From 739a1839ed354dce699a6942c31896f61084b231 Mon Sep 17 00:00:00 2001
From: steve <steve>
Date: Tue, 24 May 2005 01:44:27 +0000
Subject: [PATCH]  Do sign extension of structuran nets.

---
 design_dump.cc      | 13 ++++++++++++-
 elab_net.cc         | 18 ++++++++++++++----
 elaborate.cc        | 17 +++++++++++++----
 emit.cc             | 10 +++++++++-
 functor.cc          | 14 +++++++++++++-
 functor.h           |  7 ++++++-
 ivl_target.h        | 11 ++++++++++-
 netlist.cc          | 23 ++++++++++++++++++++++-
 netlist.h           | 28 +++++++++++++++++++++++++++-
 netmisc.h           |  7 ++++++-
 pad_to_width.cc     | 28 +++++++++++++++++++++++++++-
 t-dll-api.cc        | 10 +++++++++-
 t-dll.cc            | 33 ++++++++++++++++++++++++++++++++-
 t-dll.h             |  8 ++++++--
 target.cc           | 12 +++++++++++-
 target.h            |  6 +++++-
 tgt-stub/stub.c     | 29 ++++++++++++++++++++++++++++-
 tgt-vvp/vvp_scope.c | 18 +++++++++++++++++-
 18 files changed, 267 insertions(+), 25 deletions(-)

diff --git a/design_dump.cc b/design_dump.cc
index 0669991bc..a28a87042 100644
--- a/design_dump.cc
+++ b/design_dump.cc
@@ -17,7 +17,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #ifdef HAVE_CVS_IDENT
-#ident "$Id: design_dump.cc,v 1.159 2005/05/17 20:56:55 steve Exp $"
+#ident "$Id: design_dump.cc,v 1.160 2005/05/24 01:44:27 steve Exp $"
 #endif
 
 # include "config.h"
@@ -388,6 +388,14 @@ void NetReplicate::dump_node(ostream&o, unsigned ind) const
       dump_obj_attr(o, ind+4);
 }
 
+void NetSignExtend::dump_node(ostream&o, unsigned ind) const
+{
+      o << setw(ind) << "" << "NetSignExtend: "
+	<< name() << " output width=" << width_ << endl;
+      dump_node_pins(o, ind+4);
+      dump_obj_attr(o, ind+4);
+}
+
 void NetUReduce::dump_node(ostream&o, unsigned ind) const
 {
       o << setw(ind) << "" << "reduction logic: ";
@@ -1143,6 +1151,9 @@ void Design::dump(ostream&o) const
 
 /*
  * $Log: design_dump.cc,v $
+ * Revision 1.160  2005/05/24 01:44:27  steve
+ *  Do sign extension of structuran nets.
+ *
  * Revision 1.159  2005/05/17 20:56:55  steve
  *  Parameters cannot have their width changed.
  *
diff --git a/elab_net.cc b/elab_net.cc
index 21d327808..befe21ddf 100644
--- a/elab_net.cc
+++ b/elab_net.cc
@@ -17,7 +17,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #ifdef HAVE_CVS_IDENT
-#ident "$Id: elab_net.cc,v 1.164 2005/05/19 03:51:38 steve Exp $"
+#ident "$Id: elab_net.cc,v 1.165 2005/05/24 01:44:27 steve Exp $"
 #endif
 
 # include "config.h"
@@ -901,20 +901,27 @@ NetNet* PEBinary::elaborate_net_mul_(Design*des, NetScope*scope,
       NetNet*rsig = right_->elaborate_net(des, scope, lwidth, 0, 0, 0);
       if (rsig == 0) return 0;
 
+	// The mult is signed if both its operands are signed.
+      bool arith_is_signed = lsig->get_signed() && rsig->get_signed();
+
       unsigned rwidth = lwidth;
       if (rwidth == 0) {
-	    rwidth = lsig->pin_count() + rsig->pin_count();
+	    rwidth = lsig->vector_width() + rsig->vector_width();
 	    lwidth = rwidth;
       }
 
+      if (arith_is_signed) {
+	    lsig = pad_to_width_signed(des, lsig, rwidth);
+	    rsig = pad_to_width_signed(des, rsig, rwidth);
+      }
+
       NetMult*mult = new NetMult(scope, scope->local_symbol(), rwidth,
 				 lsig->vector_width(),
 				 rsig->vector_width());
       mult->set_line(*this);
       des->add_node(mult);
 
-	// The mult is signed if both its operands are signed.
-      mult->set_signed( lsig->get_signed() && rsig->get_signed() );
+      mult->set_signed( arith_is_signed );
 
       connect(mult->pin_DataA(), lsig->pin(0));
       connect(mult->pin_DataB(), rsig->pin(0));
@@ -2461,6 +2468,9 @@ NetNet* PEUnary::elaborate_net(Design*des, NetScope*scope,
 
 /*
  * $Log: elab_net.cc,v $
+ * Revision 1.165  2005/05/24 01:44:27  steve
+ *  Do sign extension of structuran nets.
+ *
  * Revision 1.164  2005/05/19 03:51:38  steve
  *  Make sure comparison widths match.
  *
diff --git a/elaborate.cc b/elaborate.cc
index bb9758687..59a895821 100644
--- a/elaborate.cc
+++ b/elaborate.cc
@@ -17,7 +17,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #ifdef HAVE_CVS_IDENT
-#ident "$Id: elaborate.cc,v 1.323 2005/05/17 20:56:55 steve Exp $"
+#ident "$Id: elaborate.cc,v 1.324 2005/05/24 01:44:27 steve Exp $"
 #endif
 
 # include "config.h"
@@ -157,9 +157,15 @@ void PGAssign::elaborate(Design*des, NetScope*scope) const
 		 it to the desired width. */
 	    if (cnt < lval->vector_width()) {
 		  if (lval->get_signed() && rid->get_signed()) {
-			cerr << get_line() << ": internal error: "
-			     << "Forgot how to sign-extend r-value "
-			     << "to l-value." << endl;
+
+			unsigned use_width = lval->vector_width();
+
+			if (debug_elaborate)
+			      cerr << get_line() << ": debug: PGassign "
+				   << "Generate sign-extend node." << endl;
+
+			rid = pad_to_width_signed(des, rid, use_width);
+
 		  } else {
 
 			if (debug_elaborate)
@@ -2965,6 +2971,9 @@ Design* elaborate(list<perm_string>roots)
 
 /*
  * $Log: elaborate.cc,v $
+ * Revision 1.324  2005/05/24 01:44:27  steve
+ *  Do sign extension of structuran nets.
+ *
  * Revision 1.323  2005/05/17 20:56:55  steve
  *  Parameters cannot have their width changed.
  *
diff --git a/emit.cc b/emit.cc
index cf83012a3..d2197af6f 100644
--- a/emit.cc
+++ b/emit.cc
@@ -17,7 +17,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #ifdef HAVE_CVS_IDENT
-#ident "$Id: emit.cc,v 1.83 2005/02/08 00:12:36 steve Exp $"
+#ident "$Id: emit.cc,v 1.84 2005/05/24 01:44:27 steve Exp $"
 #endif
 
 # include "config.h"
@@ -131,6 +131,11 @@ bool NetReplicate::emit_node(struct target_t*tgt) const
       return tgt->replicate(this);
 }
 
+bool NetSignExtend::emit_node(struct target_t*tgt) const
+{
+      return tgt->sign_extend(this);
+}
+
 bool NetUReduce::emit_node(struct target_t*tgt) const
 {
       return tgt->ureduce(this);
@@ -523,6 +528,9 @@ int emit(const Design*des, const char*type)
 
 /*
  * $Log: emit.cc,v $
+ * Revision 1.84  2005/05/24 01:44:27  steve
+ *  Do sign extension of structuran nets.
+ *
  * Revision 1.83  2005/02/08 00:12:36  steve
  *  Add the NetRepeat node, and code generator support.
  *
diff --git a/functor.cc b/functor.cc
index a37d6f270..542292262 100644
--- a/functor.cc
+++ b/functor.cc
@@ -17,7 +17,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #ifdef HAVE_CVS_IDENT
-#ident "$Id: functor.cc,v 1.33 2005/02/03 04:56:20 steve Exp $"
+#ident "$Id: functor.cc,v 1.34 2005/05/24 01:44:27 steve Exp $"
 #endif
 
 # include "config.h"
@@ -79,6 +79,10 @@ void functor_t::lpm_mux(class Design*, class NetMux*)
 {
 }
 
+void functor_t::sign_extend(class Design*, class NetSignExtend*)
+{
+}
+
 void functor_t::lpm_ureduce(class Design*, class NetUReduce*)
 {
 }
@@ -210,6 +214,11 @@ void NetMux::functor_node(Design*des, functor_t*fun)
       fun->lpm_mux(des, this);
 }
 
+void NetSignExtend::functor_node(Design*des, functor_t*fun)
+{
+      fun->sign_extend(des, this);
+}
+
 void NetUReduce::functor_node(Design*des, functor_t*fun)
 {
       fun->lpm_ureduce(des, this);
@@ -276,6 +285,9 @@ int proc_match_t::event_wait(NetEvWait*)
 
 /*
  * $Log: functor.cc,v $
+ * Revision 1.34  2005/05/24 01:44:27  steve
+ *  Do sign extension of structuran nets.
+ *
  * Revision 1.33  2005/02/03 04:56:20  steve
  *  laborate reduction gates into LPM_RED_ nodes.
  *
diff --git a/functor.h b/functor.h
index fcf66e1c7..2b7f4873f 100644
--- a/functor.h
+++ b/functor.h
@@ -19,7 +19,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #ifdef HAVE_CVS_IDENT
-#ident "$Id: functor.h,v 1.21 2005/02/03 04:56:20 steve Exp $"
+#ident "$Id: functor.h,v 1.22 2005/05/24 01:44:27 steve Exp $"
 #endif
 
 /*
@@ -80,6 +80,8 @@ struct functor_t {
 
 	/* This method is called for each unary reduction gate. */
       virtual void lpm_ureduce(class Design*des, class NetUReduce*);
+
+      virtual void sign_extend(class Design*des, class NetSignExtend*);
 };
 
 struct proc_match_t {
@@ -95,6 +97,9 @@ struct proc_match_t {
 
 /*
  * $Log: functor.h,v $
+ * Revision 1.22  2005/05/24 01:44:27  steve
+ *  Do sign extension of structuran nets.
+ *
  * Revision 1.21  2005/02/03 04:56:20  steve
  *  laborate reduction gates into LPM_RED_ nodes.
  *
diff --git a/ivl_target.h b/ivl_target.h
index df548d1ef..867ae035b 100644
--- a/ivl_target.h
+++ b/ivl_target.h
@@ -19,7 +19,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #ifdef HAVE_CVS_IDENT
-#ident "$Id: ivl_target.h,v 1.154 2005/05/08 23:44:08 steve Exp $"
+#ident "$Id: ivl_target.h,v 1.155 2005/05/24 01:44:28 steve Exp $"
 #endif
 
 #ifdef __cplusplus
@@ -247,6 +247,7 @@ typedef enum ivl_lpm_type_e {
       IVL_LPM_REPEAT = 26,
       IVL_LPM_SHIFTL =  6,
       IVL_LPM_SHIFTR =  7,
+      IVL_LPM_SIGN_EXT=27,
       IVL_LPM_SUB    =  8,
       IVL_LPM_RAM    =  9,
       IVL_LPM_UFUNC  = 14
@@ -933,6 +934,11 @@ extern const char* ivl_udp_name(ivl_udp_t net);
  * repeated to get the desired width. The ivl core assures that the
  * input vector is exactly ivl_lpm_width() / ivl_lpm_size() bits.
  *
+ * - Sign Exend (IVL_LPM_SIGN_EXT)
+ * This node takes a single input and generates a single output. The
+ * input must be signed, and the output will be a vector sign extended
+ * to the desired width. The ivl_lpm_width() value is the output
+ * width, the input will be whatever it wants to be.
  * - Shifts (IVL_LPM_SHIFTL/SHIFTR)
  * This node takes two inputs, a vector and a shift distance. The
  * ivl_lpm_data(0) nexus is the vector input, and the ivl_lpm_data(1)
@@ -1658,6 +1664,9 @@ _END_DECL
 
 /*
  * $Log: ivl_target.h,v $
+ * Revision 1.155  2005/05/24 01:44:28  steve
+ *  Do sign extension of structuran nets.
+ *
  * Revision 1.154  2005/05/08 23:44:08  steve
  *  Add support for variable part select.
  *
diff --git a/netlist.cc b/netlist.cc
index 95e8db924..cf0c1ff9f 100644
--- a/netlist.cc
+++ b/netlist.cc
@@ -17,7 +17,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #ifdef HAVE_CVS_IDENT
-#ident "$Id: netlist.cc,v 1.243 2005/05/08 23:44:08 steve Exp $"
+#ident "$Id: netlist.cc,v 1.244 2005/05/24 01:44:28 steve Exp $"
 #endif
 
 # include "config.h"
@@ -1474,6 +1474,24 @@ const Link& NetRamDq::pin_Q() const
       return pin(5);
 }
 
+NetSignExtend::NetSignExtend(NetScope*s, perm_string n, unsigned w)
+: NetNode(s, n, 2), width_(w)
+{
+      pin(0).set_dir(Link::OUTPUT);
+      pin(1).set_dir(Link::INPUT);
+      pin(0).set_name(perm_string::literal("O"), 0);
+      pin(1).set_name(perm_string::literal("I"), 0);
+}
+
+NetSignExtend::~NetSignExtend()
+{
+}
+
+unsigned NetSignExtend::width() const
+{
+      return width_;
+}
+
 NetBUFZ::NetBUFZ(NetScope*s, perm_string n, unsigned w)
 : NetNode(s, n, 2), width_(w)
 {
@@ -2185,6 +2203,9 @@ const NetProc*NetTaskDef::proc() const
 
 /*
  * $Log: netlist.cc,v $
+ * Revision 1.244  2005/05/24 01:44:28  steve
+ *  Do sign extension of structuran nets.
+ *
  * Revision 1.243  2005/05/08 23:44:08  steve
  *  Add support for variable part select.
  *
diff --git a/netlist.h b/netlist.h
index c0a07ff10..d0042a3a1 100644
--- a/netlist.h
+++ b/netlist.h
@@ -19,7 +19,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #ifdef HAVE_CVS_IDENT
-#ident "$Id: netlist.h,v 1.343 2005/05/17 20:56:55 steve Exp $"
+#ident "$Id: netlist.h,v 1.344 2005/05/24 01:44:28 steve Exp $"
 #endif
 
 /*
@@ -1364,6 +1364,29 @@ class NetLogic  : public NetNode {
       unsigned width_;
 };
 
+/*
+ * This class represents a structural sign extension. The pin-0 is a
+ * vector of the input pin-1 sign-extended. The input is taken to be
+ * signed. This generally matches a hardware implementation of
+ * replicating the top bit enough times to create the desired output
+ * width.
+ */
+class NetSignExtend  : public NetNode {
+
+    public:
+      explicit NetSignExtend(NetScope*s, perm_string n, unsigned wid);
+      ~NetSignExtend();
+
+      unsigned width() const;
+
+      virtual void dump_node(ostream&, unsigned ind) const;
+      virtual bool emit_node(struct target_t*) const;
+      virtual void functor_node(Design*, functor_t*);
+
+    private:
+      unsigned width_;
+};
+
 /*
  * This class represents *reduction* logic operators. Certain boolean
  * logic operators have reduction forms which take in a vector and
@@ -3444,6 +3467,9 @@ extern ostream& operator << (ostream&, NetNet::Type);
 
 /*
  * $Log: netlist.h,v $
+ * Revision 1.344  2005/05/24 01:44:28  steve
+ *  Do sign extension of structuran nets.
+ *
  * Revision 1.343  2005/05/17 20:56:55  steve
  *  Parameters cannot have their width changed.
  *
diff --git a/netmisc.h b/netmisc.h
index 6c96ddc62..706d85855 100644
--- a/netmisc.h
+++ b/netmisc.h
@@ -19,7 +19,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #ifdef HAVE_CVS_IDENT
-#ident "$Id: netmisc.h,v 1.21 2005/04/24 23:44:02 steve Exp $"
+#ident "$Id: netmisc.h,v 1.22 2005/05/24 01:44:28 steve Exp $"
 #endif
 
 # include  "netlist.h"
@@ -50,6 +50,8 @@ extern NetScope* symbol_search(Design*des, NetScope*start, hname_t path,
 extern NetExpr*pad_to_width(NetExpr*expr, unsigned wid);
 extern NetNet*pad_to_width(Design*des, NetNet*n, unsigned w);
 
+extern NetNet*pad_to_width_signed(Design*des, NetNet*n, unsigned w);
+
 /*
  * This function transforms an expression by cropping the high bits
  * off with a part select. The result has the width w passed in. This
@@ -99,6 +101,9 @@ extern NetExpr* elab_and_eval(Design*des, NetScope*scope, const PExpr*pe);
 
 /*
  * $Log: netmisc.h,v $
+ * Revision 1.22  2005/05/24 01:44:28  steve
+ *  Do sign extension of structuran nets.
+ *
  * Revision 1.21  2005/04/24 23:44:02  steve
  *  Update DFF support to new data flow.
  *
diff --git a/pad_to_width.cc b/pad_to_width.cc
index 2bc2cbf9e..ba54bc371 100644
--- a/pad_to_width.cc
+++ b/pad_to_width.cc
@@ -17,7 +17,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #ifdef HAVE_CVS_IDENT
-#ident "$Id: pad_to_width.cc,v 1.17 2005/04/24 23:44:02 steve Exp $"
+#ident "$Id: pad_to_width.cc,v 1.18 2005/05/24 01:44:28 steve Exp $"
 #endif
 
 # include "config.h"
@@ -110,6 +110,29 @@ NetNet*pad_to_width(Design*des, NetNet*net, unsigned wid)
       return tmp;
 }
 
+NetNet*pad_to_width_signed(Design*des, NetNet*net, unsigned wid)
+{
+      NetScope*scope = net->scope();
+
+      if (net->vector_width() >= wid)
+	    return net;
+
+      NetSignExtend*se
+	    = new NetSignExtend(scope, scope->local_symbol(), wid);
+      se->set_line(*net);
+      des->add_node(se);
+
+      NetNet*tmp = new NetNet(scope, scope->local_symbol(), NetNet::WIRE, wid);
+      tmp->set_line(*net);
+      tmp->local_flag(true);
+      tmp->set_signed(true);
+
+      connect(tmp->pin(0), se->pin(0));
+      connect(se->pin(1), net->pin(0));
+
+      return tmp;
+}
+
 NetNet*crop_to_width(Design*des, NetNet*net, unsigned wid)
 {
       NetScope*scope = net->scope();
@@ -132,6 +155,9 @@ NetNet*crop_to_width(Design*des, NetNet*net, unsigned wid)
 
 /*
  * $Log: pad_to_width.cc,v $
+ * Revision 1.18  2005/05/24 01:44:28  steve
+ *  Do sign extension of structuran nets.
+ *
  * Revision 1.17  2005/04/24 23:44:02  steve
  *  Update DFF support to new data flow.
  *
diff --git a/t-dll-api.cc b/t-dll-api.cc
index 5b8059bf8..e0bad4f63 100644
--- a/t-dll-api.cc
+++ b/t-dll-api.cc
@@ -17,7 +17,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #ifdef HAVE_CVS_IDENT
-#ident "$Id: t-dll-api.cc,v 1.126 2005/05/08 23:44:08 steve Exp $"
+#ident "$Id: t-dll-api.cc,v 1.127 2005/05/24 01:44:28 steve Exp $"
 #endif
 
 # include "config.h"
@@ -803,6 +803,7 @@ extern "C" ivl_nexus_t ivl_lpm_data(ivl_lpm_t net, unsigned idx)
 	  case IVL_LPM_RE_NAND:
 	  case IVL_LPM_RE_NOR:
 	  case IVL_LPM_RE_XNOR:
+	  case IVL_LPM_SIGN_EXT:
 	    assert(idx == 0);
 	    return net->u_.reduce.a;
 
@@ -982,6 +983,7 @@ extern "C" ivl_nexus_t ivl_lpm_q(ivl_lpm_t net, unsigned idx)
 	  case IVL_LPM_RE_NAND:
 	  case IVL_LPM_RE_NOR:
 	  case IVL_LPM_RE_XNOR:
+	  case IVL_LPM_SIGN_EXT:
 	    assert(idx == 0);
 	    return net->u_.reduce.q;
 
@@ -1078,6 +1080,8 @@ extern "C" int ivl_lpm_signed(ivl_lpm_t net)
 	  case IVL_LPM_SHIFTL:
 	  case IVL_LPM_SHIFTR:
 	    return net->u_.shift.signed_flag;
+	  case IVL_LPM_SIGN_EXT: // Sign extend is always signed.
+	    return 1;
 	  case IVL_LPM_UFUNC:
 	    return 0;
 	  case IVL_LPM_CONCAT: // Concatenations are always unsigned
@@ -1140,6 +1144,7 @@ extern "C" unsigned ivl_lpm_width(ivl_lpm_t net)
 	  case IVL_LPM_RE_NAND:
 	  case IVL_LPM_RE_NOR:
 	  case IVL_LPM_RE_XNOR:
+	  case IVL_LPM_SIGN_EXT:
 	    return net->u_.reduce.width;
 	  case IVL_LPM_SHIFTL:
 	  case IVL_LPM_SHIFTR:
@@ -2035,6 +2040,9 @@ extern "C" ivl_variable_type_t ivl_variable_type(ivl_variable_t net)
 
 /*
  * $Log: t-dll-api.cc,v $
+ * Revision 1.127  2005/05/24 01:44:28  steve
+ *  Do sign extension of structuran nets.
+ *
  * Revision 1.126  2005/05/08 23:44:08  steve
  *  Add support for variable part select.
  *
diff --git a/t-dll.cc b/t-dll.cc
index 44aa304e0..43686ac4b 100644
--- a/t-dll.cc
+++ b/t-dll.cc
@@ -17,7 +17,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #ifdef HAVE_CVS_IDENT
-#ident "$Id: t-dll.cc,v 1.149 2005/05/08 23:44:08 steve Exp $"
+#ident "$Id: t-dll.cc,v 1.150 2005/05/24 01:44:28 steve Exp $"
 #endif
 
 # include "config.h"
@@ -904,6 +904,34 @@ void dll_target::logic(const NetLogic*net)
       scope_add_logic(scope, obj);
 }
 
+bool dll_target::sign_extend(const NetSignExtend*net)
+{
+      struct ivl_lpm_s*obj = new struct ivl_lpm_s;
+      obj->type = IVL_LPM_SIGN_EXT;
+      obj->u_.reduce.width = net->width();
+      obj->name = net->name();
+      obj->scope = find_scope(des_, net->scope());
+      assert(obj->scope);
+
+      const Nexus*nex;
+
+      nex = net->pin(0).nexus();
+      assert(nex->t_cookie());
+
+      obj->u_.reduce.q = (ivl_nexus_t) nex->t_cookie();
+      nexus_lpm_add(obj->u_.reduce.q, obj, 0, IVL_DR_STRONG, IVL_DR_STRONG);
+
+      nex = net->pin(1).nexus();
+      assert(nex->t_cookie());
+
+      obj->u_.reduce.a = (ivl_nexus_t) nex->t_cookie();
+      nexus_lpm_add(obj->u_.reduce.a, obj, 1, IVL_DR_HiZ, IVL_DR_HiZ);
+
+      scope_add_lpm(obj->scope, obj);
+
+      return true;
+}
+
 bool dll_target::ureduce(const NetUReduce*net)
 {
       struct ivl_lpm_s*obj = new struct ivl_lpm_s;
@@ -2080,6 +2108,9 @@ extern const struct target tgt_dll = { "dll", &dll_target_obj };
 
 /*
  * $Log: t-dll.cc,v $
+ * Revision 1.150  2005/05/24 01:44:28  steve
+ *  Do sign extension of structuran nets.
+ *
  * Revision 1.149  2005/05/08 23:44:08  steve
  *  Add support for variable part select.
  *
diff --git a/t-dll.h b/t-dll.h
index 5d528de4d..848ebf199 100644
--- a/t-dll.h
+++ b/t-dll.h
@@ -19,7 +19,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #ifdef HAVE_CVS_IDENT
-#ident "$Id: t-dll.h,v 1.125 2005/05/08 23:44:08 steve Exp $"
+#ident "$Id: t-dll.h,v 1.126 2005/05/24 01:44:28 steve Exp $"
 #endif
 
 # include  "target.h"
@@ -90,6 +90,7 @@ struct dll_target  : public target_t, public expr_scan_t {
       bool net_function(const NetUserFunc*);
       bool net_const(const NetConst*);
       void net_probe(const NetEvProbe*);
+      bool sign_extend(const NetSignExtend*);
 
       bool process(const NetProcTop*);
       void scope(const NetScope*);
@@ -347,7 +348,7 @@ struct ivl_lpm_s {
 		  ivl_nexus_t q, a, s;
 	    } part;
 
-	      // IVL_LPM_RE_* and IVL_LPM_REPEAT use this.
+	      // IVL_LPM_RE_* and IVL_LPM_SIGN_EXT use this.
 	    struct ivl_lpm_reduce_s {
 		  unsigned width;
 		  ivl_nexus_t q,  a;
@@ -685,6 +686,9 @@ struct ivl_variable_s {
 
 /*
  * $Log: t-dll.h,v $
+ * Revision 1.126  2005/05/24 01:44:28  steve
+ *  Do sign extension of structuran nets.
+ *
  * Revision 1.125  2005/05/08 23:44:08  steve
  *  Add support for variable part select.
  *
diff --git a/target.cc b/target.cc
index 6557a30dc..130d7a58b 100644
--- a/target.cc
+++ b/target.cc
@@ -17,7 +17,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #ifdef HAVE_CVS_IDENT
-#ident "$Id: target.cc,v 1.74 2005/02/08 00:12:36 steve Exp $"
+#ident "$Id: target.cc,v 1.75 2005/05/24 01:44:28 steve Exp $"
 #endif
 
 # include "config.h"
@@ -194,6 +194,13 @@ void target_t::net_probe(const NetEvProbe*net)
       net->dump_node(cerr, 4);
 }
 
+bool target_t::sign_extend(const NetSignExtend*net)
+{
+      cerr << "target (" << typeid(*this).name() <<  "): "
+	    "Unhandled NetSignExtend node." << endl;
+      return false;
+}
+
 bool target_t::process(const NetProcTop*top)
 {
       return top->statement()->emit_proc(this);
@@ -429,6 +436,9 @@ void expr_scan_t::expr_binary(const NetEBinary*ex)
 
 /*
  * $Log: target.cc,v $
+ * Revision 1.75  2005/05/24 01:44:28  steve
+ *  Do sign extension of structuran nets.
+ *
  * Revision 1.74  2005/02/08 00:12:36  steve
  *  Add the NetRepeat node, and code generator support.
  *
diff --git a/target.h b/target.h
index 867487e36..a31ab96aa 100644
--- a/target.h
+++ b/target.h
@@ -19,7 +19,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #ifdef HAVE_CVS_IDENT
-#ident "$Id: target.h,v 1.71 2005/02/08 00:12:36 steve Exp $"
+#ident "$Id: target.h,v 1.72 2005/05/24 01:44:28 steve Exp $"
 #endif
 
 # include  "netlist.h"
@@ -99,6 +99,7 @@ struct target_t {
       virtual bool net_const(const NetConst*);
       virtual bool net_function(const NetUserFunc*);
       virtual void net_probe(const NetEvProbe*);
+      virtual bool sign_extend(const NetSignExtend*);
 
 	/* Output a process (called for each process). It is up to the
 	   target to recurse if desired. */
@@ -172,6 +173,9 @@ extern const struct target *target_table[];
 
 /*
  * $Log: target.h,v $
+ * Revision 1.72  2005/05/24 01:44:28  steve
+ *  Do sign extension of structuran nets.
+ *
  * Revision 1.71  2005/02/08 00:12:36  steve
  *  Add the NetRepeat node, and code generator support.
  *
diff --git a/tgt-stub/stub.c b/tgt-stub/stub.c
index 779060cfc..41bcfb035 100644
--- a/tgt-stub/stub.c
+++ b/tgt-stub/stub.c
@@ -17,7 +17,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #ifdef HAVE_CVS_IDENT
-#ident "$Id: stub.c,v 1.125 2005/05/18 03:46:01 steve Exp $"
+#ident "$Id: stub.c,v 1.126 2005/05/24 01:44:28 steve Exp $"
 #endif
 
 # include "config.h"
@@ -739,6 +739,26 @@ static void show_lpm_shift(ivl_lpm_t net, const char*shift_dir)
 	      ivl_nexus_name(nex), width_of_nexus(nex));
 }
 
+static void show_lpm_sign_ext(ivl_lpm_t net)
+{
+      unsigned width = ivl_lpm_width(net);
+      ivl_nexus_t nex_q = ivl_lpm_q(net,0);
+      ivl_nexus_t nex_a = ivl_lpm_data(net,0);
+
+      fprintf(out, "  LPM_SIGN_EXT %s: <width=%u>\n",
+	      ivl_lpm_basename(net), width);
+
+      fprintf(out, "    Q: %s\n", ivl_nexus_name(nex_q));
+      fprintf(out, "    D: %s <width=%u>\n",
+	      ivl_nexus_name(nex_a), width_of_nexus(nex_a));
+
+      if (width != width_of_nexus(nex_q)) {
+	    fprintf(out, "    ERROR: Width of Q is %u, expecting %u\n",
+		    width_of_nexus(nex_q), width);
+	    stub_errors += 1;
+      }
+}
+
 static void show_lpm_sub(ivl_lpm_t net)
 {
       unsigned width = ivl_lpm_width(net);
@@ -830,6 +850,10 @@ static void show_lpm(ivl_lpm_t net)
 	    show_lpm_shift(net, "L");
 	    break;
 
+	  case IVL_LPM_SIGN_EXT:
+	    show_lpm_sign_ext(net);
+	    break;
+
 	  case IVL_LPM_SHIFTR:
 	    show_lpm_shift(net, "R");
 	    break;
@@ -1383,6 +1407,9 @@ int target_design(ivl_design_t des)
 
 /*
  * $Log: stub.c,v $
+ * Revision 1.126  2005/05/24 01:44:28  steve
+ *  Do sign extension of structuran nets.
+ *
  * Revision 1.125  2005/05/18 03:46:01  steve
  *  Fixup structural GT comparators.
  *
diff --git a/tgt-vvp/vvp_scope.c b/tgt-vvp/vvp_scope.c
index 077d6c4ab..121c67369 100644
--- a/tgt-vvp/vvp_scope.c
+++ b/tgt-vvp/vvp_scope.c
@@ -17,7 +17,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #ifdef HAVE_CVS_IDENT
-#ident "$Id: vvp_scope.c,v 1.127 2005/05/08 23:44:08 steve Exp $"
+#ident "$Id: vvp_scope.c,v 1.128 2005/05/24 01:44:28 steve Exp $"
 #endif
 
 # include  "vvp_priv.h"
@@ -567,6 +567,7 @@ static const char* draw_net_input_drive(ivl_nexus_t nex, ivl_nexus_ptr_t nptr)
 	  case IVL_LPM_RE_XNOR:
 	  case IVL_LPM_SHIFTL:
 	  case IVL_LPM_SHIFTR:
+	  case IVL_LPM_SIGN_EXT:
 	  case IVL_LPM_SUB:
 	  case IVL_LPM_MULT:
 	  case IVL_LPM_MUX:
@@ -1742,6 +1743,14 @@ static void draw_lpm_repeat(ivl_lpm_t net)
       fprintf(vvp_out, ";\n");
 }
 
+static void draw_lpm_sign_ext(ivl_lpm_t net)
+{
+      fprintf(vvp_out, "L_%p .extend/s %u, ", net,
+	      ivl_lpm_width(net));
+      draw_input_from_net(ivl_lpm_data(net,0));
+      fprintf(vvp_out, ";\n");
+}
+
 static void draw_lpm_in_scope(ivl_lpm_t net)
 {
       switch (ivl_lpm_type(net)) {
@@ -1815,6 +1824,10 @@ static void draw_lpm_in_scope(ivl_lpm_t net)
 	    draw_lpm_shiftl(net);
 	    return;
 
+	  case IVL_LPM_SIGN_EXT:
+	    draw_lpm_sign_ext(net);
+	    return;
+
 	  case IVL_LPM_UFUNC:
 	    draw_lpm_ufunc(net);
 	    return;
@@ -1942,6 +1955,9 @@ int draw_scope(ivl_scope_t net, ivl_scope_t parent)
 
 /*
  * $Log: vvp_scope.c,v $
+ * Revision 1.128  2005/05/24 01:44:28  steve
+ *  Do sign extension of structuran nets.
+ *
  * Revision 1.127  2005/05/08 23:44:08  steve
  *  Add support for variable part select.
  *