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freebsd/usr.bin/doscmd/emuint.c
2002-04-12 21:18:05 +00:00

113 lines
3.7 KiB
C

/*-
* Copyright (c) 1997 Helmut Wirth <hfwirth@ping.at>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice immediately at the beginning of the file, witout modification,
* this list of conditions, and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <ctype.h>
#include "doscmd.h"
#include "emuint.h"
/* The central entry point for the emulator interrupt. This is used by
* different special programs to call the emulator from VM86 space.
* Look at emuint.h for definitions and a list of the currently defined
* subfunctions.
* To call emuint from VM86 space do:
* push ax Save original ax value (*must be done* !)
* mov ah, funcnum Emuint function number to ah
* mov al, subfunc Subfunction number, optional, depending on func
* int 0xff
* ..
* ..
* Emuint saves the function and subfunction numbers internally, then
* pops ax off the stack and calls the function handler with the original
* value in ax.
*/
void
emuint(regcontext_t *REGS)
{
u_short func, subfunc;
/* Remove function number from stack */
func = R_AH;
subfunc = R_AL;
R_AX = POP(REGS);
/* Call the function handler, subfunction is ignored, if unused */
switch (func)
{
/* The redirector call */
case EMU_REDIR:
intff(REGS);
break;
/* EMS call, used by emsdriv.sys */
case EMU_EMS:
{
switch (subfunc)
{
case EMU_EMS_CTL:
R_AX = (u_short)ems_init();
break;
case EMU_EMS_CALL:
ems_entry(REGS);
break;
default:
debug(D_ALWAYS, "Undefined subfunction for EMS call\n");
break;
}
break;
}
default:
debug(D_ALWAYS, "Emulator interrupt called with undefined function %02x\n", func);
/*
* XXX
* temporary backwards compatibility with instbsdi.exe
* remove after a while.
*/
fprintf(stderr, "***\n*** WARNING - unknown emuint function\n");
fprintf(stderr, "*** Continuing; assuming instbsdi redirector.\n");
fprintf(stderr, "*** Please install the new redirector");
fprintf(stderr, " `redir.com' as soon as possible.\n");
fprintf(stderr, "*** This compatibility hack is not permanent.\n");
fprintf(stderr, "***\n");
PUSH(R_AX, REGS);
R_BX = R_ES;
R_DX = R_DI;
R_DI = R_DS;
intff(REGS);
break;
}
}