522.asm

汇编语言的简单的输入字母的大小写转换的小汇编语言程序

data segment
     buffer db 27 dup(?)
     h db 13,10,'$'
     result db ?,?,?,13,10,'$'
data ends
code segment
     assume cs:code,ds:data
start:
      mov ax,data
      mov ds,ax 
      lea bx,buffer
      mov cl,0   
next:
      mov ah,1
      int 21h
      inc cl
      cmp al,0dh
      jz number
      mov [bx],al
      inc bx
      jmp next                             
number:
      mov ch,0      ;cx循环次数
      mov dh,cl
      mov dl,0      ;dl为计数器
      lea bx,buffer
loop1: 
      mov al,[bx]
      cmp al,30h
      jb t0         ;(AL)<‘0’结束
      cmp al,39h
      ja t0         ;(AL)>’9’转移 
      inc dl        ;(AL)在‘0’~‘9’之间      
t0:
      inc bx
      loop loop1
      add dl,30h   
      mov result+1,dl
letter:
      mov cl,dh     ;cx循环次数 
      mov dh,cl
      mov ch,0
      mov dl,0      ;dl为计数器
      lea bx,buffer
loop2:                                    
      mov al,[bx]
      cmp al,41h
      jb exit       ;(AL)<‘A’结束
      cmp al,5ah
      ja t2         ;(AL)>’Z’转移  
      inc dl
      jmp exit
t2:
      cmp al,61h
      jb exit        ;(AL)<‘a’结束 
      cmp al,7ah
      ja exit        ;(AL)>’z’结束
      inc dl      
exit:
      inc bx
      loop loop2 
      add dl,30h  
      mov result,dl

      mov al,result    ;计算非字母和数字的个数        
      mov bl,result+1
      add dh,90h       ;因为AL，BL已经加过30H
      sub dh,al
      sub dh,bl
      mov result+2,dh

      mov ah,9       ;输出
      mov dx,seg h
      mov ds,dx
      mov dx,offset h
      int 21h

      mov ah,9       ;输出
      mov dx,seg result
      mov ds,dx
      mov dx,offset result
      int 21h
      mov ah,4ch
      int 21h
code ends
end start