NetLatch class

design_dump.cc

@@ -688,6 +688,14 @@ void NetFF::dump_node(ostream&o, unsigned ind) const
       dump_obj_attr(o, ind+4);
 }
 
+void NetLatch::dump_node(ostream&o, unsigned ind) const
+{
+      o << setw(ind) << "" << "LPM_LATCH: " << name()
+	<< " scope=" << scope_path(scope()) << endl;
+      dump_node_pins(o, ind+4);
+      dump_obj_attr(o, ind+4);
+}
+
 void NetLiteral::dump_node(ostream&o, unsigned ind) const
 {
       o << setw(ind) << "" << "constant real " << real_

emit.cc

@@ -123,6 +123,12 @@ bool NetFF::emit_node(struct target_t*tgt) const
       return true;
 }
 
+bool NetLatch::emit_node(struct target_t*tgt) const
+{
+      tgt->lpm_latch(this);
+      return true;
+}
+
 bool NetLiteral::emit_node(struct target_t*tgt) const
 {
       return tgt->net_literal(this);

functor.cc

@@ -78,6 +78,10 @@ void functor_t::lpm_ff(Design*, NetFF*)
 {
 }
 
+void functor_t::lpm_latch(Design*, NetLatch*)
+{
+}
+
 void functor_t::lpm_logic(Design*, NetLogic*)
 {
 }
@@ -219,6 +223,11 @@ void NetFF::functor_node(Design*des, functor_t*fun)
       fun->lpm_ff(des, this);
 }
 
+void NetLatch::functor_node(Design*des, functor_t*fun)
+{
+      fun->lpm_latch(des, this);
+}
+
 void NetLiteral::functor_node(Design*des, functor_t*fun)
 {
       fun->lpm_literal(des, this);

functor.h

@@ -75,6 +75,9 @@ struct functor_t {
 	/* This method is called for each FF in the design. */
       virtual void lpm_ff(class Design*des, class NetFF*);
 
+	/* This method is called for each LATCH in the design. */
+      virtual void lpm_latch(class Design*des, class NetLatch*);
+
 	/* Handle LPM combinational logic devices. */
       virtual void lpm_logic(class Design*des, class NetLogic*);
 

netlist.cc

@@ -1306,6 +1306,60 @@ const verinum& NetFF::sset_value() const
       return sset_value_;
 }
 
+/*
+ * The NetLatch class represents an LPM_LATCH device. The pinout is assigned
+ * like so:
+ *    0  -- Enable
+ *    1  -- Data
+ *    2  -- Q
+ */
+
+NetLatch::NetLatch(NetScope*s, perm_string n, unsigned width__)
+: NetNode(s, n, 3), width_(width__)
+{
+      pin_Enable().set_dir(Link::INPUT);
+      pin_Data().set_dir(Link::INPUT);
+      pin_Q().set_dir(Link::OUTPUT);
+}
+
+NetLatch::~NetLatch()
+{
+}
+
+unsigned NetLatch::width() const
+{
+      return width_;
+}
+
+Link& NetLatch::pin_Enable()
+{
+      return pin(0);
+}
+
+const Link& NetLatch::pin_Enable() const
+{
+      return pin(0);
+}
+
+Link& NetLatch::pin_Data()
+{
+      return pin(1);
+}
+
+const Link& NetLatch::pin_Data() const
+{
+      return pin(1);
+}
+
+Link& NetLatch::pin_Q()
+{
+      return pin(2);
+}
+
+const Link& NetLatch::pin_Q() const
+{
+      return pin(2);
+}
 
 NetAbs::NetAbs(NetScope*s, perm_string n, unsigned w)
 : NetNode(s, n, 2), width_(w)

netlist.h

@@ -1684,6 +1684,35 @@ class NetFF  : public NetNode {
       verinum sset_value_;
 };
 
+
+/*
+ * This class represents an LPM_LATCH device. There is no literal gate
+ * type in Verilog that maps, but gates of this type can be inferred.
+ */
+class NetLatch  : public NetNode {
+
+    public:
+      NetLatch(NetScope*s, perm_string n, unsigned vector_width);
+      ~NetLatch();
+
+      unsigned width() const;
+
+      Link& pin_Enable();
+      Link& pin_Data();
+      Link& pin_Q();
+
+      const Link& pin_Enable() const;
+      const Link& pin_Data() const;
+      const Link& pin_Q() const;
+
+      virtual void dump_node(ostream&, unsigned ind) const;
+      virtual bool emit_node(struct target_t*) const;
+      virtual void functor_node(Design*des, functor_t*fun);
+
+    private:
+      unsigned width_;
+};
+
 /*
  * This class implements a basic LPM_MULT combinational multiplier. It
  * is used as a structural representation of the * operator. The

target.cc

@@ -183,6 +183,12 @@ void target_t::lpm_ff(const NetFF*)
 	    "Unhandled NetFF." << endl;
 }
 
+void target_t::lpm_latch(const NetLatch*)
+{
+      cerr << "target (" << typeid(*this).name() << "): "
+	    "Unhandled NetLatch." << endl;
+}
+
 void target_t::lpm_mult(const NetMult*)
 {
       cerr << "target (" << typeid(*this).name() << "): "

target.h

@@ -98,6 +98,7 @@ struct target_t {
       virtual void lpm_mult(const NetMult*);
       virtual void lpm_mux(const NetMux*);
       virtual void lpm_pow(const NetPow*);
+      virtual void lpm_latch(const NetLatch*);
 
       virtual bool concat(const NetConcat*);
       virtual bool part_select(const NetPartSelect*);