Added support for LPM latches to vvp.

vvp/Makefile.in

@@ -72,7 +72,7 @@ V = vpi_modules.o vpi_callback.o vpi_cobject.o vpi_const.o vpi_darray.o \
     vpip_to_dec.o vpip_format.o vvp_vpi.o
 
 O = main.o parse.o parse_misc.o lexor.o arith.o array_common.o array.o bufif.o compile.o \
-    concat.o dff.o class_type.o enum_type.o extend.o file_line.o npmos.o part.o \
+    concat.o dff.o class_type.o enum_type.o extend.o file_line.o latch.o npmos.o part.o \
     permaheap.o reduce.o resolv.o \
     sfunc.o stop.o \
     substitute.o \

vvp/compile.h

@@ -1,7 +1,7 @@
 #ifndef IVL_compile_H
 #define IVL_compile_H
 /*
- * Copyright (c) 2001-2014 Stephen Williams (steve@icarus.com)
+ * Copyright (c) 2001-2016 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
@@ -225,6 +225,10 @@ extern void compile_dff_aset(char*label, unsigned width, bool negedge,
 			     struct symb_s arg_a,
 			     char*asc_value);
 
+extern void compile_latch(char*label, unsigned width,
+			  struct symb_s arg_d,
+			  struct symb_s arg_e);
+
 extern void compile_enum2_type(char*label, long width, bool signed_flag,
 			      std::list<struct enum_name_s>*names);
 extern void compile_enum4_type(char*label, long width, bool signed_flag,

vvp/latch.cc

@@ -0,0 +1,88 @@
+/*
+ * Copyright (c) 2016 Martin Whitaker (icarus@martin-whitaker.me.uk)
+ *
+ *    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  "compile.h"
+# include  "schedule.h"
+# include  "latch.h"
+# include  <climits>
+# include  <cstdio>
+# include  <cassert>
+# include  <cstdlib>
+# include  <iostream>
+
+/* We need to ensure an initial output value is propagated. This is
+   achieved by scheduling an initial value to be sent to port 3. Any
+   value received on port 3 will propagate an initial value of 'bx. */
+
+vvp_latch::vvp_latch(unsigned width)
+: en_(BIT4_X), d_(width, BIT4_X)
+{
+}
+
+vvp_latch::~vvp_latch()
+{
+}
+
+void vvp_latch::recv_vec4(vvp_net_ptr_t port, const vvp_vector4_t&bit,
+                          vvp_context_t)
+{
+      vvp_bit4_t tmp;
+
+      switch (port.port()) {
+
+	  case 0: // D
+	    d_ = bit;
+	    if (en_ == BIT4_1)
+		  schedule_propagate_vector(port.ptr(), 0, d_);
+	    break;
+
+	  case 1: // EN
+	    assert(bit.size() == 1);
+	    tmp = en_;
+	    en_ = bit.value(0);
+	    if (en_ == BIT4_1 && tmp != BIT4_1)
+		  schedule_propagate_vector(port.ptr(), 0, d_);
+	    break;
+
+	  case 2:
+	    assert(0);
+	    break;
+
+	  case 3:
+	    port.ptr()->send_vec4(vvp_vector4_t(d_.size(), BIT4_X), 0);
+	    break;
+      }
+}
+
+void compile_latch(char*label, unsigned width,
+		   struct symb_s arg_d,
+		   struct symb_s arg_e)
+{
+      vvp_net_t*ptr = new vvp_net_t;
+      vvp_latch*fun = new vvp_latch(width);
+
+      ptr->fun = fun;
+      define_functor_symbol(label, ptr);
+      free(label);
+      input_connect(ptr, 0, arg_d.text);
+      input_connect(ptr, 1, arg_e.text);
+
+      vvp_vector4_t init_val = vvp_vector4_t(1, BIT4_1);
+      schedule_init_vector(vvp_net_ptr_t(ptr,3), init_val);
+}

vvp/latch.h

@@ -0,0 +1,45 @@
+#ifndef IVL_latch_H
+#define IVL_latch_H
+/*
+ * Copyright (c) 2016 Martin Whitaker (icarus@martin-whitaker.me.uk)
+ *
+ *    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  "vvp_net.h"
+
+/*
+ * The vvp_latch implements an arbitrary width D-type transparent latch.
+ * The latch enable is a single bit. Ports are:
+ *
+ *   port-0:  D input
+ *   port-1:  EN input
+ */
+class vvp_latch : public vvp_net_fun_t {
+
+    public:
+      explicit vvp_latch(unsigned width);
+      ~vvp_latch();
+
+      void recv_vec4(vvp_net_ptr_t port, const vvp_vector4_t&bit,
+                     vvp_context_t);
+
+    private:
+      vvp_bit4_t en_;
+      vvp_vector4_t d_;
+};
+
+#endif /* IVL_latch_H */

vvp/lexor.lex

@@ -4,7 +4,7 @@
 
 %{
 /*
- * Copyright (c) 2001-2012 Stephen Williams (steve@icarus.com)
+ * Copyright (c) 2001-2016 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
@@ -168,6 +168,7 @@ static char* strdupnew(char const *str)
 ".functor"  { return K_FUNCTOR; }
 ".import"   { return K_IMPORT; }
 ".island"   { return K_ISLAND; }
+".latch"    { return K_LATCH; }
 ".modpath"  { return K_MODPATH; }
 ".net"      { return K_NET; }
 ".net/2s"   { return K_NET_2S; }

vvp/parse.y

@@ -1,7 +1,7 @@
 
 %{
 /*
- * Copyright (c) 2001-2015 Stephen Williams (steve@icarus.com)
+ * Copyright (c) 2001-2016 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
@@ -86,7 +86,7 @@ static struct __vpiModPath*modpath_dst = 0;
 %token K_CONCAT K_CONCAT8 K_DEBUG K_DELAY K_DFF_N K_DFF_N_ACLR
 %token K_DFF_N_ASET K_DFF_P K_DFF_P_ACLR K_DFF_P_ASET
 %token K_ENUM2 K_ENUM2_S K_ENUM4 K_ENUM4_S K_EVENT K_EVENT_OR
-%token K_EXPORT K_EXTEND_S K_FUNCTOR K_IMPORT K_ISLAND K_MODPATH
+%token K_EXPORT K_EXTEND_S K_FUNCTOR K_IMPORT K_ISLAND K_LATCH K_MODPATH
 %token K_NET K_NET_S K_NET_R K_NET_2S K_NET_2U
 %token K_NET8 K_NET8_2S K_NET8_2U K_NET8_S
 %token K_PARAM_STR K_PARAM_L K_PARAM_REAL K_PART K_PART_PV
@@ -522,6 +522,11 @@ statement
   | T_LABEL K_DFF_P_ASET T_NUMBER symbol ',' symbol ',' symbol ',' symbol ',' T_SYMBOL ';'
       { compile_dff_aset($1, $3, false, $4, $6, $8, $10, $12); }
 
+  /* LATCH nodes have an output and take 2 inputs. */
+
+  | T_LABEL K_LATCH T_NUMBER symbol ',' symbol ';'
+      { compile_latch($1, $3, $4, $6); }
+
   /* The various reduction operator nodes take a single input. */
 
         | T_LABEL K_REDUCE_AND symbol ';'