return at;
__sigreturn (struct sigcontext *scp){  struct hurd_sigstate *ss;  mach_port_t *reply_port;  if (scp == NULL || (scp->sc_mask & _SIG_CANT_MASK))    {      errno = EINVAL;      return -1;    }  ss = _hurd_self_sigstate ();  __spin_lock (&ss->lock);  /* Restore the set of blocked signals, and the intr_port slot.  */  ss->blocked = scp->sc_mask;  ss->intr_port = scp->sc_intr_port;  /* Check for pending signals that were blocked by the old set.  */  if (ss->pending & ~ss->blocked)    {      /* There are pending signals that just became unblocked.  Wake up the	 signal thread to deliver them.  But first, squirrel away SCP where	 the signal thread will notice it if it runs another handler, and	 arrange to have us called over again in the new reality.  */      ss->context = scp;      /* Clear the intr_port slot, since we are not in fact doing	 an interruptible RPC right now.  If SS->intr_port is not null,	 the SCP context is doing an interruptible RPC, but the signal	 thread will examine us while we are blocked in the sig_post RPC.  */      ss->intr_port = MACH_PORT_NULL;      __spin_unlock (&ss->lock);      __msg_sig_post (_hurd_msgport, 0, __mach_task_self ());      /* If a pending signal was handled, sig_post never returned.  */      __spin_lock (&ss->lock);    }  if (scp->sc_onstack)    {      ss->sigaltstack.ss_flags &= ~SA_ONSTACK; /* XXX threadvars */      /* XXX cannot unlock until off sigstack */      abort ();    }  else    __spin_unlock (&ss->lock);  /* Destroy the MiG reply port used by the signal handler, and restore the     reply port in use by the thread when interrupted.  */  reply_port =    (mach_port_t *) __hurd_threadvar_location (_HURD_THREADVAR_MIG_REPLY);  if (*reply_port)    __mach_port_destroy (__mach_task_self (), *reply_port);  *reply_port = scp->sc_reply_port;  if (scp->sc_coproc_used & SC_COPROC_USE_FPU)    {      /* Restore FPU state.  */#define restore_fpr(n) \  asm volatile ("l.d $f" #n ",%0" : : "m" (scp->sc_fpr[n]))      /* Restore floating-point registers. */      restore_fpr (0);      restore_fpr (2);      restore_fpr (4);      restore_fpr (6);      restore_fpr (8);      restore_fpr (10);      restore_fpr (12);      restore_fpr (14);      restore_fpr (16);      restore_fpr (18);      restore_fpr (20);      restore_fpr (22);      restore_fpr (24);      restore_fpr (26);      restore_fpr (28);      restore_fpr (30);      /* Restore the floating-point control/status register ($f31).  */      asm volatile ("ctc1 %0,$f31" : : "r" (scp->sc_fpcsr));    }  /* Load all the registers from the sigcontext.  */#define restore_gpr(n) \  asm volatile ("lw $" #n ",%0" : : "m" (scpreg->sc_gpr[n - 1]))  {    register const struct sigcontext *const scpreg asm ("$1") = scp;    register int *at asm ("$1");    /* First restore the multiplication result registers.  The compiler       will use some temporary registers, so we do this before restoring       the general registers.  */    asm volatile ("mtlo %0" : : "r" (scpreg->sc_mdlo));    asm volatile ("mthi %0" : : "r" (scpreg->sc_mdhi));    /* In the word after the saved PC, store the saved $1 value.  */    (&scpreg->sc_pc)[1] = scpreg->sc_gpr[0];    asm volatile (".set noreorder; .set noat;");    /* Restore the normal registers.  */    restore_gpr (2);    restore_gpr (3);    restore_gpr (4);    restore_gpr (5);    restore_gpr (6);    restore_gpr (7);    restore_gpr (8);    restore_gpr (9);    restore_gpr (10);    restore_gpr (11);    restore_gpr (12);    restore_gpr (13);    restore_gpr (14);    restore_gpr (15);    restore_gpr (16);    restore_gpr (17);    restore_gpr (18);    restore_gpr (19);    restore_gpr (20);    restore_gpr (21);    restore_gpr (22);    restore_gpr (23);    restore_gpr (24);    restore_gpr (25);    /* Registers 26-27 are kernel-only.  */    restore_gpr (28);    restore_gpr (29);		/* Stack pointer.  */    restore_gpr (30);		/* Frame pointer.  */    restore_gpr (31);		/* Return address.  */    at = &scpreg->sc_pc;    /* This is an emulated instruction that will find at the address in $1       two words: the PC value to restore, and the $1 value to restore.  */    asm volatile (".word op_sigreturn");    asm volatile (".set reorder; .set at;");  }  /* NOTREACHED */  return -1;}