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Update to MIT licensed FreeRTOS V10.0.0 - see https://www.freertos.org/History.txt
[freertos] / FreeRTOS / Source / portable / oWatcom / 16BitDOS / common / portasm.h
1 /*\r
2  * FreeRTOS Kernel V10.0.0\r
3  * Copyright (C) 2017 Amazon.com, Inc. or its affiliates.  All Rights Reserved.\r
4  *\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
11  *\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
15  *\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
22  *\r
23  * http://www.FreeRTOS.org\r
24  * http://aws.amazon.com/freertos\r
25  *\r
26  * 1 tab == 4 spaces!\r
27  */\r
28 \r
29 typedef void TCB_t;\r
30 extern volatile TCB_t * volatile pxCurrentTCB;\r
31 extern void vTaskSwitchContext( void );\r
32 \r
33 /* \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
37  */\r
38 void portSWITCH_CONTEXT( void );\r
39 \r
40 /*\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
43  * stack.\r
44  */\r
45 void portFIRST_CONTEXT( void );\r
46 \r
47 /* There are slightly different versions depending on whether you are building\r
48 to include debugger information.  If debugger information is used then there\r
49 are a couple of extra bytes left of the ISR stack (presumably for use by the\r
50 debugger).  The true stack pointer is then stored in the bp register.  We add\r
51 2 to the stack pointer to remove the extra bytes before we restore our context. */\r
52 \r
53 #ifdef DEBUG_BUILD\r
54 \r
55         #pragma aux portSWITCH_CONTEXT =        "mov    ax, seg pxCurrentTCB"                                                                                                           \\r
56                                                                                 "mov    ds, ax"                                                                                                                                         \\r
57                                                                                 "les    bx, pxCurrentTCB"                       /* Save the stack pointer into the TCB. */              \\r
58                                                                                 "mov    es:0x2[ bx ], ss"                                                                                                                       \\r
59                                                                                 "mov    es:[ bx ], sp"                                                                                                                          \\r
60                                                                                 "call   vTaskSwitchContext"                     /* Perform the switch. */                                               \\r
61                                                                                 "mov    ax, seg pxCurrentTCB"           /* Restore the stack pointer from the TCB. */   \\r
62                                                                                 "mov    ds, ax"                                                                                                                                         \\r
63                                                                                 "les    bx, dword ptr pxCurrentTCB"                                                                                                     \\r
64                                                                                 "mov    ss, es:[ bx + 2 ]"                                                                                                                      \\r
65                                                                                 "mov    sp, es:[ bx ]"                                                                                                                          \\r
66                                                                                 "mov    bp, sp"                                         /* Prepair the bp register for the restoration of the SP in the compiler generated portion of the ISR */        \\r
67                                                                                 "add    bp, 0x0002"\r
68 \r
69                                                                                 \r
70 \r
71         #pragma aux portFIRST_CONTEXT =         "mov    ax, seg pxCurrentTCB"                   \\r
72                                                                                 "mov    ds, ax"                                                 \\r
73                                                                                 "les    bx, dword ptr pxCurrentTCB"             \\r
74                                                                                 "mov    ss, es:[ bx + 2 ]"                              \\r
75                                                                                 "mov    sp, es:[ bx ]"                                  \\r
76                                                                                 "add    sp, 0x0002"                                             /* Remove the extra bytes that exist in debug builds before restoring the context. */ \\r
77                                                                                 "pop    ax"                                                             \\r
78                                                                                 "pop    ax"                                                             \\r
79                                                                                 "pop    es"                                                             \\r
80                                                                                 "pop    ds"                                                             \\r
81                                                                                 "popa"                                                                  \\r
82                                                                                 "iret"                                                                  \r
83 #else\r
84 \r
85         #pragma aux portSWITCH_CONTEXT =        "mov    ax, seg pxCurrentTCB"                                                                                                           \\r
86                                                                                 "mov    ds, ax"                                                                                                                                         \\r
87                                                                                 "les    bx, pxCurrentTCB"                       /* Save the stack pointer into the TCB. */              \\r
88                                                                                 "mov    es:0x2[ bx ], ss"                                                                                                                       \\r
89                                                                                 "mov    es:[ bx ], sp"                                                                                                                          \\r
90                                                                                 "call   vTaskSwitchContext"                     /* Perform the switch. */                                               \\r
91                                                                                 "mov    ax, seg pxCurrentTCB"           /* Restore the stack pointer from the TCB. */   \\r
92                                                                                 "mov    ds, ax"                                                                                                                                         \\r
93                                                                                 "les    bx, dword ptr pxCurrentTCB"                                                                                                     \\r
94                                                                                 "mov    ss, es:[ bx + 2 ]"                                                                                                                      \\r
95                                                                                 "mov    sp, es:[ bx ]"\r
96                                                                                 \r
97 \r
98         #pragma aux portFIRST_CONTEXT =         "mov    ax, seg pxCurrentTCB"                   \\r
99                                                                                 "mov    ds, ax"                                                 \\r
100                                                                                 "les    bx, dword ptr pxCurrentTCB"             \\r
101                                                                                 "mov    ss, es:[ bx + 2 ]"                              \\r
102                                                                                 "mov    sp, es:[ bx ]"                                  \\r
103                                                                                 "pop    ax"                                                             \\r
104                                                                                 "pop    ax"                                                             \\r
105                                                                                 "pop    es"                                                             \\r
106                                                                                 "pop    ds"                                                             \\r
107                                                                                 "popa"                                                                  \\r
108                                                                                 "iret"                                                                  \r
109 #endif\r
110 \r
111 \r