汇编-将数据区的字符串逆序输出

data segment
str db 'Hello World!','$'
data ends

code segment
assume cs:code,ds:data
main proc far
mov ax,data
mov ds,ax

lea si,str
mov cx,0
LP1:
cmp byte ptr [si],'$'
je  output
inc si
inc cx
jmp LP1

output:
lea si,str
add si,cx
dec si
mov dl,[si]
mov ah,02h
int 21h
dec si
loop output

mov ax,4c00h
int 21h

code ends
end main