ref: 27c74d8b6747a01ae353e06f64e54f017382be6c
dir: /Game/src/audiolib/dpmi.c/
/* Copyright (C) 1994-1995 Apogee Software, Ltd. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ /********************************************************************** module: DPMI.C author: James R. Dose date: April 8, 1994 Functions for performing DPMI calls. (c) Copyright 1994 James R. Dose. All Rights Reserved. **********************************************************************/ #include <dos.h> #include <string.h> #include "dpmi.h" #define TRUE ( 1 == 1 ) #define FALSE ( !TRUE ) static union REGS Regs; static struct SREGS SegRegs; /*--------------------------------------------------------------------- Function: DPMI_GetRealModeVector Returns the vector of a real mode interrupt. ---------------------------------------------------------------------*/ unsigned long DPMI_GetRealModeVector ( int num ) { unsigned long vector; Regs.x.eax = 0x0200; Regs.h.bl = num; int386( 0x31, &Regs, &Regs ); vector = Regs.w.cx & 0xffff; vector <<= 16; vector |= Regs.w.dx & 0xffff; return( vector ); } /*--------------------------------------------------------------------- Function: DPMI_SetRealModeVector Sets the vector of a real mode interrupt. ---------------------------------------------------------------------*/ void DPMI_SetRealModeVector ( int num, unsigned long vector ) { Regs.x.eax = 0x0201; Regs.h.bl = num; Regs.w.dx = vector & 0xffff; Regs.w.cx = ( vector >> 16 ) & 0xffff; int386( 0x31, &Regs, &Regs ); } /*--------------------------------------------------------------------- Function: DPMI_CallRealModeFunction Performs a call to a real mode function. ---------------------------------------------------------------------*/ int DPMI_CallRealModeFunction ( dpmi_regs *callregs ) { // Setup our registers to call DPMI Regs.w.ax = 0x0301; Regs.h.bl = 0; Regs.h.bh = 0; Regs.w.cx = 0; SegRegs.es = FP_SEG( callregs ); Regs.x.edi = FP_OFF( callregs ); // Call Real-mode procedure with Far Return Frame int386x( 0x31, &Regs, &Regs, &SegRegs ); if ( Regs.x.cflag ) { return( DPMI_Error ); } return( DPMI_Ok ); } /*--------------------------------------------------------------------- Function: DPMI_LockMemory Locks a region of memory to keep the virtual memory manager from paging the region out. ---------------------------------------------------------------------*/ int DPMI_LockMemory ( void *address, unsigned length ) { unsigned linear; // Thanks to DOS/4GW's zero-based flat memory model, converting // a pointer of any type to a linear address is trivial. linear = (unsigned) address; // DPMI Lock Linear Region Regs.w.ax = 0x600; // Linear address in BX:CX Regs.w.bx = (linear >> 16); Regs.w.cx = (linear & 0xFFFF); // Length in SI:DI Regs.w.si = (length >> 16); Regs.w.di = (length & 0xFFFF); int386 (0x31, &Regs, &Regs); // Return 0 if can't lock if ( Regs.w.cflag ) { return( DPMI_Error ); } return ( DPMI_Ok ); } /*--------------------------------------------------------------------- Function: DPMI_LockMemoryRegion Locks a region of memory to keep the virtual memory manager from paging the region out. ---------------------------------------------------------------------*/ int DPMI_LockMemoryRegion ( void *start, void *end ) { int status; status = DPMI_LockMemory( start, ( char * )end - ( char * )start ); return( status ); } /*--------------------------------------------------------------------- Function: DPMI_UnlockMemory Unlocks a region of memory that was previously locked. ---------------------------------------------------------------------*/ int DPMI_UnlockMemory ( void *address, unsigned length ) { unsigned linear; // Thanks to DOS/4GW's zero-based flat memory model, converting // a pointer of any type to a linear address is trivial. linear = (unsigned) address; // DPMI Unlock Linear Region Regs.w.ax = 0x601; // Linear address in BX:CX Regs.w.bx = (linear >> 16); Regs.w.cx = (linear & 0xFFFF); // Length in SI:DI Regs.w.si = (length >> 16); Regs.w.di = (length & 0xFFFF); int386 (0x31, &Regs, &Regs); // Return 0 if can't unlock if ( Regs.w.cflag ) { return( DPMI_Error ); } return ( DPMI_Ok ); } /*--------------------------------------------------------------------- Function: DPMI_UnlockMemoryRegion Unlocks a region of memory that was previously locked. ---------------------------------------------------------------------*/ int DPMI_UnlockMemoryRegion ( void *start, void *end ) { int status; status = DPMI_UnlockMemory( start, ( char * )end - ( char * )start ); return( status ); }