add branch listener functionaliy

have to store the branches and loop again as labels
dont neccessarily have positions yet

lib/risc/instructions/branch.rb

@@ -23,8 +23,8 @@ module Risc
     end
     alias :inspect :to_s
 
-    # if branch is implemented it must return the label it branches to
-    def branch
+    # if branch_to is implemented it must return the label it branches to
+    def branch_to
       label
     end
   end

lib/risc/position/branch_listener.rb

@@ -3,12 +3,13 @@ module Risc
   class BranchListener
 
     # initialize with the instruction listener
-    def initialize(listener)
-      @listener = listener
+    def initialize(branch)
+      @branch = branch
     end
 
-
+    # incoming position is the labels
     def position_changed(position)
+      @branch.precheck
     end
 
     # don't react to insertion, as the CodeListener will take care

lib/risc/position/instruction_listener.rb

@@ -88,16 +88,18 @@ module Risc
       raise "Not Binary Code #{code.class}" unless code.is_a?(Parfait::BinaryCode)
       raise "Must init with instruction, not nil" unless instruction
       first = nil
+      branches = []
       while(instruction)
         position = Position.get_or_create(instruction)
         first = position unless first
         position.position_listener( InstructionListener.new( code ) )
-        if instruction.respond_to?(:branch)
-#          label_pos = Position.get(instruction.branch)
-#          label_pos.position_listener( BranchListener.new(il))
-        end
+        branches << instruction if instruction.respond_to?(:branch_to)
         instruction = instruction.next
       end
+      branches.each do |branch|
+        label_pos = Position.get(branch.branch_to)
+        label_pos.position_listener( BranchListener.new(branch) )
+      end
       first
     end
   end

lib/risc/position/position.rb

@@ -220,5 +220,6 @@ module Risc
 end
 require_relative "position_listener"
 require_relative "instruction_listener"
+require_relative "branch_listener"
 require_relative "code_listener"
 require_relative "label_listener"

test/risc/position/helper.rb

@@ -37,6 +37,14 @@ module Risc
       DummyInstruction.new
     end
   end
+  class DummyBranch < Branch
+    attr_reader :precheck_called
+
+    def precheck
+      @precheck_called = true
+    end
+  end
+
   class DummyInstruction < Dummy
     include Util::List
     def initialize(nekst = nil)

test/risc/position/test_branch_listener.rb

@@ -1,14 +1,35 @@
 require_relative "helper"
+require 'minitest/mock'
 
 module Risc
-  class TestBranchListener < MiniTest::Test
+  class TestBranchListenerBooted < MiniTest::Test
+    def setup
+      DummyPlatform.boot
+      @binary = Parfait::BinaryCode.new(1)
+      @bin_pos = CodeListener.init(@binary).set(0)
+      @label = Label.new("HI","ho" , FakeAddress.new(2))
+      @branch = DummyBranch.new( "Dummy" , @label )
+      @branch.insert @label
+      InstructionListener.init(@branch , @binary)
+      @position = Position.get(@label)
+    end
+    def test_init_add_listener
+      assert_equal BranchListener , @position.event_table.values.first.last.class
+    end
+    def test_set
+      Position.get(@branch).set(12)
+      assert_equal 16 , Position.get(@label).at
+    end
+    def test_set_fires
+      Position.get(@label).set(20)
+      assert @branch.precheck_called
+    end
+  end
+  class TestBranchListenerPositioned < MiniTest::Test
     def setup
       @machine = Risc.machine.boot
       @machine.translate(:interpreter)
       @machine.position_all
     end
-
-    def test_has_init
-    end
   end
 end