4.asm

华工电信系汇编习题的编程实现

stack segment stack 'stack'
      dw 32 dup (?)
stack ends

data segment
     DecIN db 7,0,8 dup(?)
     HexOut db 4 dup(?),'$'
data ends

code segment
    begin proc far
    assume ss:stack,cs:code,ds:data
    push ds
    sub ax,ax
    push ax
    mov ax,data
    mov ds,ax

    mov dx,offset DecIn
    mov ah,10
    int 21H

    mov cl,DecIn[1]
    mov ch,0

    mov SI,offset DecIn + 2
    mov al,[SI]
    CMP al,'-'
    pushf
    mov ax,0
    mov bx,0
    JNZ PLUS
    INC SI
    DEC cx
PLUS:


AGAIN:
    mov bl,[SI]
    sub bl,030H
    CMP bl,00AH
    JS SHUZI
    sub bl,7
SHUZI:
    mov dh,0
    mov dl,10
    Mul dx
    add ax,bx
    INC SI
  LOOP AGAIN
    mov SI,offset HexOut + 3
    popf
    mov cx,4
    JNZ ZHENG
    NEG ax
ZHENG:
    mov bx,ax
    and bl,00FH
    CMP bl,0AH
    JS NUM
    add bl,7 
NUM:
    add bl,030H
    mov [SI],bl
    DEC SI
    push cx
    mov cl,4
    shr ax,cl
    pop cx
  LOOP ZHENG
    INC SI

    mov dl,00AH
    mov ah,2
    int 21H

    mov dx,SI
    mov ah,9
    INT 21H

    ret
begin endp
code ends
     end begin