diff --git a/lib/arm/machine_code.rb b/lib/arm/machine_code.rb
index 0c5c6d45..764772f8 100644
--- a/lib/arm/machine_code.rb
+++ b/lib/arm/machine_code.rb
@@ -44,7 +44,7 @@ module Arm
     end
 
 
-    # the number (a Risc::integer) is (itself) divided by 10, ie overwritten by the result
+    # the number (a Risc::Integer) is (itself) divided by 10, ie overwritten by the result
     #  and the remainder is overwritten (ie an out argument)
     # not really a function, more a macro,
     def div10( function, number , remainder )
diff --git a/lib/mom/instruction/dynamic_call.rb b/lib/mom/instruction/dynamic_call.rb
index 827045cf..680981fe 100644
--- a/lib/mom/instruction/dynamic_call.rb
+++ b/lib/mom/instruction/dynamic_call.rb
@@ -25,7 +25,7 @@ module Mom
     # Instead we need a DynamicJump instruction that explicitly takes a register as
     # a target (not a label)
     def to_risc(compiler)
-      reg = compiler.use_reg( :int )
+      reg = compiler.use_reg( :Object )
       call =  Risc.load_constant( self , @cache_entry , reg )
       method_index = Risc.resolve_to_index(:cache_entry , :cached_method)
       call << Risc::SlotToReg.new( self , reg ,method_index, reg)
diff --git a/lib/mom/instruction/return_sequence.rb b/lib/mom/instruction/return_sequence.rb
index 248c433e..ddf358b0 100644
--- a/lib/mom/instruction/return_sequence.rb
+++ b/lib/mom/instruction/return_sequence.rb
@@ -22,7 +22,7 @@ module Mom
     def to_risc(compiler)
       return_move = SlotLoad.new( [:message , :caller,:return_value] , [:message , :return_value],self)
       moves = return_move.to_risc(compiler)
-      return_address = compiler.use_reg(:int)
+      return_address = compiler.use_reg(:Object)
       compiler.reset_regs
       caller_index = Risc.resolve_to_index(:message , :caller)
       return_index = Risc.resolve_to_index(:message , :return_address)
diff --git a/lib/mom/instruction/simple_call.rb b/lib/mom/instruction/simple_call.rb
index c2fa339c..29c79279 100644
--- a/lib/mom/instruction/simple_call.rb
+++ b/lib/mom/instruction/simple_call.rb
@@ -20,7 +20,7 @@ module Mom
     # For returning, we add a label after the call, and load it's address into the
     # return_address of the next_message, for the ReturnSequence to pick it up.
     def to_risc(compiler)
-      jump_address = compiler.use_reg(:int)
+      jump_address = compiler.use_reg(:Object)
       return_label = Risc::Label.new(self,"continue_#{object_id}")
       save_return =  SlotLoad.new([:message,:next_message,:return_address],[return_label],self)
       moves = save_return.to_risc(compiler)
diff --git a/lib/mom/instruction/slot_load.rb b/lib/mom/instruction/slot_load.rb
index 5ae24710..44c3d3e6 100644
--- a/lib/mom/instruction/slot_load.rb
+++ b/lib/mom/instruction/slot_load.rb
@@ -43,13 +43,13 @@ module Mom
         left_index = Risc.resolve_to_index(@left.known_object , left_slots.first)
         if left_slots.length > 1
           # swap the existing target (with a new reg) and update the index
-          new_left = compiler.use_reg( :int )
+          new_left = compiler.use_reg( :Object )
           const << Risc::SlotToReg.new( original_source , left ,left_index, new_left)
           left = new_left
           left_index = SlotLoad.resolve_to_index(left_slots[0] , left_slots[1] ,compiler)
           if left_slots.length > 2
             #same again, once more updating target
-            new_left = compiler.use_reg( :int )
+            new_left = compiler.use_reg( :Object )
             const << Risc::SlotToReg.new( original_source , left ,left_index, new_left)
             left = new_left
             left_index = SlotLoad.resolve_to_index(left_slots[1] , left_slots[2] ,compiler)
@@ -57,7 +57,7 @@ module Mom
           raise "more slots not implemented #{left_slots}" if left_slots.length > 3
         end
       when Parfait::CacheEntry
-        left = compiler.use_reg( :int )
+        left = compiler.use_reg( :Object )
         const << Risc.load_constant(original_source, @left.known_object , left)
         left_index = Risc.resolve_to_index(:cache_entry , left_slots.first)
       else
@@ -105,7 +105,7 @@ module Mom
     end
 
     def to_register(compiler, instruction)
-      type = known_object.respond_to?(:ct_type) ? known_object.ct_type : :int
+      type = known_object.respond_to?(:ct_type) ? known_object.ct_type : :Object
       right = compiler.use_reg( type )
       case known_object
       when Constant
diff --git a/lib/risc/builtin/integer.rb b/lib/risc/builtin/integer.rb
index 2b9d874a..20d28366 100644
--- a/lib/risc/builtin/integer.rb
+++ b/lib/risc/builtin/integer.rb
@@ -17,7 +17,7 @@ module Risc
 
         def +( context )
           source = "plus"
-          compiler = compiler_for(:Integer,:+ ,{other: :int})
+          compiler = compiler_for(:Integer,:+ ,{other: :Integer})
           me , other = self_and_int_arg(compiler,source + "1")
           # reduce me and other to integers
           compiler.add_slot_to_reg( source + "2" , me , 2 , me)