实验11

avatar10010

;初学汇编希望给点意见

assume cs:code
code segment

words db "Beginner's All-purpose Symbolic Instruction Code."
start:
    xor si,0
         call letterc
        mov ax,4c00h
    int 21h

letterc:
    push si
begin:
    cmp byte ptr words[si],0
    je return1
    cmp byte ptr words[si],'a'
    jb return2
    cmp byte ptr words[si],'z'
    ja return2
    and byte ptr words[si],11011111b
return2:
        inc si
        loop begin
return1:
    pop si
    ret

code ends
end start