diff --git a/lib/arm/compare_instruction.rb b/lib/arm/compare_instruction.rb
index da966350..ea805303 100644
--- a/lib/arm/compare_instruction.rb
+++ b/lib/arm/compare_instruction.rb
@@ -29,7 +29,7 @@ module Arm
         arg = Register::RegisterReference.new( arg )
       end
       if (arg.is_a?(Virtual::IntegerConstant))
-        if (arg.integer.fits_u8?)
+        if (arg.fits_u8?)
           # no shifting needed
           operand = arg.integer
           immediate = 1
diff --git a/lib/arm/constants.rb b/lib/arm/constants.rb
index ec4a7eb3..e0102bed 100644
--- a/lib/arm/constants.rb
+++ b/lib/arm/constants.rb
@@ -78,7 +78,7 @@ module Arm
      else
        u8_imm = parts[1].to_i(2)
      end
-     if (u8_imm.fits_u8?)
+     if (Virtual::IntegerConstant.new(u8_imm).fits_u8?)
        # can do!
        rot_imm = (pre_zeros+imm_len) / 2
        if (rot_imm > 15)
diff --git a/lib/arm/logic_instruction.rb b/lib/arm/logic_instruction.rb
index 0ffab048..f4e3c903 100644
--- a/lib/arm/logic_instruction.rb
+++ b/lib/arm/logic_instruction.rb
@@ -31,7 +31,7 @@ module Arm
         right = Virtual::IntegerConstant.new( right )
       end
       if (right.is_a?(Virtual::IntegerConstant))
-        if true #TODO (right.integer.fits_u8?)
+        if true #TODO (right.fits_u8?)
           # no shifting needed
           operand = right.integer
           immediate = 1
diff --git a/lib/arm/move_instruction.rb b/lib/arm/move_instruction.rb
index beb5e178..023f407c 100644
--- a/lib/arm/move_instruction.rb
+++ b/lib/arm/move_instruction.rb
@@ -35,7 +35,7 @@ module Arm
         right = Virtual::IntegerConstant.new( r_pos - self.position - 8 )
       end
       if (right.is_a?(Virtual::IntegerConstant))
-        if (right.integer.fits_u8?)
+        if (right.fits_u8?)
           return true
         elsif (calculate_u8_with_rr(right))
           return true
@@ -63,7 +63,7 @@ module Arm
         rn = :pc
       end
       if (right.is_a?(Virtual::IntegerConstant))
-        if (right.integer.fits_u8?)
+        if (right.fits_u8?)
           # no shifting needed
           operand = right.integer
           immediate = 1
@@ -75,7 +75,7 @@ module Arm
           operand = right.integer / 256
           immediate = 1
           
-#          raise "cannot fit numeric literal argument in operand #{right.inspect}"
+          raise "cannot fit numeric literal argument in operand #{right.inspect}"
         end
       elsif (right.is_a?(Symbol) or right.is_a?(Virtual::Integer))
         operand = reg_code(right)    #integer means the register the integer is in (otherwise constant)
diff --git a/lib/stream_reader.rb b/lib/stream_reader.rb
index 45598c87..ed88b079 100644
--- a/lib/stream_reader.rb
+++ b/lib/stream_reader.rb
@@ -1,9 +1,3 @@
-class Numeric
-  def fits_u8?
-    self >= 0 and self <= 255
-  end
-end
-
 module StreamReader
   def read_binary(size, count, type)
     d = __sr_read(size*count)
diff --git a/lib/virtual/constants.rb b/lib/virtual/constants.rb
index 63987b75..892f4f76 100644
--- a/lib/virtual/constants.rb
+++ b/lib/virtual/constants.rb
@@ -28,6 +28,9 @@ module Virtual
     def type
       Virtual::Integer
     end
+    def fits_u8?
+      integer >= 0 and integer <= 255
+    end
   end
 
   # The name really says it all.