blif support for bit selects.

tgt-blif/Makefile.in

@@ -45,7 +45,7 @@ CXXFLAGS = @WARNING_FLAGS@ @CXXFLAGS@
 LDFLAGS = @LDFLAGS@
 
 O = blif.o constants.o logic_gate.o lpm.o lpm_add.o lpm_cmp_eq.o lpm_cmp_gt.o \
-    nex_data.o
+    lpm_part_vp.o nex_data.o
 
 all: dep blif.tgt
 

tgt-blif/lpm.cc

@@ -64,37 +64,6 @@ static int print_concat(FILE*fd, ivl_lpm_t net)
       return 0;
 }
 
-/*
- * This implements the IVL_LPM_PART_VP, which is the vector-to-part
- * part select. Implement this as a .names buffer.
- */
-static int print_part_vp(FILE*fd, ivl_lpm_t net)
-{
-      int rc = 0;
-
-      ivl_nexus_t nex_out = ivl_lpm_q(net);
-      blif_nex_data_t*ned_out = blif_nex_data_t::get_nex_data(nex_out);
-
-	// Only handle bit selects.
-      assert(ned_out->get_width() == 1);
-	// Only handle constant part select base.
-      assert(ivl_lpm_data(net,1) == 0);
-
-      unsigned bit_sel = ivl_lpm_base(net);
-
-      ivl_nexus_t nex_in = ivl_lpm_data(net,0);
-      blif_nex_data_t*ned_in = blif_nex_data_t::get_nex_data(nex_in);
-
-      assert(bit_sel < ned_in->get_width());
-
-      fprintf(fd, ".names %s%s %s%s # %s:%u\n1 1\n",
-	      ned_in->get_name(), ned_in->get_name_index(bit_sel),
-	      ned_out->get_name(), ned_out->get_name_index(0),
-	      ivl_lpm_file(net), ivl_lpm_lineno(net));
-
-      return rc;
-}
-
 int print_lpm(FILE*fd, ivl_lpm_t net)
 {
       int rc = 0;
@@ -120,7 +89,7 @@ int print_lpm(FILE*fd, ivl_lpm_t net)
 	    rc += print_lpm_cmp_ne(fd, net);
 	    break;
 	  case IVL_LPM_PART_VP:
-	    rc += print_part_vp(fd, net);
+	    rc += print_lpm_part_vp(fd, net);
 	    break;
 	  case IVL_LPM_SUB:
 	    rc += print_lpm_sub(fd, net);

tgt-blif/lpm_part_vp.cc

@@ -0,0 +1,113 @@
+/*
+ * Copyright (c) 2013 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
+ *    General Public License as published by the Free Software
+ *    Foundation; either version 2 of the License, or (at your option)
+ *    any later version.
+ *
+ *    This program is distributed in the hope that it will be useful,
+ *    but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *    GNU General Public License for more details.
+ *
+ *    You should have received a copy of the GNU General Public License
+ *    along with this program; if not, write to the Free Software
+ *    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
+
+
+# include  "priv.h"
+# include  "nex_data.h"
+# include  <cassert>
+
+static int print_part_vp_mux(FILE*fd, ivl_lpm_t net);
+
+/*
+ * This implements the IVL_LPM_PART_VP, which is the vector-to-part
+ * part select. Implement this as a .names buffer.
+ */
+int print_lpm_part_vp(FILE*fd, ivl_lpm_t net)
+{
+      int rc = 0;
+
+	// If this is a non-constant bit select, then handle it
+	// elsewhere.
+      if (ivl_lpm_data(net,1) != 0)
+	    return print_part_vp_mux(fd, net);
+
+      ivl_nexus_t nex_out = ivl_lpm_q(net);
+      blif_nex_data_t*ned_out = blif_nex_data_t::get_nex_data(nex_out);
+
+	// Only handle bit selects.
+      assert(ned_out->get_width() == 1);
+	// Only handle constant part select base.
+      assert(ivl_lpm_data(net,1) == 0);
+
+      unsigned bit_sel = ivl_lpm_base(net);
+
+      ivl_nexus_t nex_in = ivl_lpm_data(net,0);
+      blif_nex_data_t*ned_in = blif_nex_data_t::get_nex_data(nex_in);
+
+      assert(bit_sel < ned_in->get_width());
+
+      fprintf(fd, ".names %s%s %s%s # %s:%u\n1 1\n",
+	      ned_in->get_name(), ned_in->get_name_index(bit_sel),
+	      ned_out->get_name(), ned_out->get_name_index(0),
+	      ivl_lpm_file(net), ivl_lpm_lineno(net));
+
+      return rc;
+}
+
+static int print_part_vp_mux(FILE*fd, ivl_lpm_t net)
+{
+	// Only handle constant part select base.
+      assert(ivl_lpm_data(net,1) != 0);
+
+      
+      ivl_nexus_t nex_out = ivl_lpm_q(net);
+      blif_nex_data_t*ned_out = blif_nex_data_t::get_nex_data(nex_out);
+
+	// Only handle bit selects.
+      assert(ned_out->get_width() == 1);
+
+      ivl_nexus_t nex_in = ivl_lpm_data(net,0);
+      blif_nex_data_t*ned_in = blif_nex_data_t::get_nex_data(nex_in);
+
+      ivl_nexus_t nex_sel = ivl_lpm_data(net,1);
+      blif_nex_data_t*ned_sel = blif_nex_data_t::get_nex_data(nex_sel);
+
+      unsigned sel_wid = ned_sel->get_width();
+      unsigned in_wid = ned_in->get_width();
+
+      assert((1U<<sel_wid) <= in_wid);
+
+      fprintf(fd, ".names ");
+      for (unsigned idx = 0 ; idx < sel_wid ; idx += 1) {
+	    fprintf(fd, " %s%s",
+		    ned_sel->get_name(), ned_sel->get_name_index(idx));
+      }
+      for (unsigned idx = 0 ; idx < in_wid ; idx += 1) {
+	    fprintf(fd, " %s%s",
+		    ned_in->get_name(), ned_in->get_name_index(idx));
+      }
+      fprintf(fd, " %s%s\n",
+	      ned_out->get_name(), ned_out->get_name_index(0));
+
+      for (unsigned idx = 0 ; idx < (1U<<sel_wid) ; idx += 1) {
+	    for (unsigned jdx = 0 ; jdx < sel_wid ; jdx += 1)
+		  fputc(idx&(1<<jdx)? '1' : '0', fd);
+
+	    for (unsigned jdx = 0 ; jdx < (1U<<sel_wid) ; jdx += 1) {
+		  if (jdx==idx)
+			fputc('1', fd);
+		  else
+			fputc('-', fd);
+	    }
+
+	    fprintf(fd, " 1\n");
+      }
+
+      return 0;
+}

tgt-blif/priv.h

@@ -36,6 +36,7 @@ extern int print_lpm_sub(FILE*fd, ivl_lpm_t net);
 extern int print_lpm_cmp_eq(FILE*fd, ivl_lpm_t net);
 extern int print_lpm_cmp_gt(FILE*fd, ivl_lpm_t net);
 extern int print_lpm_cmp_ne(FILE*fd, ivl_lpm_t net);
+extern int print_lpm_part_vp(FILE*fd, ivl_lpm_t net);
 
 /*
  * Emit all the constants for a model. This works by scanning the