reactos/ntoskrnl/ke/i386/bios.c

   1 /*
   2  *  ReactOS kernel
   3  *  Copyright (C) 2000  ReactOS Team
   4  *
   5  *  This program is free software; you can redistribute it and/or modify
   6  *  it under the terms of the GNU General Public License as published by
   7  *  the Free Software Foundation; either version 2 of the License, or
   8  *  (at your option) any later version.
   9  *
  10  *  This program is distributed in the hope that it will be useful,
  11  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  *  GNU General Public License for more details.
  14  *
  15  *  You should have received a copy of the GNU General Public License
  16  *  along with this program; if not, write to the Free Software
  17  *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  18  */
  19 /*
  20  * PROJECT:         ReactOS kernel
  21  * FILE:            ntoskrnl/ke/i386/bios.c
  22  * PURPOSE:         Support for calling the BIOS in v86 mode
  23  * PROGRAMMER:      David Welch (welch@cwcom.net)
  24  */
  25
  26 /* INCLUDES *****************************************************************/
  27
  28 #include <ntoskrnl.h>
  29 #define NDEBUG
  30 #include <internal/debug.h>
  31
  32 /* GLOBALS *******************************************************************/
  33
  34 #define TRAMPOLINE_BASE    (0x10000)
  35
  36 extern VOID Ki386RetToV86Mode(PKV86M_REGISTERS InRegs,
  37                               PKV86M_REGISTERS OutRegs);
  38
  39 /* FUNCTIONS *****************************************************************/
  40
  41 NTSTATUS STDCALL
  42 Ke386CallBios(UCHAR Int, PKV86M_REGISTERS Regs)
  43 {
  44   PUCHAR Ip;
  45   KV86M_REGISTERS ORegs;
  46   NTSTATUS Status;
  47
  48   /*
  49    * Set up a trampoline for executing the BIOS interrupt
  50    */
  51   Ip = (PUCHAR)TRAMPOLINE_BASE;
  52   Ip[0] = 0xCD;              /* int XX */
  53   Ip[1] = Int;
  54   Ip[2] = 0x63;              /* arpl ax, ax */
  55   Ip[3] = 0xC0;
  56   Ip[4] = 0x90;              /* nop */
  57   Ip[5] = 0x90;              /* nop */
  58
  59   /*
  60    * Munge the registers
  61    */
  62   Regs->Eip = 0;
  63   Regs->Cs = TRAMPOLINE_BASE / 16;
  64   Regs->Esp = 0xFFFF;
  65   Regs->Ss = TRAMPOLINE_BASE / 16;
  66   Regs->Eflags = (1 << 1) | (1 << 17) | (1 << 9);     /* VM, IF */
  67   Regs->RecoveryAddress = TRAMPOLINE_BASE + 2;
  68   Regs->RecoveryInstruction[0] = 0x63;       /* arpl ax, ax */
  69   Regs->RecoveryInstruction[1] = 0xC0;
  70   Regs->RecoveryInstruction[2] = 0x90;       /* nop */
  71   Regs->RecoveryInstruction[3] = 0x90;       /* nop */
  72   Regs->Flags = KV86M_EMULATE_CLI_STI | KV86M_ALLOW_IO_PORT_ACCESS;
  73   Regs->Vif = 1;
  74   Regs->PStatus = &Status;
  75
  76   /*
  77    * Execute the BIOS interrupt
  78    */
  79   Ki386RetToV86Mode(Regs, &ORegs);
  80
  81   /*
  82    * Copy the return values back to the caller
  83    */
  84   memcpy(Regs, &ORegs, sizeof(KV86M_REGISTERS));
  85
  86   return(Status);
  87 }
  88
  89
  90
  91
  92