Category : Linux Files
Archive   : UPC12BS1.ZIP
Filename : SCRSIZE.C

/*--------------------------------------------------------------------*/
/* s c r s i z e . c */
/* */
/* Report screen size under MS-DOS */
/* */
/* Copyright (c) 1992 by Kendra Electronic Wonderworks. */
/* All rights reserved except those explicitly granted by */
/* the UUPC/extended license. */
/*--------------------------------------------------------------------*/

/*
* $Id: SCRSIZE.C 1.6 1993/05/03 02:41:57 ahd Exp $
*
* $Log: SCRSIZE.C $
* Revision 1.6 1993/05/03 02:41:57 ahd
* Trap funky screen size on pre-DOS 4.0 boxes (poor babies...)
*
* Revision 1.5 1992/12/30 05:27:11 plummer
* MS C compile fixes
*
* Revision 1.4 1992/12/18 12:05:57 ahd
* Fix query for ANSI sys
*
* Revision 1.3 1992/12/11 12:45:11 ahd
* Use BIOS values if no ANSI driver
*
* Revision 1.2 1992/11/29 22:09:10 ahd
* Add stdlib.h for _osmajor under MSC
*
* Revision 1.1 1992/11/27 14:36:10 ahd
* Initial revision
*
*/

/*--------------------------------------------------------------------*/
/* System include files */
/*--------------------------------------------------------------------*/

#include
#include
#include

/*--------------------------------------------------------------------*/
/* UUPC/extended include files */
/*--------------------------------------------------------------------*/

#include "lib.h"
#include "scrsize.h"

/*--------------------------------------------------------------------*/
/* s c r s i z e */
/* */
/* Return screen size under MS-DOS 4.0 and 5.0 */
/*--------------------------------------------------------------------*/

short scrsize( void )
{

#ifdef __TURBOC__
static unsigned char far *bios_rows = MK_FP( 0x0040, 0x0084 );
/* static unsigned char far *bios_cols = MK_FP( 0x40, 0x4a ); */
#else
static unsigned char far *bios_rows = 0x0484;
#endif

static boolean error = FALSE;
static short default_rows = 0;

typedef struct _DISPLAYMODE /* Page 310 MS-DOS 5.0 PGMR Reference */
{
char dmInfoLevel;
char dmReserved1;
short dmDataLength;
short dmFlags;
char dmMode;
char dmReserved2;
short dmColors;
short dmWidth;
short dmLength;
short dmColumns;
short dmRows;

} DISPLAYMODE;

DISPLAYMODE info;

union REGS regs;

/*--------------------------------------------------------------------*/
/* If an old version of DOS, return stock size */
/*--------------------------------------------------------------------*/

if ((*bios_rows < 20 ) || (*bios_rows > 99)) /* Sanity check */
default_rows = 24;

if ((_osmajor < 4) || error )
return (short) (default_rows ? default_rows : *bios_rows);
/* Faster, but not well documented */

/*--------------------------------------------------------------------*/
/* Fill in information to perform processing */
/*--------------------------------------------------------------------*/

info.dmInfoLevel = 0; /* Magic number in book */
info.dmReserved1 = 0; /* Magic number in book */
info.dmReserved2 = 0; /* Magic number in book */
info.dmDataLength = 14; /* Magic number in book */

regs.x.bx = 0x0001; /* STDOUT file handle */
regs.h.ch = 0x03; /* Screen device category */
regs.h.cl = 0x7f; /* Get display mode */
regs.x.ax = 0x440c; /* Video Status */
regs.x.dx = (short) &info; /* Address of structure */

intdos(®s, ®s );

/*--------------------------------------------------------------------*/
/* If we have an error, set up to use the BIOS information (or */
/* a fixed default) on future calls. Otherwise, return the */
/* ANSI supplied value. */
/*--------------------------------------------------------------------*/

if ( regs.x.cflag )
{
printmsg(2,"DOS error %d retrieving screen size, using BIOS value %d",
(int) regs.x.ax,
(short) (default_rows ? default_rows : *bios_rows ));
error = TRUE;
return (short) (default_rows ? default_rows : *bios_rows);
/* Faster, but not well documented */
}
else
return info.dmRows;

} /* scrsize */