more work on instrucitons, mov this time

lib/arm/constants.rb

@@ -83,5 +83,27 @@ module Arm
        return nil
      end
    end
+   
+   #slighly wrong place for this code, but since the module gets included in instructions anyway . . .
+   # implement the barrel shifter on the operand (which is set up before as an integer)
+   def shift_handling
+     #codes that one can shift, first two probably most common.
+     # l (in lsr) means logical, ie unsigned, a (in asr) is arithmetic, ie signed
+     {'lsl' => 0b000, 'lsr' => 0b010, 'asr' => 0b100, 'ror' => 0b110, 'rrx' => 0b110}.each do |short, bin|
+       long = "shift_#{short}".to_sym
+       if shif = @attributes[long]
+         shif = shif.integer if (shif.is_a?(Vm::IntegerConstant))
+         if (shif.is_a?(Vm::Integer))
+           raise "should not be supported, check code #{inspect}"
+           bin |= 0x1;
+           shift = shif.register << 1
+         end
+         raise "0 < shift <= 32  #{shif} #{inspect}"  if (shif >= 32) or( shif < 0)
+         @operand |=   shift(bin  , 4 )
+         @operand |=   shift(shif , 4+3)
+         break
+       end
+     end
+   end
   end
 end