git.sur5r.net Git - freertos/blob - FreeRTOS/Source/portable/BCC/16BitDOS/common/portcomn.c

   1 /*\r
   2     FreeRTOS V8.0.0 - Copyright (C) 2014 Real Time Engineers Ltd. \r
   3     All rights reserved\r
   4 \r
   5     VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.\r
   6 \r
   7     ***************************************************************************\r
   8      *                                                                       *\r
   9      *    FreeRTOS provides completely free yet professionally developed,    *\r
  10      *    robust, strictly quality controlled, supported, and cross          *\r
  11      *    platform software that has become a de facto standard.             *\r
  12      *                                                                       *\r
  13      *    Help yourself get started quickly and support the FreeRTOS         *\r
  14      *    project by purchasing a FreeRTOS tutorial book, reference          *\r
  15      *    manual, or both from: http://www.FreeRTOS.org/Documentation        *\r
  16      *                                                                       *\r
  17      *    Thank you!                                                         *\r
  18      *                                                                       *\r
  19     ***************************************************************************\r
  20 \r
  21     This file is part of the FreeRTOS distribution.\r
  22 \r
  23     FreeRTOS is free software; you can redistribute it and/or modify it under\r
  24     the terms of the GNU General Public License (version 2) as published by the\r
  25     Free Software Foundation >>!AND MODIFIED BY!<< the FreeRTOS exception.\r
  26 \r
  27     >>! NOTE: The modification to the GPL is included to allow you to distribute\r
  28     >>! a combined work that includes FreeRTOS without being obliged to provide\r
  29     >>! the source code for proprietary components outside of the FreeRTOS\r
  30     >>! kernel.\r
  31 \r
  32     FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY\r
  33     WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS\r
  34     FOR A PARTICULAR PURPOSE.  Full license text is available from the following\r
  35     link: http://www.freertos.org/a00114.html\r
  36 \r
  37     1 tab == 4 spaces!\r
  38 \r
  39     ***************************************************************************\r
  40      *                                                                       *\r
  41      *    Having a problem?  Start by reading the FAQ "My application does   *\r
  42      *    not run, what could be wrong?"                                     *\r
  43      *                                                                       *\r
  44      *    http://www.FreeRTOS.org/FAQHelp.html                               *\r
  45      *                                                                       *\r
  46     ***************************************************************************\r
  47 \r
  48     http://www.FreeRTOS.org - Documentation, books, training, latest versions,\r
  49     license and Real Time Engineers Ltd. contact details.\r
  50 \r
  51     http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,\r
  52     including FreeRTOS+Trace - an indispensable productivity tool, a DOS\r
  53     compatible FAT file system, and our tiny thread aware UDP/IP stack.\r
  54 \r
  55     http://www.OpenRTOS.com - Real Time Engineers ltd license FreeRTOS to High\r
  56     Integrity Systems to sell under the OpenRTOS brand.  Low cost OpenRTOS\r
  57     licenses offer ticketed support, indemnification and middleware.\r
  58 \r
  59     http://www.SafeRTOS.com - High Integrity Systems also provide a safety\r
  60     engineered and independently SIL3 certified version for use in safety and\r
  61     mission critical applications that require provable dependability.\r
  62 \r
  63     1 tab == 4 spaces!\r
  64 */\r
  65 \r
  66 /*\r
  67 Changes from V1.00:\r
  68 \r
  69         + pxPortInitialiseStack() now initialises the stack of new tasks to the\r
  70           same format used by the compiler.  This allows the compiler generated\r
  71           interrupt mechanism to be used for context switches.\r
  72 \r
  73 Changes from V2.6.1\r
  74 \r
  75         + Move usPortCheckFreeStackSpace() to tasks.c.\r
  76 */\r
  77 \r
  78 \r
  79 #include <dos.h>\r
  80 #include <stdlib.h>\r
  81 #include "FreeRTOS.h"\r
  82 \r
  83 /*-----------------------------------------------------------*/\r
  84 \r
  85 /* See header file for description. */\r
  86 StackType_t *pxPortInitialiseStack( StackType_t *pxTopOfStack, TaskFunction_t pxCode, void *pvParameters )\r
  87 {\r
  88 StackType_t DS_Reg = 0;\r
  89 \r
  90         /* Place a few bytes of known values on the bottom of the stack.\r
  91         This is just useful for debugging. */\r
  92 \r
  93         *pxTopOfStack = 0x1111;\r
  94         pxTopOfStack--;\r
  95         *pxTopOfStack = 0x2222;\r
  96         pxTopOfStack--;\r
  97         *pxTopOfStack = 0x3333;\r
  98         pxTopOfStack--;\r
  99         *pxTopOfStack = 0x4444;\r
 100         pxTopOfStack--;\r
 101         *pxTopOfStack = 0x5555;\r
 102         pxTopOfStack--;\r
 103 \r
 104 \r
 105         /*lint -e950 -e611 -e923 Lint doesn't like this much - but nothing I can do about it. */\r
 106 \r
 107         /* We are going to start the scheduler using a return from interrupt\r
 108         instruction to load the program counter, so first there would be the\r
 109         function call with parameters preamble. */\r
 110         \r
 111         *pxTopOfStack = FP_SEG( pvParameters );\r
 112         pxTopOfStack--;\r
 113         *pxTopOfStack = FP_OFF( pvParameters );\r
 114         pxTopOfStack--;\r
 115         *pxTopOfStack = FP_SEG( pxCode );\r
 116         pxTopOfStack--;\r
 117         *pxTopOfStack = FP_OFF( pxCode );\r
 118         pxTopOfStack--;\r
 119 \r
 120         /* Next the status register and interrupt return address. */\r
 121         *pxTopOfStack = portINITIAL_SW; \r
 122         pxTopOfStack--;\r
 123         *pxTopOfStack = FP_SEG( pxCode );\r
 124         pxTopOfStack--;\r
 125         *pxTopOfStack = FP_OFF( pxCode );\r
 126         pxTopOfStack--;\r
 127 \r
 128         /* The remaining registers would be pushed on the stack by our context\r
 129         switch function.  These are loaded with values simply to make debugging\r
 130         easier. */\r
 131         *pxTopOfStack = ( StackType_t ) 0xAAAA; /* AX */\r
 132         pxTopOfStack--;\r
 133         *pxTopOfStack = ( StackType_t ) 0xBBBB; /* BX */\r
 134         pxTopOfStack--;\r
 135         *pxTopOfStack = ( StackType_t ) 0xCCCC; /* CX */\r
 136         pxTopOfStack--;\r
 137         *pxTopOfStack = ( StackType_t ) 0xDDDD; /* DX */\r
 138         pxTopOfStack--;\r
 139         *pxTopOfStack = ( StackType_t ) 0xEEEE; /* ES */\r
 140         pxTopOfStack--;\r
 141 \r
 142         /* We need the true data segment. */\r
 143         __asm{  MOV DS_Reg, DS };\r
 144 \r
 145         *pxTopOfStack = DS_Reg;                                         /* DS */\r
 146         pxTopOfStack--;\r
 147         *pxTopOfStack = ( StackType_t ) 0x0123; /* SI */\r
 148         pxTopOfStack--;\r
 149         *pxTopOfStack = ( StackType_t ) 0xDDDD; /* DI */\r
 150         pxTopOfStack--;\r
 151         *pxTopOfStack = ( StackType_t ) 0xBBBB; /* BP */\r
 152 \r
 153         /*lint +e950 +e611 +e923 */\r
 154 \r
 155         return pxTopOfStack;\r
 156 }\r
 157 /*-----------------------------------------------------------*/\r
 158 \r