#include "dos.h"



void interrupt ( *prevtimer )( ) ;

void interrupt mytimer( ) ;



int running = 0 ;

unsigned long far *time = ( unsigned long far * ) 0x46C ;

char far *scr ;

char far *mode ;



main( )

{



/* peek into location 0:410h and determine video mode */

if ( ( *mode & 0x30 ) == 0x30 )

scr = ( char far * ) 0xB0000000 ;

else

scr = ( char far * ) 0xB8000000 ;



prevtimer = getvect ( 8 ) ;

setvect ( 8, mytimer ) ;

keep ( 0, 1000 ) ;



}



void interrupt mytimer( )

{

unsigned char hours, sec, min ;



if ( running == 0 )

{



running = 1;

hours = ( *time / 65520 ) ;

min = ( *time - hours * 65520 ) / 1092 ;

sec = ( *time - hours * 65520 - min * 1092 ) * 10 / 182 ;



if ( sec >= 60 )

{



sec -= 60 ;

min++ ;



if ( min == 60 )

{



min = 0 ;

hours++ ;



if ( hours == 24 )

hours = 0 ;



}



}







/* display digital clock */

writechar ( 48 + hours / 10, 0, 72, 112 ) ;

writechar ( 48 + hours % 10, 0, 73, 112 ) ;

writechar ( ':', 0, 74, 112 ) ;

writechar ( 48 + min / 10, 0, 75, 112 ) ;

writechar ( 48 + min % 10, 0, 76, 112 ) ;

writechar ( ':', 0, 77, 112 ) ;

writechar ( 48 + sec / 10, 0, 78, 112 ) ;

writechar ( 48 + sec % 10, 0, 79, 112 ) ;



running = 0 ;



}



( *prevtimer )( ) ;



}







writechar ( char ch, int row, int col, int attr )

{



*( scr + row * 160 + col * 2 ) = ch ;

*( scr + row * 160 + col * 2 + 1 ) = attr ;



}