read.txt

汇编语言 多模块的实现

public read       
Code segment
         assume cs: Code
        read    proc far
        push bx
        push cx
        push dx
        xor bx,bx
        xor cx,cx
        mov ah,1
        int 21h
        cmp al,'+'
        jz read1
        cmp al,'-'
        jnz read2
        mov cx,-1
read1:  mov ah,1
             int 21h
read2:  cmp al,'0'    
        jb read3
        cmp al,'9'
        ja read3
        sub al,30h         

 shl bx,1
        mov dx,bx
        shl bx,1
        shl bx,1
        add bx,dx
        
        mov ah,0
        add bx,ax
        jmp read1
read3:  cmp cx,0
        jz read4
        neg bx
read4:  mov ax,bx
        pop dx
        pop cx
        pop bx
        ret
read    endp
       
Code  ends
          end