change in register_names protocol

move to returning the attribute names
getting and setting can then be automated in the base class

test/risc/test_register_value1.rb

@@ -50,5 +50,15 @@ module Risc
       assert_equal Parfait::Type , reg.type.class
       assert_equal "Integer_Type" , reg.type.name
     end
+    def test_has_ssa
+      assert_nil @r0.ssa
+    end
+    def test_set_name
+      assert_equal :message , @r0.set_name(:r0)
+    end
+    def test_set_ssa
+      @r0.set_name(:r0)
+      assert_equal :message , @r0.ssa
+    end
   end
 end