Interrupts management

syscalls_interrupt

GETFROMSTACK(ustack, unsigned int, n, 0);
GETFROMSTACK(ustack, void *, f, 1);
GETFROMSTACK(ustack, void *, data, 2);
GETFROMSTACK(ustack, unsigned int, cond, 3);
GETFROMSTACK(ustack, unsigned int *, handle, 4);

Installs interrupt handler f for interrupt given by n.