diff --git a/lib/arm/logic_instruction.rb b/lib/arm/logic_instruction.rb
index 1718986f..902b54b2 100644
--- a/lib/arm/logic_instruction.rb
+++ b/lib/arm/logic_instruction.rb
@@ -11,29 +11,25 @@ module Arm
       @attributes[:condition_code] = :al if @attributes[:condition_code] == nil
       @operand = 0
 
-      @rn = nil
+      @left = nil
       @i = 0      
     end
-    attr_accessor :i, :rn
     
-    # Build representation for source value 
-    def build
-      @rn = @attributes[:right]
-      do_build @attributes[:extra]
-    end
-
     # arm intrucioons are pretty sensible, and always 4 bytes (thumb not supported)
     def length
       4
     end
 
-    #(stays in subclases, while build is overriden to provide different arguments)
-    def do_build(arg)      
+    # Build representation for source value 
+    def build
+      @left = @attributes[:left]
+      arg = @attributes[:extra]
+      
       if arg.is_a?(Vm::StringConstant)
         # do pc relative addressing with the difference to the instuction
         # 8 is for the funny pipeline adjustment (ie oc pointing to fetch and not execute)
         arg = Vm::IntegerConstant.new( arg.position - self.position - 8 )
-        @rn = :pc
+        @left = :pc
       end
       if( arg.is_a? Fixnum ) #HACK to not have to change the code just now
         arg = Vm::IntegerConstant.new( arg )
@@ -89,7 +85,7 @@ module Arm
       val = shift(val , 0)
       raise inspect unless reg_code(@first)
       val |= shift(reg_code(@first) ,            12)     
-      val |= shift(reg_code(@rn) ,            12+4)   
+      val |= shift(reg_code(@left) ,            12+4)   
       val |= shift(@attributes[:update_status_flag] , 12+4+4)#20 
       val |= shift(op_bit_code ,        12+4+4  +1)
       val |= shift(@i ,                  12+4+4  +1+4) 
diff --git a/test/test_arm.rb b/test/test_arm.rb
index 057210a9..40798cc6 100644
--- a/test/test_arm.rb
+++ b/test/test_arm.rb
@@ -27,15 +27,15 @@ class TestArmAsm < MiniTest::Test
     end
   end
   def test_adc
-    code = @machine.adc	 :r1, right: :r3, :extra => :r5
+    code = @machine.adc	 :r1, left: :r3, :extra => :r5
     assert_code code , :adc , [0x05,0x10,0xa3,0xe0] #e0 a3 10 05
   end
   def test_add
-    code = @machine.add	 :r1 , right: :r1, :extra => :r3
+    code = @machine.add	 :r1 , left: :r1, :extra => :r3
     assert_code code , :add , [0x03,0x10,0x81,0xe0] #e0 81 10 03
   end
   def test_and # inst eval doesn't really work with and
-    code = @machine.and(  :r1 , right: :r2 , :extra => :r3)
+    code = @machine.and(  :r1 , left: :r2 , :extra => :r3)
     assert_code code , :and , [0x03,0x10,0x02,0xe0] #e0 01 10 03
   end
   def test_b
@@ -50,7 +50,7 @@ class TestArmAsm < MiniTest::Test
     assert_code code , :call, [0xff,0xff,0xff,0xeb] #ea ff ff fe
   end
   def test_bic
-    code = @machine.bic	 :r2 , right: :r2 , :extra => :r3
+    code = @machine.bic	 :r2 , left: :r2 , :extra => :r3
     assert_code code , :bic , [0x03,0x20,0xc2,0xe1] #e3 c2 20 44
   end
   def test_cmn
@@ -62,7 +62,7 @@ class TestArmAsm < MiniTest::Test
     assert_code code , :cmp , [0x02,0x00,0x51,0xe1] #e1 51 00 02
   end
   def test_eor
-    code = @machine.eor	 :r2 , right: :r2 , :extra => :r3
+    code = @machine.eor	 :r2 , left: :r2 , :extra => :r3
     assert_code code , :eor , [0x03,0x20,0x22,0xe0] #e0 22 20 03
   end
   def test_ldr
@@ -78,7 +78,7 @@ class TestArmAsm < MiniTest::Test
     assert_code code, :ldrb ,  [0x00,0x00,0xd0,0xe5] #e5 d0 00 00
   end
   def test_orr
-    code = @machine.orr	 :r2 , right: :r2 , :extra => :r3
+    code = @machine.orr	 :r2 , left: :r2 , :extra => :r3
     assert_code code , :orr , [0x03,0x20,0x82,0xe1] #e1 82 20 03
   end
   def test_push
@@ -90,15 +90,15 @@ class TestArmAsm < MiniTest::Test
     assert_code code , :pop , [0x00,0x80,0xbd,0xe8] #e8 bd 80 00
   end
   def test_rsb
-    code = @machine.rsb	 :r1 , right: :r2 , :extra => :r3
+    code = @machine.rsb	 :r1 , left: :r2 , :extra => :r3
     assert_code code , :rsb , [0x03,0x10,0x62,0xe0]#e0 62 10 03
   end
   def test_rsc
-    code = @machine.rsc	 :r2 , right: :r3 , :extra => :r4
+    code = @machine.rsc	 :r2 , left: :r3 , :extra => :r4
     assert_code code , :rsc , [0x04,0x20,0xe3,0xe0]#e0 e3 20 04
   end
   def test_sbc
-    code = @machine.sbc	 :r3, right: :r4 , :extra => :r5
+    code = @machine.sbc	 :r3, left: :r4 , :extra => :r5
     assert_code code , :sbc , [0x05,0x30,0xc4,0xe0]#e0 c4 30 05
   end
   def test_str
@@ -110,7 +110,7 @@ class TestArmAsm < MiniTest::Test
     assert_code code, :strb ,  [0x00,0x00,0xc0,0xe5] #e5 c0 00 00
   end
   def test_sub
-    code = @machine.sub  :r2, right: :r0, :extra => 1
+    code = @machine.sub  :r2, left: :r0, :extra => 1
     assert_code code, :sub ,  [0x01,0x20,0x40,0xe2] #e2 40 20 01 
   end
   def test_swi
diff --git a/test/test_small_program.rb b/test/test_small_program.rb
index 43781a9f..704c5f53 100644
--- a/test/test_small_program.rb
+++ b/test/test_small_program.rb
@@ -18,7 +18,7 @@ class TestSmallProg < MiniTest::Test
       start = Vm::Block.new("start")
       add_code start
       start.instance_eval do
-        sub  :r0, right: :r0, :extra => 1 , :update_status_flag => 1      #2
+        sub  :r0, left: :r0, :extra => 1 , :update_status_flag => 1      #2
         bne  start  ,{}         #3
       end
     end