Draw a Circle(Midpoint Algorithm)

        print macro msg         lea dx,msg         mov ah,09h         int 21h     endm     read macro n,j1,j2         mov cx,0ah     j1:mov ah,01h         int 21h         cmp al,0dh         je j2         sub al,30h         mov bl,al         mov ax,n         mul cx         xor bh,bh         add ax,bx         mov n,ax         jmp j1     j2 :nop     endm     .model small     .stack 100h     .data         f db 0         n db 0         msg1 db 10,13,'Enter the center $'         msg2 db 10,13,'X cordinate: $'         msg3 db 10,13,'y cordinate: $'         msg4 db 10,13,'Enter the radius: $'         xc dw 0         yc dw 0         x dw 0         y dw 0         p dw 0         r dw 0     .code     main proc         mov ax,@data         mov ds,ax         ;read center(x,y)         print msg1         print msg2         read xc,ju1,ju2         print msg3         read yc,ju3,ju4         print msg4         read r,ju,ju6         ;selecting screen         mov ah,00         int 10h         ;select mode 12         mov al,12h         int 10h         ;plot the center         mov ah,0ch         mov al,05         mov cx,xc         mov dx,yc         int 10h         ;draw circle(midpoint algorithm)         ;y=r         mov ax,r         mov y,ax         ;plot initial point         call plot         ;p=1-r         mov ax,01         mov dx,r         xor dx,0ffffh         inc dx         add ax,dx         mov p,ax         ;while(x<y)     loop1: mov ax,x         cmp ax,y         jnc jump1         ;x++         inc x         ;if(p<0)         mov ax,p         rcl ax,01         jnc jump2         ;p+=2*x+1         mov ax,x         rcl ax,01         inc ax         add ax,p         jmp jump3         ;else         ;y++         ;p+=2*(x-y)+1;     jump2: dec y         mov ax,x         mov dx,y         xor dx,0ffffh         inc dx         add ax,dx         rcl ax,01         jnc jump4         or ax,8000h     jump4: inc ax         add ax,p     jump3: mov p,ax         ;plot point         call plot         jmp loop1     jump1: mov ah,00         int 16h         mov ax,0003         int 10h         stop:mov ah,4ch         int 21h     main endp     plot proc     mov ah,0ch         mov al,02         mov cx,xc         add cx,x         mov dx,yc         add dx,y         int 10h         mov cx,xc         add cx,x         mov dx,yc         sub dx,y         int 10h         mov cx,xc         sub cx,x         mov dx,yc         add dx,y         int 10h         mov cx,xc         sub cx,x         mov dx,yc         sub dx,y         int 10h         mov cx,xc         add cx,y         mov dx,yc         add dx,x         int 10h         mov cx,xc         add cx,y         mov dx,yc         sub dx,x         int 10h         mov cx,xc         sub cx,y         mov dx,yc         add dx,x         int 10h         mov cx,xc         sub cx,y         mov dx,yc         sub dx,x         int 10h         ret     plot endp     end