square.gif

assume cs:code

code segment
start:

    mov dh,10
    mov dl,30
    mov cl,2
    mov ch,3
    mov al,0
    call clear
    call sleep
s:
    call rhombus
    call sleep
    call clear
    add al,2
    cmp al,6
    je s1
    jmp s 

s1:
    call rhombus
    call sleep
    call clear
    sub al,2
    cmp al,-2
    je finish
    jmp s1

finish:
    mov ax,4c00h
    int 21h

clear:
    push bx
    push cx
    push es
    mov bx,0b800h
    mov es,bx
    mov cx,2000
    mov bx,0
    s2:
        mov byte ptr es:[bx],' '
        add bx,2
    loop s2
    pop es
    pop cx
    pop bx
    ret

;dh 行 dl 列 ch 字符 cl 颜色 ah 距原点距离 中心的菱形
rhombus:
    push ax
    push cx
    push dx

    sub dh,al
    call show
    sub dl,al
    call show
    add dh,al
    call show
    add dh,al
    call show
    add dl,al
    call show
    add dl,al
    call show
    sub dh,al
    call show
    sub dh,al
    call show
    pop dx
    pop cx
    pop ax
    ret


;dh 行 dl 列 ch 字符 cl 颜色
show:
    push dx
    push bx
    push ax
    mov ax,0b800h
    mov es,ax
    mov ax,160
    mul dh
    mov bx,ax
    mov ax,2
    mul dl
    add bx,ax
    mov es:[bx],cl
    mov es:[bx+1],ch
    pop ax
    pop bx
    pop dx
    ret
sleep:
    push ax
    mov al,0
    out 70h,al
    in al,71h
    mov ah,al
slp0:
    mov al,0
    out 70h,al
    in al,71h
    ;sub al,ah
    cmp al,ah
    jne over
    jmp slp0
over:
    pop ax
    ret
code ends
end start

sleep函数说明：

*获取系统时钟，当秒数改变时跳出
*jne over 若将其换为je，上面换为
sub al,ah
cmp al,1
当系统时间为59s时会发生错误
且当系统时间为9s，10s也会发生错误，因为系统时间是以bcd码存放