int fork()
{
  int pid;
  __asm__ __volatile__ (
	"movl $2, %%eax\n"
	"int $0x80\n"
	"movl %%eax,%0\n"
	"cmpl $0,%%eax\n"
	"jge else4\n"
	"neg %%eax\n"
	"movl %%eax,%1\n"
	"movl $-1,%0\n"
	"jmp endif4\n"
	"else4:\n"
	"movl %%eax,%0\n"
	"endif4:"
	:"=g" (pid), "=g" (errno)
  );
  return pid;
}

void exit()
{
  __asm__ (
	"movl $1, %%eax\n"
	"int $0x80\n"
	"cmpl $0,%%eax\n"
	"jge else3\n"
	"neg %%eax\n"
	"movl %%eax,%0\n"
	"else3:"
	:"=g" (errno)
  );
}

int get_stats(int pid, int *tics){
  int sortida;
  __asm__ __volatile__ (
	"pushl %%ebx\n"
	"movl %2,%%ebx\n"
	"movl %3,%%ecx\n"
	"movl $35, %%eax\n"
	"int $0x80\n"
	"movl %%eax,%0\n"
	"cmpl $0,%%eax\n"
	"jge else6\n"
	"neg %%eax\n"
	"movl %%eax,%1\n"
	"movl $-1,%0\n"
	"jmp endif6\n"
	"else6:\n"
	"movl $0,%0\n"
	"endif6:\n"
	"popl %%ebx"
	:"=g" (sortida), "=g" (errno)
	:"g" (pid), "g" (tics)
  );
  return sortida;
}

int sem_init (int n_sem, unsigned int value)
{
  int sortida;

  if (n_sem < 0) {
     errno = 22; //EINVAL
     sortida = -1;
  }else{
     __asm__ __volatile__ (
	"pushl %%ebx\n"
	"movl %2, %%ebx\n"
	"movl %3, %%ecx\n"
	"movl $21, %%eax\n"
	"int $0x80\n"
	"movl %%eax,%0\n"
	"cmpl $0,%%eax\n"
	"jge else7\n"
	"neg %%eax\n"
	"movl %%eax,%1\n"
	"movl $-1,%0\n"
	"jmp endif7\n"
	"else7:\n"
	"movl $0,%0\n"
	"endif7:\n"
	"popl %%ebx"
	:"=g" (sortida), "=g" (errno)
	:"g" (n_sem), "g" (value)
      );
  }
  return sortida;
}

int sem_wait (int n_sem)
{
  int sortida;

  if (n_sem < 0) {
     errno = 22; //EINVAL
     sortida = -1;
  }else{
     __asm__ __volatile__ (
	"pushl %%ebx\n"
	"movl %2, %%ebx\n"
	"movl $22, %%eax\n"
	"int $0x80\n"
	"movl %%eax,%0\n"
	"cmpl $0,%%eax\n"
	"jge else8\n"
	"neg %%eax\n"
	"movl %%eax,%1\n"
	"movl $-1,%0\n"
	"jmp endif8\n"
	"else8:\n"
	"movl $0,%0\n"
	"endif8:\n"
	"popl %%ebx"
	:"=g" (sortida), "=g" (errno)
	:"g" (n_sem)
      );
  }
  return sortida;
}

int sem_signal (int n_sem)
{
  int sortida;

  if (n_sem < 0) {
     errno = 22; //EINVAL
     sortida = -1;
  }else{
     __asm__ __volatile__ (
	"pushl %%ebx\n"
	"movl %2, %%ebx\n"
	"movl $23, %%eax\n"
	"int $0x80\n"
	"movl %%eax,%0\n"
	"cmpl $0,%%eax\n"
	"jge else9\n"
	"neg %%eax\n"
	"movl %%eax,%1\n"
	"movl $-1,%0\n"
	"jmp endif9\n"
	"else9:\n"
	"movl $0,%0\n"
	"endif9:\n"
	"popl %%ebx"
	:"=g" (sortida), "=g" (errno)
	:"g" (n_sem)
      );
  }
  return sortida;
}

int sem_destroy (int n_sem)
{
  int sortida;

  if (n_sem < 0) {
     errno = 22; //EINVAL
     sortida = -1;
  }else{
     __asm__ __volatile__ (
	"pushl %%ebx\n"
	"movl %2, %%ebx\n"
	"movl $24, %%eax\n"
	"int $0x80\n"
	"movl %%eax,%0\n"
	"cmpl $0,%%eax\n"
	"jge else10\n"
	"neg %%eax\n"
	"movl %%eax,%1\n"
	"movl $-1,%0\n"
	"jmp endif10\n"
	"else10:\n"
	"movl $0,%0\n"
	"endif10:\n"
	"popl %%ebx"
	:"=g" (sortida), "=g" (errno)
	:"g" (n_sem)
      );
  }
  return sortida;
}