汇编-字符串小写转大写

data segment
  org 1000h
  buffer db 'hello ASM!zjh20170623'
  strlen equ $-buffer
  org 2000h
  outstr db strlen dup(?)
  db '$'
data ends

code segment
  assume cs:code,ds:data
start:
  mov ax,data
  mov ds,ax
  ;---------------
  mov cx,strlen
  mov si,0
LP1:
  mov al,[si+buffer]
  cmp al,61h
  jb next
  cmp al,7ah
  ja next
  sub al,20h
next:
  mov [si+outstr],al
  inc si
  loop LP1
output:
  mov dx,offset outstr
  mov ah,09h
  int 21h
  mov ah,4ch
  int 21h
code ends
  end start