diff --git a/Module.h b/Module.h
index 3222a2838..68e841d65 100644
--- a/Module.h
+++ b/Module.h
@@ -75,16 +75,29 @@ class Module : public PScope, public LineInfo {
 
       NetNet::Type default_nettype;
 
+      struct range_t {
+	      // True if this is an exclude
+	    bool exclude_flag;
+	      // lower bound
+	    bool low_open_flag;
+	    PExpr*low_expr;
+	      // upper bound
+	    bool high_open_flag;
+	    PExpr*high_expr;
+	      // Next range description in list
+	    struct range_t*next;
+      };
+
 	/* The module has parameters that are evaluated when the
 	   module is elaborated. During parsing, I put the parameters
 	   into this map. */
-      struct param_expr_t {
+      struct param_expr_t : public LineInfo {
 	    PExpr*expr;
 	    PExpr*msb;
 	    PExpr*lsb;
-	    perm_string file;
-	    unsigned lineno;
 	    bool signed_flag;
+	      // If there are range constrants, list them here
+	    range_t*range;
       };
       map<perm_string,param_expr_t>parameters;
       map<perm_string,param_expr_t>localparams;
@@ -158,8 +171,7 @@ class Module : public PScope, public LineInfo {
       map<perm_string,PFunction*> funcs_;
 
       static void elaborate_parm_item_(perm_string name, const param_expr_t&cur,
-				       Design*des, NetScope*scope,
-				       perm_string file, unsigned lineno);
+				       Design*des, NetScope*scope);
 
     private: // Not implemented
       Module(const Module&);
diff --git a/elab_scope.cc b/elab_scope.cc
index 175d0474c..725785a32 100644
--- a/elab_scope.cc
+++ b/elab_scope.cc
@@ -45,8 +45,7 @@
 # include  <assert.h>
 
 void Module::elaborate_parm_item_(perm_string name, const param_expr_t&cur,
-				  Design*des, NetScope*scope,
-				  perm_string file, unsigned lineno)
+				  Design*des, NetScope*scope)
 {
       PExpr*ex = cur.expr;
       assert(ex);
@@ -81,8 +80,8 @@ void Module::elaborate_parm_item_(perm_string name, const param_expr_t&cur,
 	    signed_flag = val->has_sign();
       }
 
-      val = scope->set_parameter(name, val,
-				 msb, lsb, signed_flag, file, lineno);
+      val = scope->set_parameter(name, val, msb, lsb, signed_flag,
+				 cur.get_file(), cur.get_lineno());
       assert(val);
       delete val;
 }
@@ -121,7 +120,8 @@ bool Module::elaborate_scope(Design*des, NetScope*scope,
 	    tmp->cast_signed( (*cur).second.signed_flag );
 
 	    scope->set_parameter((*cur).first, tmp, 0, 0, false,
-	                         (*cur).second.file, (*cur).second.lineno);
+	                         (*cur).second.get_file(),
+				 (*cur).second.get_lineno());
       }
 
       for (mparm_it_t cur = localparams.begin()
@@ -133,7 +133,8 @@ bool Module::elaborate_scope(Design*des, NetScope*scope,
 		  tmp->cast_signed( (*cur).second.signed_flag );
 
 	    scope->set_parameter((*cur).first, tmp, 0, 0, false,
-	                         (*cur).second.file, (*cur).second.lineno);
+	                         (*cur).second.get_file(),
+				 (*cur).second.get_lineno());
       }
 
 
@@ -145,8 +146,7 @@ bool Module::elaborate_scope(Design*des, NetScope*scope,
       for (mparm_it_t cur = parameters.begin()
 		 ; cur != parameters.end() ;  cur ++) {
 
-	    elaborate_parm_item_((*cur).first, (*cur).second, des, scope,
-	                         (*cur).second.file, (*cur).second.lineno);
+	    elaborate_parm_item_((*cur).first, (*cur).second, des, scope);
       }
 
 	/* run parameter replacements that were collected from the
@@ -178,8 +178,7 @@ bool Module::elaborate_scope(Design*des, NetScope*scope,
       for (mparm_it_t cur = localparams.begin()
 		 ; cur != localparams.end() ;  cur ++) {
 
-	    elaborate_parm_item_((*cur).first, (*cur).second, des, scope,
-	                         (*cur).second.file, (*cur).second.lineno);
+	    elaborate_parm_item_((*cur).first, (*cur).second, des, scope);
       }
 
 	// Run through the defparams for this module, elaborate the
diff --git a/lexor_keyword.gperf b/lexor_keyword.gperf
index 5d8c05035..980b33c89 100644
--- a/lexor_keyword.gperf
+++ b/lexor_keyword.gperf
@@ -79,6 +79,7 @@ hypot,		GN_KEYWORDS_VAMS_2_3,	K_hypot
 idt_nature,	GN_KEYWORDS_VAMS_2_3,	K_idt_nature
 if,		GN_KEYWORDS_1364_1995,	K_if
 ifnone,		GN_KEYWORDS_1364_1995,	K_ifnone
+inf,		GN_KEYWORDS_VAMS_2_3,	K_inf
 initial,	GN_KEYWORDS_1364_1995,	K_initial
 inout,		GN_KEYWORDS_1364_1995,	K_inout
 input,		GN_KEYWORDS_1364_1995,	K_input
diff --git a/parse.y b/parse.y
index d375ea19c..0ec6c273b 100644
--- a/parse.y
+++ b/parse.y
@@ -156,6 +156,7 @@ static PECallFunction*make_call_function(perm_string tn, PExpr*arg1, PExpr*arg2)
       svector<lgate>*gates;
 
       Module::port_t *mport;
+      Module::range_t* value_range;
       svector<Module::port_t*>*mports;
 
       named_pexpr_t*named_pexpr;
@@ -213,7 +214,7 @@ static PECallFunction*make_call_function(perm_string tn, PExpr*arg1, PExpr*arg2)
 %token K_endprimitive K_endspecify K_endtable K_endtask K_event
 %token K_exclude K_exp K_floor K_flow K_from
 %token K_for K_force K_forever K_fork K_function K_generate K_genvar
-%token K_ground K_highz0 K_highz1 K_hypot K_idt_nature K_if K_ifnone
+%token K_ground K_highz0 K_highz1 K_hypot K_idt_nature K_if K_ifnone K_inf
 %token K_initial K_inout K_input K_integer K_join K_large K_ln K_localparam
 %token K_log K_logic K_macromodule K_max
 %token K_medium K_min K_module K_nand K_nature K_negedge
@@ -235,6 +236,7 @@ static PECallFunction*make_call_function(perm_string tn, PExpr*arg1, PExpr*arg2)
 
 %token KK_attribute
 
+%type <flag>    from_exclude
 %type <number>  number
 %type <flag>    signed_opt udp_reg_opt edge_operator
 %type <drive>   drive_strength drive_strength_opt dr_strength0 dr_strength1
@@ -256,6 +258,9 @@ static PECallFunction*make_call_function(perm_string tn, PExpr*arg1, PExpr*arg2)
 %type <mport> port port_opt port_reference port_reference_list
 %type <mport> port_declaration
 %type <mports> list_of_ports module_port_list_opt list_of_port_declarations
+%type <value_range> parameter_value_range parameter_value_ranges
+%type <value_range> parameter_value_ranges_opt
+%type <expr> value_range_expression
 
 %type <wires> task_item task_item_list task_item_list_opt
 %type <wires> task_port_item task_port_decl task_port_decl_list
@@ -2375,22 +2380,43 @@ parameter_assign_list
 	;
 
 parameter_assign
-	: IDENTIFIER '=' expression
-		{ PExpr*tmp = $3;
-		  if (!pform_expression_is_constant(tmp)) {
-			yyerror(@3, "error: parameter value "
-			            "must be a constant expression.");
-			delete tmp;
-			tmp = 0;
-		  } else {
-			pform_set_parameter(lex_strings.make($1),
-					    active_signed,
-					    active_range, tmp,
-					    @1.text, @1.first_line);
-		  }
-		  delete[]$1;
-		}
-	;
+  : IDENTIFIER '=' expression parameter_value_ranges_opt
+      { PExpr*tmp = $3;
+	pform_set_parameter(@1, lex_strings.make($1),
+			    active_signed, active_range, tmp, $4);
+	delete[]$1;
+      }
+  ;
+
+parameter_value_ranges_opt : parameter_value_ranges { $$ = $1; } | { $$ = 0; } ;
+
+parameter_value_ranges
+  : parameter_value_ranges parameter_value_range
+      { $$ = $2; $$->next = $1; }
+  | parameter_value_range
+      { $$ = $1; $$->next = 0; }
+  ;
+
+parameter_value_range
+  : from_exclude '[' value_range_expression ':' value_range_expression ']'
+      { $$ = pform_parameter_value_range($1, false, $3, false, $5); }
+  | from_exclude '[' value_range_expression ':' value_range_expression ')'
+      { $$ = pform_parameter_value_range($1, false, $3, true, $5); }
+  | from_exclude '(' value_range_expression ':' value_range_expression ']'
+      { $$ = pform_parameter_value_range($1, true, $3, false, $5); }
+  | from_exclude '(' value_range_expression ':' value_range_expression ')'
+      { $$ = pform_parameter_value_range($1, true, $3, true, $5); }
+    /* | K_exclude  expression */
+  ;
+
+value_range_expression
+  : expression { $$ = $1; }
+  | K_inf { $$ = 0; }
+  | '+' K_inf { $$ = 0; }
+  | '-' K_inf { $$ = 0; }
+  ;
+
+from_exclude : K_from { $$ = false; } | K_exclude { $$ = true; } ;
 
   /* Localparam assignments and assignment lists are broken into
      separate BNF so that I can call slightly different parameter
@@ -2406,10 +2432,9 @@ localparam_assign
 			delete tmp;
 			tmp = 0;
 		  } else {
-			pform_set_localparam(lex_strings.make($1),
+			pform_set_localparam(@1, lex_strings.make($1),
 					     active_signed,
-					     active_range, tmp,
-					     @1.text, @1.first_line);
+					     active_range, tmp);
 		  }
 		  delete[]$1;
 		}
diff --git a/pform.cc b/pform.cc
index f964a85ca..22f4e9176 100644
--- a/pform.cc
+++ b/pform.cc
@@ -1634,50 +1634,69 @@ void pform_set_reg_idx(perm_string name, PExpr*l, PExpr*r)
       cur->set_memory_idx(l, r);
 }
 
-void pform_set_parameter(perm_string name, bool signed_flag,
+Module::range_t* pform_parameter_value_range(bool exclude_flag,
+					     bool low_open, PExpr*low_expr,
+					     bool hig_open, PExpr*hig_expr)
+{
+      Module::range_t*tmp = new Module::range_t;
+      tmp->exclude_flag = exclude_flag;
+      tmp->low_open_flag = low_open;
+      tmp->low_expr = low_expr;
+      tmp->high_open_flag = hig_open;
+      tmp->high_expr = hig_expr;
+      tmp->next = 0;
+      return tmp;
+}
+
+void pform_set_parameter(const struct vlltype&loc,
+			 perm_string name, bool signed_flag,
 			 svector<PExpr*>*range, PExpr*expr,
-			 const char*file, unsigned lineno)
+			 Module::range_t*value_range)
 {
       assert(expr);
-      pform_cur_module->parameters[name].expr = expr;
+      Module::param_expr_t&parm = pform_cur_module->parameters[name];
+      FILE_NAME(&parm, loc);
+
+      parm.expr = expr;
 
       if (range) {
 	    assert(range->count() == 2);
 	    assert((*range)[0]);
 	    assert((*range)[1]);
-	    pform_cur_module->parameters[name].msb = (*range)[0];
-	    pform_cur_module->parameters[name].lsb = (*range)[1];
+	    parm.msb = (*range)[0];
+	    parm.lsb = (*range)[1];
       } else {
-	    pform_cur_module->parameters[name].msb = 0;
-	    pform_cur_module->parameters[name].lsb = 0;
+	    parm.msb = 0;
+	    parm.lsb = 0;
       }
-      pform_cur_module->parameters[name].signed_flag = signed_flag;
-      pform_cur_module->parameters[name].file = filename_strings.make(file);
-      pform_cur_module->parameters[name].lineno = lineno;
+      parm.signed_flag = signed_flag;
+      parm.range = value_range;
 
       pform_cur_module->param_names.push_back(name);
 }
 
-void pform_set_localparam(perm_string name, bool signed_flag,
-			  svector<PExpr*>*range, PExpr*expr,
-			  const char*file, unsigned lineno)
+void pform_set_localparam(const struct vlltype&loc,
+			  perm_string name, bool signed_flag,
+			  svector<PExpr*>*range, PExpr*expr)
 {
       assert(expr);
-      pform_cur_module->localparams[name].expr = expr;
+      Module::param_expr_t&parm = pform_cur_module->localparams[name];
+      FILE_NAME(&parm, loc);
+
+      parm.expr = expr;
 
       if (range) {
 	    assert(range->count() == 2);
 	    assert((*range)[0]);
 	    assert((*range)[1]);
-	    pform_cur_module->localparams[name].msb = (*range)[0];
-	    pform_cur_module->localparams[name].lsb = (*range)[1];
+	    parm.msb = (*range)[0];
+	    parm.lsb = (*range)[1];
       } else {
-	    pform_cur_module->localparams[name].msb  = 0;
-	    pform_cur_module->localparams[name].lsb  = 0;
+	    parm.msb  = 0;
+	    parm.lsb  = 0;
       }
-      pform_cur_module->localparams[name].signed_flag = signed_flag;
-      pform_cur_module->localparams[name].file = filename_strings.make(file);
-      pform_cur_module->localparams[name].lineno = lineno;
+      parm.signed_flag = signed_flag;
+      parm.range = 0;
 }
 
 void pform_set_specparam(perm_string name, PExpr*expr)
diff --git a/pform.h b/pform.h
index 3e971ecee..f5b18c344 100644
--- a/pform.h
+++ b/pform.h
@@ -266,16 +266,20 @@ extern void pform_set_attrib(perm_string name, perm_string key,
 extern void pform_set_type_attrib(perm_string name, const string&key,
 				  char*value);
 
-extern void pform_set_parameter(perm_string name,
+extern Module::range_t* pform_parameter_value_range(bool exclude_flag,
+						    bool low_open, PExpr*low_expr,
+						    bool hig_open, PExpr*hig_expr);
+
+extern void pform_set_parameter(const struct vlltype&loc,
+				perm_string name,
 				bool signed_flag,
 				svector<PExpr*>*range,
-				PExpr*expr,
-				const char*file, unsigned lineno);
-extern void pform_set_localparam(perm_string name,
+				PExpr*expr, Module::range_t*value_range);
+extern void pform_set_localparam(const struct vlltype&loc,
+				 perm_string name,
 				 bool signed_flag,
 				 svector<PExpr*>*range,
-				 PExpr*expr,
-				 const char*file, unsigned lineno);
+				 PExpr*expr);
 extern void pform_set_defparam(const pform_name_t&name, PExpr*expr);
 
 /*
diff --git a/pform_dump.cc b/pform_dump.cc
index da55b307f..bcc973031 100644
--- a/pform_dump.cc
+++ b/pform_dump.cc
@@ -1002,9 +1002,34 @@ void Module::dump(ostream&out) const
 		      << *(*cur).second.lsb << "] ";
 	    out << (*cur).first << " = ";
 	    if ((*cur).second.expr)
-		  out << *(*cur).second.expr << ";" << endl;
+		  out << *(*cur).second.expr;
 	    else
-		  out << "/* ERROR */;" << endl;
+		  out << "/* ERROR */";
+	    for (Module::range_t*tmp = (*cur).second.range
+		       ; tmp ; tmp = tmp->next) {
+		  if (tmp->exclude_flag)
+			out << " exclude ";
+		  else
+			out << " from ";
+		  if (tmp->low_open_flag)
+			out << "(";
+		  else
+			out << "[";
+		  if (tmp->low_expr)
+			out << *(tmp->low_expr);
+		  else
+			out << "<>";
+		  out << ":";
+		  if (tmp->high_expr)
+			out << *(tmp->high_expr);
+		  else
+			out << "<>";
+		  if (tmp->high_open_flag)
+			out << ")";
+		  else
+			out << "]";
+	    }
+	    out << ";" << endl;
       }
 
       for (parm_iter_t cur = localparams.begin()