Fix reverse bit ordered bit select in continuous assignment.

elab_net.cc

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1999-2000 Stephen Williams (steve@icarus.com)
+ * Copyright (c) 1999-2002 Stephen Williams (steve@icarus.com)
  *
  *    This source code is free software; you can redistribute it
  *    and/or modify it in source code form under the terms of the GNU
@@ -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 1.97 2002/08/21 02:28:03 steve Exp $"
+#ident "$Id: elab_net.cc,v 1.98 2002/08/31 03:48:50 steve Exp $"
 #endif
 
 # include "config.h"
@@ -1173,7 +1173,7 @@ NetNet* PEConcat::elaborate_net(Design*des, NetScope*scope,
 }
 
 /*
- * This provate method handles the special case that we have a
+ * This private method handles the special case that we have a
  * non-constant bit-select of an identifier. We already know that the
  * signal that is represented is "sig".
  */
@@ -1188,12 +1188,25 @@ NetNet* PEIdent::elaborate_net_bitmux_(Design*des, NetScope*scope,
 	/* Elaborate the selector. */
       NetNet*sel = msb_->elaborate_net(des, scope, 0, 0, 0, 0);
 
+      unsigned sig_width = sig->pin_count();
       NetMux*mux = new NetMux(scope, scope->local_hsymbol(), 1,
-			      sig->pin_count(),
+			      sig_width, sel->pin_count());
-			      sel->pin_count());
 
-      for (unsigned idx = 0 ;  idx < sig->pin_count() ;  idx += 1)
+	/* Connect the signal bits to the mux. Account for the
-	    connect(mux->pin_Data(0, idx), sig->pin(idx));
+	   direction of the numbering (lsb to msb vs. msb to lsb) by
+	   swapping the connection order. */
+
+      if (sig->msb() > sig->lsb()) {
+
+	    sel = add_to_net(des, sel, -sig->lsb());
+	    for (unsigned idx = 0 ;  idx < sig_width ;  idx += 1)
+		  connect(mux->pin_Data(0, idx), sig->pin(idx));
+      } else {
+
+	    sel = add_to_net(des, sel, -sig->msb());
+	    for (unsigned idx = 0 ;  idx < sig_width ;  idx += 1)
+		  connect(mux->pin_Data(0, idx), sig->pin(sig_width-idx-1));
+      }
 
       for (unsigned idx = 0 ;  idx < sel->pin_count() ;  idx += 1)
 	    connect(mux->pin_Sel(idx), sel->pin(idx));
@@ -2161,6 +2174,9 @@ NetNet* PEUnary::elaborate_net(Design*des, NetScope*scope,
 
 /*
  * $Log: elab_net.cc,v $
+ * Revision 1.98  2002/08/31 03:48:50  steve
+ *  Fix reverse bit ordered bit select in continuous assignment.
+ *
  * Revision 1.97  2002/08/21 02:28:03  steve
  *  Carry mux output delays.
  *

netmisc.cc

@@ -17,7 +17,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #ifdef HAVE_CVS_IDENT
-#ident "$Id: netmisc.cc,v 1.3 2002/08/12 01:35:00 steve Exp $"
+#ident "$Id: netmisc.cc,v 1.4 2002/08/31 03:48:50 steve Exp $"
 #endif
 
 # include "config.h"
@@ -26,6 +26,52 @@
 # include  "netmisc.h"
 # include  "PExpr.h"
 
+NetNet* add_to_net(Design*des, NetNet*sig, long val)
+{
+      if (val == 0)
+	    return sig;
+
+      NetScope*scope = sig->scope();
+      unsigned long abs_val = (val >= 0)? val : (-val);
+      unsigned width = sig->pin_count();
+
+      verinum val_v (abs_val, width);
+
+      NetConst*val_c = new NetConst(scope, scope->local_hsymbol(), val_v);
+
+      NetNet*val_s = new NetNet(scope, scope->local_hsymbol(),
+			      NetNet::IMPLICIT, width);
+      val_s->local_flag(true);
+
+      NetNet*res = new NetNet(scope, scope->local_hsymbol(),
+			      NetNet::IMPLICIT, width);
+      res->local_flag(true);
+
+      NetAddSub*add = new NetAddSub(scope, scope->local_hsymbol(), width);
+
+      for (unsigned idx = 0 ;  idx < width ;  idx += 1)
+	    connect(sig->pin(idx), add->pin_DataA(idx));
+
+      for (unsigned idx = 0 ;  idx < width ;  idx += 1)
+	    connect(val_c->pin(idx), add->pin_DataB(idx));
+
+      for (unsigned idx = 0 ;  idx < width ;  idx += 1)
+	    connect(val_s->pin(idx), add->pin_DataB(idx));
+
+      for (unsigned idx = 0 ;  idx < width ;  idx += 1)
+	    connect(res->pin(idx), add->pin_Result(idx));
+
+      if (val < 0)
+	    add->attribute("LPM_Direction", verinum("SUB"));
+      else
+	    add->attribute("LPM_Direction", verinum("ADD"));
+
+      des->add_node(add);
+      des->add_node(val_c);
+
+      return res;
+}
+
 
 NetExpr* elab_and_eval(Design*des, NetScope*scope, const PExpr*pe)
 {
@@ -44,6 +90,9 @@ NetExpr* elab_and_eval(Design*des, NetScope*scope, const PExpr*pe)
 
 /*
  * $Log: netmisc.cc,v $
+ * Revision 1.4  2002/08/31 03:48:50  steve
+ *  Fix reverse bit ordered bit select in continuous assignment.
+ *
  * Revision 1.3  2002/08/12 01:35:00  steve
  *  conditional ident string using autoconfig.
  *

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 1.15 2002/08/12 01:35:00 steve Exp $"
+#ident "$Id: netmisc.h,v 1.16 2002/08/31 03:48:50 steve Exp $"
 #endif
 
 # include  "netlist.h"
@@ -33,6 +33,13 @@
 extern NetExpr*pad_to_width(NetExpr*expr, unsigned wid);
 extern NetNet*pad_to_width(Design*des, NetNet*n, unsigned w);
 
+/*
+ * This function takes as input a NetNet signal and adds a constant
+ * value to it. If the val is 0, then simply return sig. Otherwise,
+ * return a new NetNet value that is the output of an addition.
+ */
+extern NetNet*add_to_net(Design*des, NetNet*sig, long val);
+
 /*
  * In some cases the lval is accessible as a pointer to the head of
  * a list of NetAssign_ objects. This function returns the width of
@@ -50,6 +57,9 @@ extern NetExpr* elab_and_eval(Design*des, NetScope*scope, const PExpr*pe);
 
 /*
  * $Log: netmisc.h,v $
+ * Revision 1.16  2002/08/31 03:48:50  steve
+ *  Fix reverse bit ordered bit select in continuous assignment.
+ *
  * Revision 1.15  2002/08/12 01:35:00  steve
  *  conditional ident string using autoconfig.
  *

tgt-vvp/vvp_process.c

@@ -17,7 +17,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #ifdef HAVE_CVS_IDENT
-#ident "$Id: vvp_process.c,v 1.65 2002/08/27 05:39:57 steve Exp $"
+#ident "$Id: vvp_process.c,v 1.66 2002/08/31 03:48:50 steve Exp $"
 #endif
 
 # include  "vvp_priv.h"
@@ -270,7 +270,8 @@ static int show_stmt_assign(ivl_statement_t net)
 
 	}
 
-	clr_vector(res);
+	if (res.base > 3)
+	      clr_vector(res);
       }
 
 
@@ -403,7 +404,8 @@ static int show_stmt_assign_nb(ivl_statement_t net)
 
 	}
 
-	clr_vector(res);
+	if (res.base > 3)
+	      clr_vector(res);
       }
 
       return 0;
@@ -1267,6 +1269,9 @@ int draw_func_definition(ivl_scope_t scope)
 
 /*
  * $Log: vvp_process.c,v $
+ * Revision 1.66  2002/08/31 03:48:50  steve
+ *  Fix reverse bit ordered bit select in continuous assignment.
+ *
  * Revision 1.65  2002/08/27 05:39:57  steve
  *  Fix l-value indexing of memories and vectors so that
  *  an unknown (x) index causes so cell to be addresses.