work4.asm

本人的汇编上机的简单的小程序

data segment
      n dw ?
      spn dw 0                            ;每行之前要输出空格数
      isOutput db 0;                      ;每行之前是否输出过空格,1为输出过,否则为0
      two db 2
      tip db "Input number of the first line:(1~9) $"
      tip1 db "Out of range,input again: $"
data ends
stack1 segment para stack
      dw 20h dup(0)
stack1 ends
code segment
      assume cs:code, ds:data, ss:stack1
start:
      mov ax,data
      mov ds,ax

      mov dx,offset tip
      mov ah,09h
      int 21h
      jmp en
re:   mov dl,0dh              ;换行
      mov ah,02h
      int 21h
      mov dl,0ah
      mov ah,02h
      int 21h
      mov dx,offset tip1
      mov ah,09h
      int 21h
en:   mov ah,01h
      int 21h
      sub al,30h
      cmp al,1                ;输入超出范围(1-9),回跳
      jb re
      cmp al,9
      ja re
      test al,01h             ;测试al的奇偶
      jne next                ;是奇数,则不用加1
      inc al                  ;偶数加1
next: mov ah,0
      mov n,ax
      mov dl,0dh              ;换行
      mov ah,02h
      int 21h
      mov dl,0ah
      mov ah,02h
      int 21h
      
      mov ax,n
      inc ax
      div two
      mov ah,0
      mov cx,ax               ;输出行数为2*(n+1)
lop1: push cx
      mov cx,n
lop2: push cx
      mov cx,spn
      cmp isOutput,1
      je ns
      jcxz ns
lop3: mov dl,20h              ;每行之前输出的空格
      mov ah,02h
      int 21h
      loop lop3
      mov isOutput,1          ;该行已经输出空格

ns:   pop cx
      mov dl,'*'
      mov ah,02h
      int 21h
      mov dl,20h              ;输出空格
      mov ah,02h
      int 21h
      loop lop2
      
      mov dl,0dh              ;换行
      mov ah,02h
      int 21h
      mov dl,0ah
      mov ah,02h
      int 21h
      mov isOutput,0          ;新一行没输出空格
      sub n,2                 ;每行输出"*"的个数计数
      add spn,2               ;每行之前输出空格计数
      pop cx
      loop lop1
      
      
      mov ah,4ch
      int 21h
code  ends
      end start