begriffs open source - cmsis-freertos/blob - Source/portable/oWatcom/16BitDOS/common/portasm.h

   1 /*
   2  * FreeRTOS Kernel V11.2.0
   3  * Copyright (C) 2021 Amazon.com, Inc. or its affiliates. All Rights Reserved.
   4  *
   5  * SPDX-License-Identifier: MIT
   6  *
   7  * Permission is hereby granted, free of charge, to any person obtaining a copy of
   8  * this software and associated documentation files (the "Software"), to deal in
   9  * the Software without restriction, including without limitation the rights to
  10  * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
  11  * the Software, and to permit persons to whom the Software is furnished to do so,
  12  * subject to the following conditions:
  13  *
  14  * The above copyright notice and this permission notice shall be included in all
  15  * copies or substantial portions of the Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  18  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
  19  * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
  20  * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
  21  * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  22  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  23  *
  24  * https://www.FreeRTOS.org
  25  * https://github.com/FreeRTOS
  26  *
  27  */
  28
  29 typedef void TCB_t;
  30 extern volatile TCB_t * volatile pxCurrentTCB;
  31 extern void vTaskSwitchContext( void );
  32
  33 /*
  34  * Saves the stack pointer for one task into its TCB, calls
  35  * vTaskSwitchContext() to update the TCB being used, then restores the stack
  36  * from the new TCB read to run the task.
  37  */
  38 void portSWITCH_CONTEXT( void );
  39
  40 /*
  41  * Load the stack pointer from the TCB of the task which is going to be first
  42  * to execute.  Then force an IRET so the registers and IP are popped off the
  43  * stack.
  44  */
  45 void portFIRST_CONTEXT( void );
  46
  47 /* There are slightly different versions depending on whether you are building
  48 to include debugger information.  If debugger information is used then there
  49 are a couple of extra bytes left of the ISR stack (presumably for use by the
  50 debugger).  The true stack pointer is then stored in the bp register.  We add
  51 2 to the stack pointer to remove the extra bytes before we restore our context. */
  52
  53 #ifdef DEBUG_BUILD
  54
  55     #pragma aux portSWITCH_CONTEXT =    "mov    ax, seg pxCurrentTCB"                                                       \
  56                                         "mov    ds, ax"                                                                     \
  57                                         "les    bx, pxCurrentTCB"           /* Save the stack pointer into the TCB. */      \
  58                                         "mov    es:0x2[ bx ], ss"                                                           \
  59                                         "mov    es:[ bx ], sp"                                                              \
  60                                         "call   vTaskSwitchContext"         /* Perform the switch. */                       \
  61                                         "mov    ax, seg pxCurrentTCB"       /* Restore the stack pointer from the TCB. */   \
  62                                         "mov    ds, ax"                                                                     \
  63                                         "les    bx, dword ptr pxCurrentTCB"                                                 \
  64                                         "mov    ss, es:[ bx + 2 ]"                                                          \
  65                                         "mov    sp, es:[ bx ]"                                                              \
  66                                         "mov    bp, sp"                     /* Prepare the bp register for the restoration of the SP in the compiler generated portion of the ISR */    \
  67                                         "add    bp, 0x0002"
  68
  69
  70
  71     #pragma aux portFIRST_CONTEXT =     "mov    ax, seg pxCurrentTCB"           \
  72                                         "mov    ds, ax"                         \
  73                                         "les    bx, dword ptr pxCurrentTCB"     \
  74                                         "mov    ss, es:[ bx + 2 ]"              \
  75                                         "mov    sp, es:[ bx ]"                  \
  76                                         "add    sp, 0x0002"                     /* Remove the extra bytes that exist in debug builds before restoring the context. */ \
  77                                         "pop    ax"                             \
  78                                         "pop    ax"                             \
  79                                         "pop    es"                             \
  80                                         "pop    ds"                             \
  81                                         "popa"                                  \
  82                                         "iret"
  83 #else
  84
  85     #pragma aux portSWITCH_CONTEXT =    "mov    ax, seg pxCurrentTCB"                                                       \
  86                                         "mov    ds, ax"                                                                     \
  87                                         "les    bx, pxCurrentTCB"           /* Save the stack pointer into the TCB. */      \
  88                                         "mov    es:0x2[ bx ], ss"                                                           \
  89                                         "mov    es:[ bx ], sp"                                                              \
  90                                         "call   vTaskSwitchContext"         /* Perform the switch. */                       \
  91                                         "mov    ax, seg pxCurrentTCB"       /* Restore the stack pointer from the TCB. */   \
  92                                         "mov    ds, ax"                                                                     \
  93                                         "les    bx, dword ptr pxCurrentTCB"                                                 \
  94                                         "mov    ss, es:[ bx + 2 ]"                                                          \
  95                                         "mov    sp, es:[ bx ]"
  96
  97
  98     #pragma aux portFIRST_CONTEXT =     "mov    ax, seg pxCurrentTCB"           \
  99                                         "mov    ds, ax"                         \
 100                                         "les    bx, dword ptr pxCurrentTCB"     \
 101                                         "mov    ss, es:[ bx + 2 ]"              \
 102                                         "mov    sp, es:[ bx ]"                  \
 103                                         "pop    ax"                             \
 104                                         "pop    ax"                             \
 105                                         "pop    es"                             \
 106                                         "pop    ds"                             \
 107                                         "popa"                                  \
 108                                         "iret"
 109 #endif