C Program Using 8086 Interrupts to Restrict Mouse Pointer Into a Circle of Given Center and Radius

C Program Using 8086 Interrupts to Restrict Mouse Pointer Into a Circle of Given Center and Radius. The mouse ponter will be restricted to a circle of user specified center and radius using the interrupt 33 of 8086 in c complier. I have tested this program in Turbo C compiler.

Mouse pointer restricted into a circle in Turbo C

#include<stdio.h>
#include<conio.h>
#include<dos.h>
#include<graphics.h>

void main()
 {
 int x,y,tx,ty,r;
 union REGS inreg, outreg;
 /* request auto detection */
 int gdriver = DETECT, gmode, errorcode;
 clrscr();
 /* initialize graphics and local variables */
 initgraph(&gdriver, &gmode,"C:\\TC\\BGI\\" );
 /* read result of initialization */
 errorcode = graphresult();
 if (errorcode != grOk)  /* an error occurred */
  {
  printf("Graphics error: %s\n", grapherrormsg(errorcode));
  printf("Press any key to halt:");
  getch();
  exit(1); /* terminate with an error code */
  }
 setcolor(getmaxcolor());
 printf("\nEnter the center of circle. x and y");
 scanf("%d%d",&x,&y);
 printf("\nEnter the radius of circle");
 scanf("%d",&r);
 clrscr();
 circle(x,y,r);
 inreg.x.ax=0x1;
 int86(0x33,&inreg,&outreg);
 inreg.x.ax=0x7;
 inreg.x.cx=x-r;
 inreg.x.dx=x+r;
 int86(0x33,&inreg,&outreg);
 inreg.x.ax=0x8;
 inreg.x.cx=y-r;
 inreg.x.dx=y+r;
 int86(0x33,&inreg,&outreg);
 do
 {
  inreg.x.ax=0x3;
  int86(0x33,&inreg,&outreg);
  tx=outreg.x.cx;
  ty=outreg.x.dx;
  if((tx-x)*(tx-x)+(ty-y)*(ty-y)>r*r)
   {
   if(tx<=x)
   {
   if(ty<y)
    do{tx++; ty++;}while((tx-x)*(tx-x)+(ty-y)*(ty-y)>=r*r);
   else
    do{tx++; ty--;}while((tx-x)*(tx-x)+(ty-y)*(ty-y)>=r*r);
   }
   else
   {
   if(ty<=y)
    do{tx--; ty++;}while((tx-x)*(tx-x)+(ty-y)*(ty-y)>=r*r);
   else
    do{tx--; ty--;}while((tx-x)*(tx-x)+(ty-y)*(ty-y)>=r*r);
   }
   inreg.x.ax=0x4;
   inreg.x.cx=tx;
   inreg.x.dx=ty;
   int86(0x33,&inreg,&outreg);
   }
 }while(1);
}

C Program to Display and Set System Time and Date Using 8086 Interrupts

This is a C Program to Display and Set System Time and Date Using 8086 Interrupts. Interrupt number 21 (in hexadecimal) is used to:

Output of c Program to get and set system time and date 

• Get System time
• Set System time
• Get System Date
• Set System Date

To Get system date:

- Call interrupt 0x21 (hexadecimal) 

- AH (higher byte of accumulator) should be made equal to 2A (hex) before calling interrupt

Output:

• day in DL
• Month in DH
• Year in CX

To set System Date:

- Call interrupt 0x21 (hexadecimal) 

- AH (higher byte of accumulator) should be made equal to 2B (hex) before calling interrupt

- Before Calling interrupt, store:

• Year in CX
• Month in DH
• Day in DL

To Get system time:

- Call interrupt 0x21 (hexadecimal) 

- AH (higher byte of accumulator) should be made equal to 2C (hex) before calling interrupt

Output:

• Hours in CH
• Minutes in CL
• Seconds in DH
• 1/100 th of a second in DL

To set System Time:







- Call interrupt 0x21 (hexadecimal) 

- AH (higher byte of accumulator) should be made equal to 2D (hex) before calling interrupt
- Before Calling interrupt, store:

Hour in CH 
Minutes in CL
Seconds in DH 
1/100 th of second in DL

#include<stdio.h>
#include<dos.h>
#include<conio.h>

void main()
 {
 int day,month,year,tflag=0,dflag=0,hr,min,sec;
 union REGS inreg,outreg;
DISDATE:printf("\nCurrent date:\n");
 inreg.h.ah=0x2a;
 int86(0x21,&inreg,&outreg);
 printf("%d-%d-%d ",outreg.h.dl,outreg.h.dh,outreg.x.cx);
 switch(outreg.h.al)
  {
  case 0:printf("Sunday");break;
  case 1:printf("Monday");break;
  case 2:printf("Tueday");break;
  case 3:printf("Wednesday");break;
  case 4:printf("Thursday");break;
  case 5:printf("Friday");break;
  case 6:printf("Sunday");break;
  }
 if(dflag==1)
  goto SETTIME;
DISTIME:printf("\nCurrent Time:\n");
 inreg.h.ah=0x2c;
 int86(0x21,&inreg,&outreg);
 printf("%d:%d:%d.%d ",outreg.h.ch,outreg.h.cl,outreg.h.dh,outreg.h.dl);
 if(tflag==1)
  goto END;
SETDATE:printf("\nSet Date.\nDay,Month and Year\n");
 scanf("%d%d%d",&day,&month,&year);
 inreg.h.ah=0x2b;
 inreg.x.cx=year;
 inreg.h.dh=month;
 inreg.h.dl=day;
 int86(0x21,&inreg,&outreg);
 if(outreg.h.al==0x00)
  {
  dflag=1;
  goto DISDATE;
  }
 else
  {
  printf("\nInvalid entry");
  getch();
  exit(0);
  }
SETTIME:printf("\nSet Time. Enter Time.\nHour,Minutes and Seconds\n");
 scanf("%d%d%d",&hr,&min,&sec);
 inreg.h.ah=0x2d;
 inreg.h.ch=hr;
 inreg.h.dh=sec;
 inreg.h.cl=min;
 inreg.h.dl=0;
 int86(0x21,&inreg,&outreg);
 if(outreg.h.al==0x00)
  {
  tflag=1;
  goto DISTIME;
  }
 else
  {
  printf("\nInvalid entry");
  getch();
  exit(0);
  }
END: getch();
 }

C Program to Display SCAN and ASCII Codes of Keys on Keyboard Using 8086 Interrupt

Output (ASCII and SCAN code) when a is pressed

This program displays SCAN code and ASCII code of any key pressed on the keyboard. We use inregs is made zero in the program. Then interrupt 16h is called using int86() function in dos.h. The arguments are interrupt number (in hexadecimal ; in C 0x16) pointer to input register and pointer to output register.
The interrupt stores scan code in higher byte of accumulator and ASCII code in lower byte of accumulator.

8086 interrupt number 16h (hexadecimal) to read a keystroke from keyboard. The condition for this interrupt is that the higher byte of accumulator (AH) should be 00h.

#include<stdio.h>
#include<dos.h>
#include<conio.h>
void main()
 {
 union REGS inregs,outregs; //declaring 2 register files
 clrscr();
 inregs.h.ah=0x0; //pre-requisite for desired operation of interrupt 16h
 int86(0x16,&inregs,&outregs); //calling interrupt 16h
 printf("\nScan Code :%d\nASCII code:%d\n",outregs.h.ah,outregs.h.al);
 getch();
 }