这里有一个字符串转换为整数,一对夫妇的功能,反之亦然:
; Input:
; ESI = pointer to the string to convert
; ECX = number of digits in the string (must be > 0)
; Output:
; EAX = integer value
string_to_int:
xor ebx,ebx ; clear ebx
.next_digit:
movzx eax,byte[esi]
inc esi
sub al,'0' ; convert from ASCII to number
imul ebx,10
add ebx,eax ; ebx = ebx*10 + eax
loop .next_digit ; while (--ecx)
mov eax,ebx
ret
; Input:
; EAX = integer value to convert
; ESI = pointer to buffer to store the string in (must have room for at least 10 bytes)
; Output:
; EAX = pointer to the first character of the generated string
int_to_string:
add esi,9
mov byte [esi],STRING_TERMINATOR
mov ebx,10
.next_digit:
xor edx,edx ; Clear edx prior to dividing edx:eax by ebx
div ebx ; eax /= 10
add dl,'0' ; Convert the remainder to ASCII
dec esi ; store characters in reverse order
mov [esi],dl
test eax,eax
jnz .next_digit ; Repeat until eax==0
mov eax,esi
ret
这是你将怎样使用它们:
STRING_TERMINATOR equ 0
lea esi,[thestring]
mov ecx,4
call string_to_int
; EAX now contains 1234
; Convert it back to a string
lea esi,[buffer]
call int_to_string
; You now have a string pointer in EAX, which
; you can use with the sys_write system call
thestring: db "1234",0
buffer: resb 10
请注意,我不在这些例程中不做太多错误检查(例如检查是否有'0' - '9'
范围之外的字符)。例程也不处理带符号的数字。所以如果你需要这些东西,你必须自己添加它们。
我设法比较用户输入和数字: mov ecx,dword [input] 这是否实际上将ecx中的值更改为一个整数? 以及如何将其更改回字符串? – user2862492