start on redoing instruction positions

using insruction listeners (wip)

lib/arm/instructions/instruction.rb

@@ -25,7 +25,7 @@ module Arm
       super
       my_pos = Risc::Position.get(self)
       # set my position to set next according to rules
-      Risc::Position.set(  self , my_pos.at , my_pos.binary) 
+      Risc::Position::InstructionListener.init(instruction , my_pos.get_code)
     end
   end
 end

lib/risc/machine.rb

@@ -117,14 +117,15 @@ module Risc
     #
     # start at code_start.
     def position_code(code_start)
-      prev = nil
+      prev_code = nil
       Parfait.object_space.types.values.each do |type|
         next unless type.methods
         type.methods.each_method do |method|
-          last = Position::CodeListener.init(method.binary , code_start)
+          last_code = Position::CodeListener.init(method.binary , code_start)
-          last.register_event(:position_changed , prev.object) if prev
+          Position::InstructionListener.init(method.cpu_instructions, method.binary)
-          prev = last
+          last_code.register_event(:position_changed , prev_code.object) if prev_code
-          code_start = last.next_slot
+          prev_code = last_code
+          code_start = last_code.next_slot
         end
       end
       #Position.set( first_method.cpu_instructions, code_start + Parfait::BinaryCode.byte_offset , first_method.binary)

lib/risc/position/instruction_listener.rb

@@ -14,11 +14,10 @@ module Risc
     # When propagating positions we have to see that the next position assembles into
     # the same BinaryCode, or else move it and the code along
     #
-    class InstructionPosition < ObjectPosition
+    class InstructionListener
       attr_reader :instruction , :binary
       def initialize(instruction , binary)
         pos = 0
-        super(instruction)
         @instruction = instruction
         @binary = binary
       end
@@ -50,21 +49,26 @@ module Risc
 
       # initialize the dependency graph for instructions
       #
-      # starting from the given instruction, create InstructionPositions
+      # starting from the given instruction, create ObjectPositions
-      # for it and the whole chain
+      # for it and the whole chain. Then attach InstructionListeners
+      # for dependency tracking. All positions are initialized with -1
+      # and so setting the first will trigger a chain reaction
       #
-      # Set the next created to be dependent on the previous
+      # return the position for the first instruction which may be used to
-      def self.init( instruction , code)
+      # set all positions in the chain
+      def self.init( instruction , code )
+        first = nil
         while(instruction)
-          position = InstructionPosition.new(instruction , code)
+          position = ObjectPosition.new(instruction , -1)
+          first = position unless first
           nekst = instruction.next
           if nekst
-            listener = InstructionListener.new( nekst )
+            listener = InstructionListener.new( nekst , code )
             position.register_event(:position_changed , listener)
           end
           instruction = nekst
         end
-        position
+        first
       end
     end
   end

lib/risc/position/object_position.rb

@@ -12,10 +12,17 @@ module Risc
       # Give an integer as the actual position, where -1
       # which means no legal position known
       def initialize(object , pos )
-        @at = 0
+        @at = pos
         @object = object
+        Position.set_to(self , pos)
       end
 
+      #look for InstructionListener and return its code if found
+      def get_code
+        listener = event_table.find{|one| one.class == InstructionListener}
+        return nil unless listener
+        listener.code
+      end
       def +(offset)
         offset = offset.at if offset.is_a?(ObjectPosition)
         @at + offset

lib/risc/position/position.rb

@@ -57,7 +57,7 @@ module Risc
     end
 
     def self.set_to( position , to)
-      postest = Position.positions[position.object]
+      postest = Position.positions[position.object] unless to < 0 
       raise "Mismatch #{position}" if postest and postest != position
       @reverse_cache.delete(position.at) unless position.object.is_a? Label
       testing = self.at( position.at ) if position.at >= 0
@@ -73,5 +73,5 @@ module Risc
 end
 require_relative "object_position"
 require_relative "object_listener"
-require_relative "instruction_position"
+require_relative "instruction_listener"
 require_relative "code_listener"

test/risc/position/test_instruction_listener.rb

@@ -3,7 +3,7 @@ require_relative "helper"
 module Risc
   module Position
     # tests that require a boot and test propagation
-    class TestInstructionPosition < MiniTest::Test
+    class TestInstructionListener < MiniTest::Test
       def setup
         Risc.machine.boot
         @binary = Parfait::BinaryCode.new(1)
@@ -11,7 +11,7 @@ module Risc
         @label = Risc.label("hi","ho")
       end
       def test_init
-        assert InstructionPosition.init(@label , nil)
+        assert InstructionListener.init(@label , @binary)
       end
       def pest_set_instr
         pos = Position.set( @label , 8 , @binary)

test/risc/position/test_object_position.rb

@@ -3,7 +3,7 @@ require_relative "helper"
 module Risc
   module Position
     # tests that do no require a boot and only test basic positioning
-    class TestPositionBasic < MiniTest::Test
+    class TestObjectPosition < MiniTest::Test
 
       def test_init
         assert ObjectPosition.init(self , -1)
@@ -13,6 +13,9 @@ module Risc
         position = ObjectPosition.new(mov , 0)
         assert_equal 4, position.next_slot
       end
+      def test_has_get_code
+        assert_nil ObjectPosition.init(self , -1).get_code
+      end
       def pest_creation_ok
         assert ObjectPosition.new(self,0)
       end