我需要提示用户一个消息,告诉他写一个数字,然后存储此数字并对其进行一些操作
在INT 21h中搜索后,我发现了这一点:
INT 21h / AH=1 - read character from standard input, with echo, result is stored in AL.
if there is no character in the keyboard buffer, the function waits until any key is pressed.
example:
mov ah, 1
int 21h
主要问题是,这仅读取一个字符并将其表示为ASCII
所以如果我需要写数字“ 357”
我将其读为3,5,7
这不是我的目标。
有任何想法吗 ?
最佳答案
When you managed to get the user input,将其指针放在ESI中(ESI =字符串的地址)
.DATA
myNumber BYTE "12345",0 ;for test purpose I declare a string '12345'
Main Proc
xor ebx,ebx ;EBX = 0
mov esi,offset myNumber ;ESI points to '12345'
loopme:
lodsb ;load the first byte pointed by ESI in al
cmp al,'0' ;check if it's an ascii number [0-9]
jb noascii ;not ascii, exit
cmp al,'9' ;check the if it's an ascii number [0-9]
ja noascii ;not ascii, exit
sub al,30h ;ascii '0' = 30h, ascii '1' = 31h ...etc.
cbw ;byte to word
cwd ;word to dword
push eax
mov eax,ebx ;EBX will contain '12345' in hexadecimal
mov ecx,10
mul ecx ;AX=AX*10
mov ebx,eax
pop eax
add ebx,eax
jmp loopme ;continue until ESI points to a non-ascii [0-9] character
noascii:
ret ;EBX = 0x00003039 = 12345
Main EndP