#include <unistd.h>

_syscall2(int, kill, pid_t, pid, int, sig);

void *signal(int sig, void (*func)(int)) {
  void *__res;
  __asm__ volatile (
      "int $0x80"
      : "=a" (__res)
      : "a" (__SYS_signal), "b" (sig), "c" (func)
      );
  return __res;
}