sub _define{
        my  $class  =   shift   ;
        my  $type   =   shift   ;
        my  $name   =   shift   ;   
        my  $width  =   shift   ;

        if(($type ne "reg") && ($type ne "wire"))   {
            printf("\n***** ERROR: Wrong Signal type %s\n",$type);
            exit(1);
        }

        my  $object =   {   type    =>  $type   ,
                            name    =>  $name   ,
                            width   =>  $width  };
                    
        bless($object, $class);
        return $object;
    }