Add number of registers to platform

test/risc/test_interpreter.rb

@@ -20,7 +20,7 @@ module Risc
       assert_equal :stopped , Interpreter.new(@linker).state
     end
     def test_has_regs
-      assert_equal 12 , Interpreter.new(@linker).registers.length
+      assert_equal 16 , Interpreter.new(@linker).registers.length
     end
     def test_has_r0
       assert_equal :r0 , Interpreter.new(@linker).registers.keys.first

test/risc/test_interpreter_platform.rb

@@ -17,6 +17,9 @@ module Risc
     def test_translator
       assert IdentityTranslator.new
     end
+    def test_registers
+      assert_equal 16  , @inter.num_registers
+    end
   end
   class TestIdentityTranslator < MiniTest::Test