push    0 0 0 0
        push    FUTEX_WAIT
        push    __TimerExpiredFutex

        mov     eax, sys_futex
        mov     ebx, esp
        int $80
        add     esp, 6*4
    

int sys_futex(void *futex, int op, int val, const struct timespec *timeout, void *futex2, int val3);    

mov eax, sys_futex 
mov ebx, futex
mov ecx, [op]
mov edx, [val]
mov esi, timeout
mov edi, futex2
mov ebp, [val3]
int $80
    

4.3 System call parameters

On i386, the parameters of a system call are transported via registers. The system call number goes into %eax, the first parameter in %ebx, the second in %ecx, the third in %edx, the fourth in %esi, the fifth in %edi, the sixth in %ebp.
Ancient history

Earlier versions of Linux could handle only four or five system call parameters, and therefore the system calls select() (5 parameters) and mmap() (6 parameters) used to have a single parameter that was a pointer to a parameter block in memory. Since Linux 1.3.0 five parameters are supported (and the earlier select with memory block was renamed old_select), and since Linux 2.3.31 six parameters are supported (and the earlier mmap with memory block was succeeded by the new mmap2).