnished to do so,
\r
10 * subject to the following conditions:
\r
12 * The above copyright notice and this permission notice shall be included in all
\r
13 * copies or substantial portions of the Software. If you wish to use our Amazon
\r
14 * FreeRTOS name, please do so in a fair use way that does not cause confusion.
\r
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
\r
17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
\r
18 * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
\r
19 * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
\r
20 * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
\r
21 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
\r
23 * http://www.FreeRTOS.org
\r
24 * http://aws.amazon.com/freertos
\r
26 * 1 tab == 4 spaces!
\r
30 extern volatile TCB_t * volatile pxCurrentTCB;
\r
31 extern void vTaskSwitchContext( void );
\r
34 * Saves the stack pointer for one task into its TCB, calls
\r
35 * vTaskSwitchContext() to update the TCB being used, then restores the stack
\r
36 * from the new TCB read to run the task.
\r
38 void portSWITCH_CONTEXT( void );
\r
41 * Load the stack pointer from the TCB of the task which is going to be first
\r
42 * to execute. Then force an IRET so the registers and IP are popped off the
\r
45 void portFIRST_CONTEXT( void );
\r
47 #define portSWITCH_CONTEXT() \
\r
48 asm { mov ax, seg pxCurrentTCB } \
\r
49 asm { mov ds, ax } \
\r
50 asm { les bx, pxCurrentTCB } /* Save the stack pointer into the TCB. */ \
\r
51 asm { mov es:0x2[ bx ], ss } \
\r
52 asm { mov es:[ bx ], sp } \
\r
53 asm { call far ptr vTaskSwitchContext } /* Perform the switch. */ \
\r
54 asm { mov ax, seg pxCurrentTCB } /* Restore the stack pointer from the TCB. */ \
\r
55 asm { mov ds, ax } \
\r
56 asm { les bx, dword ptr pxCurrentTCB } \
\r
57 asm { mov ss, es:[ bx + 2 ] } \
\r
58 asm { mov sp, es:[ bx ] }
\r
60 #define portFIRST_CONTEXT() \
\r
61 asm { mov ax, seg pxCurrentTCB } \
\r
62 asm { mov ds, ax } \
\r
63 asm { les bx, dword ptr pxCurrentTCB } \
\r
64 asm { mov ss, es:[ bx + 2 ] } \
\r
65 asm { mov sp, es:[ bx ] } \
\r