求教为什么这个圆的子程序无法运行

yuan proc near
push ax
push bx
push cx
push dx
mov ah,0fh ;读取当前显示器模式
int 10h
mov ah,0
mov al,3
int 10h ;显示模式
mov ax,data
mov ds,ax
mov si,0
mov cx,x-r;行
mov dx,y;竖起点坐标
mov al,02 ;像素值
mov ah,0ch ;调用中断画点
int 10h
mov ax,0
mov dx,0
loop1:inc ax;Ab的长度
inc cx;x坐标增一
push ax;保护ax
mov bx,100;2r
sub bx,ax;2r-ax
mul bx;(2r-ax)*ax
mov bx,ax;由bx保存
mov num,0
loop2: pop ax
inc ax;ax++
push ax
inc num;num++
mul ax;ax*ax
cmp ax,bx;比较大小
jb loop2;小于跳转
pop ax
push num
add dx,y
add dx,num
mov al,02
mov ah,0ch
int 10h
pop num
sub dx,num
sub dx,num
mov al,02
mov ah,0ch
int 10h
cmp cx,350
jb p
jmp next
p:pop ax
jmp loop1
next:
mov dx,y-r;列
mov cx,x;竖起点坐标
mov al,02
mov ah,0ch
int 10h
mov ax,0
loop11:
inc ax;
inc dx;y坐标增一
mov yy ,dx
push ax;保护ax
mov bx,100;2r
sub bx,ax;2r-ax
mul bx;(2r-ax)*ax
mov bx,ax;由bx保存
mov num,0
loop21:pop ax
inc ax;ax++
push ax
inc num;num++
mul ax;ax*ax
cmp ax,bx;比较大小
jb loop21;小于跳转
pop ax
push num
mov cx,0
add cx,x
add cx,num
mov dx,yy
mov al,02
mov ah,0ch
int 10h
pop num
sub cx,num
sub cx,num
mov al,02
mov ah,0ch
int 10h
cmp dx,290
jz q
pop ax
jmp loop11
q: pop dx
pop cx
pop bx
pop ax
ret
yuan endp