Support blif emit of IVL_LPM_ADD device.

tgt-blif/Makefile.in

@@ -44,7 +44,7 @@ CPPFLAGS = $(INCLUDE_PATH) @CPPFLAGS@ @DEFS@ @PICFLAG@
 CXXFLAGS = @WARNING_FLAGS@ @CXXFLAGS@
 LDFLAGS = @LDFLAGS@
 
-O = blif.o constants.o logic_gate.o lpm.o nex_data.o
+O = blif.o constants.o logic_gate.o lpm.o lpm_add.o nex_data.o
 
 all: dep blif.tgt
 

tgt-blif/lpm.cc

@@ -100,6 +100,9 @@ int print_lpm(FILE*fd, ivl_lpm_t net)
       int rc = 0;
 
       switch (ivl_lpm_type(net)) {
+	  case IVL_LPM_ADD:
+	    rc += print_lpm_add(fd, net);
+	    break;
 	  case IVL_LPM_CONCAT:
 	  case IVL_LPM_CONCATZ:
 	    rc += print_concat(fd, net);

tgt-blif/lpm_add.cc

@@ -0,0 +1,96 @@
+/*
+ * 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>
+
+/*
+ *  assign Q = A ^ B ^ Cin;
+ *  assign Cout = A&B | A&Cin | B&Cin;
+ */
+int print_lpm_add(FILE*fd, ivl_lpm_t net)
+{
+      fprintf(fd, "# %s:%u: IVL_LPM_ADD: width=%u\n",
+	      ivl_lpm_file(net), ivl_lpm_lineno(net), ivl_lpm_width(net));
+
+      ivl_nexus_t q_nex = ivl_lpm_q(net);
+      ivl_nexus_t a_nex = ivl_lpm_data(net,0);
+      ivl_nexus_t b_nex = ivl_lpm_data(net,1);
+
+      blif_nex_data_t*q_ned = blif_nex_data_t::get_nex_data(q_nex);
+      blif_nex_data_t*a_ned = blif_nex_data_t::get_nex_data(a_nex);
+      blif_nex_data_t*b_ned = blif_nex_data_t::get_nex_data(b_nex);
+
+      assert(ivl_lpm_width(net) == q_ned->get_width());
+      assert(ivl_lpm_width(net) == a_ned->get_width());
+      assert(ivl_lpm_width(net) == b_ned->get_width());
+
+	// Q[0] = A[0] ^ B[0]
+      fprintf(fd, ".names %s%s %s%s %s%s\n"
+	      "10 1\n"
+	      "01 1\n",
+	      a_ned->get_name(), a_ned->get_name_index(0),
+	      b_ned->get_name(), b_ned->get_name_index(0),
+	      q_ned->get_name(), q_ned->get_name_index(0));
+
+	// Special case: If this is a 1-bit adder, then all we need is
+	// the XOR above. We're done.
+      if (ivl_lpm_width(net) == 1)
+	    return 0;
+
+	// Cout[0] = A[0] & B[0]
+      fprintf(fd, ".names %s%s %s%s %s%s/cout\n"
+	      "11 1\n",
+	      a_ned->get_name(), a_ned->get_name_index(0),
+	      b_ned->get_name(), b_ned->get_name_index(0),
+	      q_ned->get_name(), q_ned->get_name_index(0));
+
+      for (unsigned idx = 1 ; idx < ivl_lpm_width(net) ; idx += 1) {
+	    char cin[128];
+	    snprintf(cin, sizeof cin, "%s%s/cout",
+		     q_ned->get_name(), q_ned->get_name_index(idx-1));
+
+	      // Q[idx] = A[idx] ^ B[idx] ^ cin
+	    fprintf(fd, ".names %s%s %s%s %s %s%s\n"
+		    "001 1\n"
+		    "010 1\n"
+		    "100 1\n"
+		    "111 1\n",
+		    a_ned->get_name(), a_ned->get_name_index(idx),
+		    b_ned->get_name(), b_ned->get_name_index(idx),
+		    cin,
+		    q_ned->get_name(), q_ned->get_name_index(idx));
+
+	    if ((idx+1) == ivl_lpm_width(net))
+		  continue;
+
+	      // Cout[idx] = A[idx]&B[idx] | A[idx]&Cin | B[idx]&Cin
+	    fprintf(fd, ".names %s%s %s%s %s %s%s/cout\n"
+		    "011 1\n"
+		    "101 1\n"
+		    "11- 1\n",
+		    a_ned->get_name(), a_ned->get_name_index(idx),
+		    b_ned->get_name(), b_ned->get_name_index(idx),
+		    cin,
+		    q_ned->get_name(), q_ned->get_name_index(idx));
+      }
+
+      return 0;
+}

tgt-blif/priv.h

@@ -31,6 +31,7 @@ extern int blif_errors;
 extern int print_logic_gate(FILE*fd, ivl_net_logic_t net);
 
 extern int print_lpm(FILE*fd, ivl_lpm_t net);
+extern int print_lpm_add(FILE*fd, ivl_lpm_t net);
 
 /*
  * Emit all the constants for a model. This works by scanning the