keyboard.asm

汇编实验 小球碰壁

drawpoly  proc      near
          setcursor 0,20d,20d
          mov       cx,200d          ;set begin cursor position
          mov       dx,200d
          mov       count,2          ;saved point counter
          mov       bx,count
          mov       pointx[bx],cx
          mov       pointy[bx],dx    ;save the begin point
          mov       ah,0ch
          mov       al,9
          int       10h              ;write the begin point
        loopdraw:
          mov       ah,0bh           ;test keyboard input 
          int       21h
          inc       al
          jnz       loopdraw         ;test stack of key press
          mov       ah,07h
          int       21h              ;accept input
          cmp       al,1bh
          je        exitd            ;Esc to exit
          cmp       al,48h           ;up
          je        up
          cmp       al,50h           ;down
          je        down
          cmp       al,4bh           ;left
          je        left
          cmp       al,4dh
          je        right            ;right
          cmp       al,0dh
          je        savepoint        ;Enter to save point
          jmp       loopdraw
        up:
          dec       dx               ;row sub 1
          jmp       drawit
        down:
          inc       dx               ;row add 1
          jmp       drawit
        left:
          dec       cx               ;column sub 1
          jmp       drawit
        right:
          inc       cx               ;column add 1
          jmp       drawit
        savepoint:
          add       count,2          ;if Enter then save the point
          mov       bx,count
          mov       pointx[bx],cx
          mov       pointy[bx],dx
          jmp       loopdraw
        drawit:
          mov       ah,0ch
          mov       al,9             ;write the now point
          int       10h
          jmp       loopdraw         ;continue to draw
        exitd:
          mov       x1,cx            ;laster point
          mov       y1,dx
          mov       ax,200d          ;begin beginning point
          mov       x2,ax
          mov       y2,200d
          call      drawline         ;draw line  between(x1,y1)(x2,y2)
          ret
drawpoly  endp