usr.bin/doscmd/emuint.c

   1 /*-
   2  * Copyright (c) 1997 Helmut Wirth <hfwirth@ping.at>
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice immediately at the beginning of the file, witout modification,
  10  *    this list of conditions, and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  * 3. The name of the author may not be used to endorse or promote products
  15  *    derived from this software without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  18  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  19  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  20  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  21  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  22  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27  *
  28  * $FreeBSD: src/usr.bin/doscmd/emuint.c,v 1.3.2.2 2002/04/25 11:04:51 tg Exp $
  29  * $DragonFly: src/usr.bin/doscmd/emuint.c,v 1.2 2003/06/17 04:29:26 dillon Exp $
  30  */
  31
  32 #include <sys/param.h>
  33 #include <ctype.h>
  34 #include "doscmd.h"
  35 #include "emuint.h"
  36
  37 /* The central entry point for the emulator interrupt. This is used by
  38  * different special programs to call the emulator from VM86 space.
  39  * Look at emuint.h for definitions and a list of the currently defined
  40  * subfunctions.
  41  * To call emuint from VM86 space do:
  42  *      push ax            Save original ax value (*must be done* !)
  43  *      mov  ah, funcnum   Emuint function number to ah
  44  *      mov  al, subfunc   Subfunction number, optional, depening on func
  45  *      int  0xff
  46  *      ..
  47  *      ..
  48  * Emuint saves the function and subfunction numbers internally, then
  49  * pops ax off the stack and calls the function handler with the original
  50  * value in ax.
  51  */
  52 void
  53 emuint(regcontext_t *REGS)
  54 {
  55     u_short func, subfunc;
  56
  57     /* Remove function number from stack */
  58     func = R_AH;
  59     subfunc = R_AL;
  60
  61     R_AX = POP(REGS);
  62
  63     /* Call the function handler, subfunction is ignored, if unused */
  64     switch (func)
  65     {
  66         /* The redirector call */
  67         case EMU_REDIR:
  68             intff(REGS);
  69             break;
  70
  71         /* EMS call, used by emsdriv.sys */
  72         case EMU_EMS:
  73         {
  74             switch (subfunc)
  75             {
  76                 case EMU_EMS_CTL:
  77                     R_AX = (u_short)ems_init();
  78                     break;
  79
  80                 case EMU_EMS_CALL:
  81                     ems_entry(REGS);
  82                     break;
  83
  84                 default:
  85                     debug(D_ALWAYS, "Undefined subfunction for EMS call\n");
  86                     break;
  87             }
  88             break;
  89         }
  90
  91         default:
  92             debug(D_ALWAYS, "Emulator interrupt called with undefined function %02x\n", func);
  93
  94             /*
  95              * XXX
  96              * temporary backwards compatibility with instbsdi.exe
  97              * remove after a while.
  98              */
  99             fprintf(stderr, "***\n*** WARNING - unknown emuint function\n");
 100             fprintf(stderr, "*** Continuing; assuming instbsdi redirector.\n");
 101             fprintf(stderr, "*** Please install the new redirector");
 102             fprintf(stderr, " `redir.com' as soon as possible.\n");
 103             fprintf(stderr, "*** This compatibility hack is not permanent.\n");
 104             fprintf(stderr, "***\n");
 105             PUSH(R_AX, REGS);
 106             R_BX = R_ES;
 107             R_DX = R_DI;
 108             R_DI = R_DS;
 109             intff(REGS);
 110             break;
 111     }
 112 }