Asembler zliczanie a

#include <stdio.h>
#include <string.h>
void main()
{
    char s[] = "Abaaaaaddaaafg";   //char *s = "Abcdefg";
    short int y;
    asm volatile(
    ".intel_syntax noprefix;"
    "mov ebx,%1;"
    "mov cx, 0;"
    "petla:"
    "mov al, [ebx];"
    "sub al, 0;"
    "jz koniec;"
    "cmp al,97;"
    "jnz skocz;"
    "inc cx;"
    "skocz: "

    "inc ebx;"
    "jmp petla;"
    "koniec:"


    "mov %0, cx;"
    ".att_syntax prefix;"
    : "=r" (y)
    : "r" (s)
    : "ebx", "cx", "al"

    );

    printf("s=%s, y=%hd", s, y);

}