汇编程序输入一个16进制数，输出对应的十进制数
code segment
assume cs:code
main proc far
push ds
xor ax,ax
push ax
call input
call change
ret
main endp
input proc near
mov bx,0
P1:
mov ah,1
int 21h
cmp al,30H
jl exit
cmp al,39H
jle P2
cmp al,41H
jl exit
cmp al,5aH
jg exit
P2:
sub al,30H
cmp al,9
jle P3
sub al,7
P3:
rol bx,1
rol bx,1
rol bx,1
rol bx,1
add bl,al
jmp P1
exit:
ret
input endp
change proc near
mov ax,bx
mov bx,10
mov cx,0
P4:
mov dx,0
div bx
inc cx
push dx
or ax,ax
jnz P4
P5:
pop dx
add dl,30H
mov ah,2
int 21h
loop P5
ret
change endp
code ends
end main
采用的是对16进制数除以16，每次的余数和10进制转2进制一样，从低到高。