diff --git a/C/sysbits.c b/C/sysbits.c
index ee1e67a3d..752499a7c 100755
--- a/C/sysbits.c
+++ b/C/sysbits.c
@@ -1033,6 +1033,139 @@ p_srandom (void)
 
 STATIC_PROTO (void InitSignals, (void));
 
+#define PLSIG_PREPARED 0x01		/* signal is prepared */
+#define PLSIG_THROW    0x02		/* throw signal(num, name) */
+#define PLSIG_SYNC     0x04		/* call synchronously */
+#define PLSIG_NOFRAME  0x08		/* Do not create a Prolog frame */
+
+#define SIG_PROLOG_OFFSET	32	/* Start of Prolog signals */
+
+#define SIG_EXCEPTION	  (SIG_PROLOG_OFFSET+0)
+#ifdef O_ATOMGC
+#define SIG_ATOM_GC	  (SIG_PROLOG_OFFSET+1)
+#endif
+#define SIG_GC		  (SIG_PROLOG_OFFSET+2)
+#ifdef O_PLMT
+#define SIG_THREAD_SIGNAL (SIG_PROLOG_OFFSET+3)
+#endif
+#define SIG_FREECLAUSES	  (SIG_PROLOG_OFFSET+4)
+#define SIG_PLABORT	  (SIG_PROLOG_OFFSET+5)
+
+static struct signame
+{ int 	      sig;
+  const char *name;
+  int	      flags;
+} signames[] =
+{
+#ifdef SIGHUP
+  { SIGHUP,	"hup",    0},
+#endif
+  { SIGINT,	"int",    0},
+#ifdef SIGQUIT
+  { SIGQUIT,	"quit",   0},
+#endif
+  { SIGILL,	"ill",    0},
+  { SIGABRT,	"abrt",   0},
+  { SIGFPE,	"fpe",    PLSIG_THROW},
+#ifdef SIGKILL
+  { SIGKILL,	"kill",   0},
+#endif
+  { SIGSEGV,	"segv",   0},
+#ifdef SIGPIPE
+  { SIGPIPE,	"pipe",   0},
+#endif
+#ifdef SIGALRM
+  { SIGALRM,	"alrm",   PLSIG_THROW},
+#endif
+  { SIGTERM,	"term",   0},
+#ifdef SIGUSR1
+  { SIGUSR1,	"usr1",   0},
+#endif
+#ifdef SIGUSR2
+  { SIGUSR2,	"usr2",   0},
+#endif
+#ifdef SIGCHLD
+  { SIGCHLD,	"chld",   0},
+#endif
+#ifdef SIGCONT
+  { SIGCONT,	"cont",   0},
+#endif
+#ifdef SIGSTOP
+  { SIGSTOP,	"stop",   0},
+#endif
+#ifdef SIGTSTP
+  { SIGTSTP,	"tstp",   0},
+#endif
+#ifdef SIGTTIN
+  { SIGTTIN,	"ttin",   0},
+#endif
+#ifdef SIGTTOU
+  { SIGTTOU,	"ttou",   0},
+#endif
+#ifdef SIGTRAP
+  { SIGTRAP,	"trap",   0},
+#endif
+#ifdef SIGBUS
+  { SIGBUS,	"bus",    0},
+#endif
+#ifdef SIGSTKFLT
+  { SIGSTKFLT,	"stkflt", 0},
+#endif
+#ifdef SIGURG
+  { SIGURG,	"urg",    0},
+#endif
+#ifdef SIGIO
+  { SIGIO,	"io",     0},
+#endif
+#ifdef SIGPOLL
+  { SIGPOLL,	"poll",   0},
+#endif
+#ifdef SIGXCPU
+  { SIGXCPU,	"xcpu",   PLSIG_THROW},
+#endif
+#ifdef SIGXFSZ
+  { SIGXFSZ,	"xfsz",   PLSIG_THROW},
+#endif
+#ifdef SIGVTALRM
+  { SIGVTALRM,	"vtalrm", PLSIG_THROW},
+#endif
+#ifdef SIGPROF
+  { SIGPROF,	"prof",   0},
+#endif
+#ifdef SIGPWR
+  { SIGPWR,	"pwr",    0},
+#endif
+  { SIG_EXCEPTION,     "prolog:exception",     0 },
+#ifdef SIG_ATOM_GC
+  { SIG_ATOM_GC,   "prolog:atom_gc",       0 },
+#endif
+  { SIG_GC,	       "prolog:gc",	       0 },
+#ifdef SIG_THREAD_SIGNAL
+  { SIG_THREAD_SIGNAL, "prolog:thread_signal", 0 },
+#endif
+
+  { -1,		NULL,     0}
+};
+
+/* SWI emulation */
+int
+Yap_signal_index(const char *name)
+{ struct signame *sn = signames;
+  char tmp[12];
+
+  if ( strncmp(name, "SIG", 3) == 0 && strlen(name) < 12 ) 
+    { char *p = (char *)name+3, *q = tmp;
+      while ((*q++ = tolower(*p++))) {};
+      name = tmp;
+    }
+
+  for( ; sn->name; sn++ )
+  { if ( !strcmp(sn->name, name) )
+      return sn->sig;
+  }
+
+  return -1;
+}
 
 #if (defined(__svr4__) || defined(__SVR4))
 
diff --git a/H/Yapproto.h b/H/Yapproto.h
index ed46bce5f..2f72ec84e 100755
--- a/H/Yapproto.h
+++ b/H/Yapproto.h
@@ -328,6 +328,7 @@ Int	STD_PROTO(Yap_walltime,(void));
 int	STD_PROTO(Yap_dir_separator,(int));
 int	STD_PROTO(Yap_volume_header,(char *));
 void	STD_PROTO(Yap_InitSysPath,(void));
+int	STD_PROTO(Yap_signal_index,(const char *));
 #ifdef MAC
 void	STD_PROTO(Yap_SetTextFile,(char *));
 #endif
diff --git a/packages/PLStream/pl-yap.c b/packages/PLStream/pl-yap.c
index ae96e86e3..34732b29e 100644
--- a/packages/PLStream/pl-yap.c
+++ b/packages/PLStream/pl-yap.c
@@ -203,12 +203,36 @@ _PL_unify_atomic(term_t t, PL_atomic_t a)
 
 word lookupAtom(const char *s, size_t len)
 {
-  return (word)YAP_LookupAtom(s);
+  if (len >= strlen(s)) {
+    return (word)YAP_LookupAtom(s);
+  } else {
+    char * buf = PL_malloc(len+1);
+    word out;
+
+    if (!buf)
+      return 0;
+    strncpy(buf,s,len);
+    out = (word)YAP_LookupAtom(buf);
+    PL_free(buf);
+    return out;
+  }
 }
 
 atom_t lookupUCSAtom(const pl_wchar_t *s, size_t len)
 {
-  return (atom_t)YAP_LookupWideAtom(s);
+  if (len >= wcslen(s)) {
+    return (atom_t)YAP_LookupWideAtom(s);
+  } else {
+    pl_wchar_t * buf = PL_malloc((len+1)*sizeof(pl_wchar_t));
+    word out;
+
+    if (!buf)
+      return 0;
+    wcsncpy(buf,s,len);
+    out = (word)YAP_LookupWideAtom(buf);
+    PL_free(buf);
+    return out;
+  }
 }