Refactor support function code a bit

tgt-vhdl/cast.cc

@@ -48,19 +48,19 @@ vhdl_expr *vhdl_expr::cast(const vhdl_type *to)
       }
       else if (type_->get_name() == VHDL_TYPE_UNSIGNED) {
          // Need to use a support function for this conversion
-         require_support_function<unsigned_to_boolean>();
+         require_support_function(SF_UNSIGNED_TO_BOOLEAN);
 
          vhdl_fcall *conv =
-            new vhdl_fcall(unsigned_to_boolean::function_name(),
+            new vhdl_fcall(support_function::function_name(SF_UNSIGNED_TO_BOOLEAN),
                            vhdl_type::boolean());
          conv->add_expr(this);
          return conv;
       }
       else if (type_->get_name() == VHDL_TYPE_SIGNED) {
-         require_support_function<signed_to_boolean>();
+         require_support_function(SF_SIGNED_TO_BOOLEAN);
 
          vhdl_fcall *conv =
-            new vhdl_fcall(signed_to_boolean::function_name(),
+            new vhdl_fcall(support_function::function_name(SF_SIGNED_TO_BOOLEAN),
                            vhdl_type::boolean());
          conv->add_expr(this);
          return conv;
@@ -77,10 +77,11 @@ vhdl_expr *vhdl_expr::cast(const vhdl_type *to)
    }
    else if (to->get_name() == VHDL_TYPE_STD_LOGIC &&
             type_->get_name() == VHDL_TYPE_BOOLEAN) {
-      // Verilog assumes active-high logic and there
-      // is a special routine in verilog_support.vhd
-      // to do this for us
-      vhdl_fcall *ah = new vhdl_fcall("Active_High", vhdl_type::std_logic());
+      require_support_function(SF_BOOLEAN_TO_LOGIC);
+      
+      vhdl_fcall *ah =
+         new vhdl_fcall(support_function::function_name(SF_BOOLEAN_TO_LOGIC),
+                        vhdl_type::std_logic());
       ah->add_expr(this);
 
       return ah;

tgt-vhdl/support.cc

@@ -23,28 +23,82 @@
 
 #include <cassert>
 
-void unsigned_to_boolean::emit(std::ostream &of, int level) const
+void require_support_function(support_function_t f)
 {
-   of << "function " << function_name()
-      << "(X : unsigned) return Boolean is";
+   vhdl_scope *scope = get_active_entity()->get_arch()->get_scope();
+   if (!scope->have_declared(support_function::function_name(f)))
+      scope->add_decl(new support_function(f));
+}
+
+const char *support_function::function_name(support_function_t type)
+{
+   switch (type) {
+   case SF_UNSIGNED_TO_BOOLEAN:
+      return "Unsigned_To_Boolean";
+   case SF_SIGNED_TO_BOOLEAN:
+      return "Signed_To_Boolean";
+   case SF_BOOLEAN_TO_LOGIC:
+      return "Boolean_To_Logic";
+   default:
+      assert(false);
+   }
+}
+
+vhdl_type *support_function::function_type(support_function_t type)
+{
+   switch (type) {
+   case SF_UNSIGNED_TO_BOOLEAN:
+      return vhdl_type::boolean();
+   case SF_SIGNED_TO_BOOLEAN:
+      return vhdl_type::boolean();
+   case SF_BOOLEAN_TO_LOGIC:
+      return vhdl_type::std_logic();
+   default:
+      assert(false);
+   }
+}
+
+void support_function::emit(std::ostream &of, int level) const
+{
+   of << "function " << function_name(type_);
+   
+   switch (type_) {
+   case SF_UNSIGNED_TO_BOOLEAN:
+      of << "(X : unsigned) return Boolean is";
       newline(of, level);
       of << "begin";
       newline(of, indent(level));
       of << "return X /= To_Unsigned(0, X'Length);";
       newline(of, level);
-   of << "end function;";
-   newline(of, level);
-}
-
-void signed_to_boolean::emit(std::ostream &of, int level) const
-{
-   of << "function " << function_name()
-      << "(X : signed) return Boolean is";
+      break;
+   case SF_SIGNED_TO_BOOLEAN:
+      of << "(X : signed) return Boolean is";
       newline(of, level);
       of << "begin";
       newline(of, indent(level));
       of << "return X /= To_Signed(0, X'Length);";
       newline(of, level);
+      break;
+   case SF_BOOLEAN_TO_LOGIC:
+      of << "(B : Boolean) return std_logic is";
+      newline(of, level);
+      of << "begin";
+      newline(of, indent(level));
+      of << "if B then";
+      newline(of, indent(indent(level)));
+      of << "return '1'";
+      newline(of, indent(level));
+      of << "else";
+      newline(of, indent(indent(level)));
+      of << "return '0'";
+      newline(of, indent(level));
+      of << "end if;";
+      newline(of, level);
+      break;
+   default:
+      assert(false);
+   }
+   
    of << "end function;";
    newline(of, level);
 }

tgt-vhdl/support.hh

@@ -23,23 +23,23 @@
 
 #include "vhdl_syntax.hh"
 
-class unsigned_to_boolean : public vhdl_function {
-public:
-   unsigned_to_boolean()
-      : vhdl_function(function_name(), vhdl_type::boolean()) {}
-   void emit(std::ostream &of, int level) const;
-
-   static const char *function_name() { return "Unsigned_To_Boolean"; }
+enum support_function_t {
+   SF_UNSIGNED_TO_BOOLEAN,
+   SF_SIGNED_TO_BOOLEAN,
+   SF_BOOLEAN_TO_LOGIC,
 };
 
-
-class signed_to_boolean : public vhdl_function {
+class support_function : public vhdl_function {
 public:
-   signed_to_boolean()
-      : vhdl_function(function_name(), vhdl_type::boolean()) {}
+   support_function(support_function_t type)
+      : vhdl_function(function_name(type), function_type(type)),
+        type_(type) {}
    void emit(std::ostream &of, int level) const;
+   static const char *function_name(support_function_t type);
+   static vhdl_type *function_type(support_function_t type);
 
-   static const char *function_name() { return "Signed_To_Boolean"; }
+private:
+   support_function_t type_;
 };
 
 #endif

tgt-vhdl/vhdl_target.h

@@ -7,6 +7,8 @@
 #include "vhdl_syntax.hh"
 #include "vhdl_type.hh"
 
+#include "support.hh"
+
 #include <string>
 
 using namespace std;
@@ -41,13 +43,7 @@ ivl_signal_t find_signal_named(const string &name, const vhdl_scope *scope);
 int draw_stask_display(vhdl_procedural *proc, stmt_container *container,
                        ivl_statement_t stmt, bool newline = true);
 
-template <class T>
-void require_support_function()
-{
-   vhdl_scope *scope = get_active_entity()->get_arch()->get_scope();
-   if (!scope->have_declared(T::function_name()))
-      scope->add_decl(new T);
-}
+void require_support_function(support_function_t f);
 
 #endif /* #ifndef INC_VHDL_TARGET_H */