#include "dos.h"

void interrupt myfunc();

void interrupt (*prev)();

int ticks;

unsigned char color;

char far *vdu=(char far*)0xb8000000l;

main()

{

//AIM : TSR to change the color of the screen every 3 seconds

unsigned long far *p;

p=(unsigned long far *)32;

prev=(void (interrupt far*)())*p;

*p=(unsigned long)myfunc;

keep(0,500);

return 0;

}

void interrupt myfunc()

{

int i;

ticks++;

if (ticks==182/4)

{

for(i=1;i<3999;i+=2,*(vdu+i)=color);

ticks=0;

color++;

}//if

(*prev)();

}