subp43.asm

来自「x86汇编程序。 从键盘输入一个字符串,先把它原样显示一遍 然后将其中的小写字」· 汇编 代码 · 共 52 行

.model small
.data
.code 
	  public mutual_convert   
    extern in_str:byte, temp_str:byte
.startup

mutual_convert proc near
    push cx
    push si
    push bx

    ;set the counter
    mov cl, in_str + 1
    mov ch, 0
    
    mov si, 2
    
again3:
    mov bl, in_str[si]
    cmp bl, 'A'  
    jb continue3
    cmp bl, 'Z'
    jb to_lower3
    cmp bl, 'a'
    jb continue3
    cmp bl, 'z'
    jb to_upper3
    jmp continue3 
    
to_lower3:
    add bl, 20h
    jmp continue3
    
to_upper3:
    sub bl, 20h
    
continue3:
    mov temp_str[si - 2], bl
    inc si
    loop again3
    
    pop bx
    pop si
    pop cx
    
    ret 
    
mutual_convert endp  

.exit 0
end