Generate combined input for UDP devices

Combinatorial UDPs will be implemented with a `with ... select'
statemetnt. However the input to this must be "locally static".
This patch joins the inputs into a vector which can be used as
the select expression.

tgt-vhdl/cast.cc

@@ -84,10 +84,13 @@ vhdl_expr *vhdl_expr::cast(const vhdl_type *to)
       return conv;
    }
    else if ((to->get_name() == VHDL_TYPE_UNSIGNED
-             || to->get_name() == VHDL_TYPE_SIGNED) &&
+             || to->get_name() == VHDL_TYPE_SIGNED
+             || to->get_name() == VHDL_TYPE_STD_LOGIC_VECTOR) &&
             type_->get_name() == VHDL_TYPE_STD_LOGIC) {
+
+      vhdl_expr *others = to->get_width() == 1 ? NULL : new vhdl_const_bit('0');
       vhdl_bit_spec_expr *bs =
-         new vhdl_bit_spec_expr(new vhdl_type(*to), new vhdl_const_bit('0'));
+         new vhdl_bit_spec_expr(new vhdl_type(*to), others);
       bs->add_bit(0, this);
 
       return bs;

tgt-vhdl/logic.cc

@@ -22,6 +22,7 @@
 #include "vhdl_element.hh"
 
 #include <cassert>
+#include <sstream>
 #include <iostream>
 
  
@@ -107,6 +108,36 @@ static void udp_logic(vhdl_arch *arch, ivl_net_logic_t log)
       return;
    }
 
+   // As with regular case statements, the expression in a
+   // `with .. select' statement must be "locally static".
+   // This is achieved by first combining the inputs into
+   // a temporary
+   
+   ostringstream ss;
+   ss << ivl_logic_basename(log) << "_Tmp";
+   int msb = ivl_udp_nin(udp) - 1;
+   vhdl_type *tmp_type = vhdl_type::std_logic_vector(msb, 0);
+   vhdl_signal_decl *tmp_decl =
+      new vhdl_signal_decl(ss.str().c_str(), tmp_type);
+   arch->get_scope()->add_decl(tmp_decl);
+   
+   vhdl_expr *tmp_rhs;
+   if (ivl_udp_nin(udp) == 1) {
+      tmp_rhs = nexus_to_var_ref(arch->get_scope(), ivl_logic_pin(log, 1));
+      tmp_rhs = tmp_rhs->cast(tmp_type);
+   }
+   else
+      tmp_rhs = inputs_to_expr(arch->get_scope(), VHDL_BINOP_CONCAT, log);
+
+   ss.str("");
+   ss << "Input to " << ivl_logic_basename(log) << " "
+      << ivl_udp_name(udp) << " UDP";
+   tmp_decl->set_comment(ss.str());
+
+   vhdl_var_ref *tmp_ref =
+      new vhdl_var_ref(tmp_decl->get_name().c_str(), NULL);
+   arch->add_stmt(new vhdl_cassign_stmt(tmp_ref, tmp_rhs));
+   
 }
 
 static vhdl_expr *translate_logic_inputs(vhdl_scope *scope, ivl_net_logic_t log)

tgt-vhdl/vhdl_syntax.cc

@@ -737,6 +737,7 @@ void vhdl_binop_expr::emit(std::ostream &of, int level) const
 
 vhdl_bit_spec_expr::~vhdl_bit_spec_expr()
 {
+   if (others_)
       delete others_;
 
    std::list<bit_map>::iterator it;
@@ -755,14 +756,19 @@ void vhdl_bit_spec_expr::emit(std::ostream &of, int level) const
    of << "(";
    
    std::list<bit_map>::const_iterator it;
-   for (it = bits_.begin(); it != bits_.end(); ++it) {
+   it = bits_.begin();
+   while (it != bits_.end()) {
       of << (*it).bit << " => ";
       (*it).e->emit(of, level);
+      if (++it != bits_.end())
          of << ", ";
    }
 
-   of << "others => ";
+   if (others_) {
+      of << ", others => ";
       others_->emit(of, level);
+   }
+   
    of << ")";
 }