diff --git a/lib/mom/instruction/simple_call.rb b/lib/mom/instruction/simple_call.rb
index e3f9b5c3..b6a517ee 100644
--- a/lib/mom/instruction/simple_call.rb
+++ b/lib/mom/instruction/simple_call.rb
@@ -23,14 +23,16 @@ 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)
+      method = @method
       return_label = Risc.label(self,"continue_#{object_id}")
-      save_return =  SlotLoad.new([:message,:next_message,:return_address],[return_label],self)
-      moves = save_return.to_risc(compiler)
-      moves << Risc.slot_to_reg(self, Risc.message_reg , :next_message , Risc.message_reg)
-
-      moves << Risc::FunctionCall.new(self, method )
-
-      moves << return_label
+      compiler.build("SimpleCall") do
+        return_address! << return_label
+        next_message! << message[:next_message]
+        next_message[:return_address] << return_address
+        message << message[:next_message]
+        add_code Risc::FunctionCall.new("SimpleCall", method )
+        add_code return_label
+      end
     end
 
   end
diff --git a/lib/mom/instruction/truth_check.rb b/lib/mom/instruction/truth_check.rb
index 0e8bcbd3..8f5af60d 100644
--- a/lib/mom/instruction/truth_check.rb
+++ b/lib/mom/instruction/truth_check.rb
@@ -20,17 +20,18 @@ module Mom
 
     def to_risc(compiler)
       false_label = @false_jump.to_risc(compiler)
-      left = @condition.to_register(compiler,self)
-      false_load = SlotDefinition.new( FalseConstant.new , [] ).to_register(compiler,self)
-      left << false_load
-      left << Risc.op( self , :- , left.register , false_load.register)
-      left << Risc::IsZero.new( self, false_label)
-      nil_load = SlotDefinition.new( NilConstant.new , [] ).to_register(compiler,self)
-      left << nil_load
-      left << Risc.op( self , :- , left.register , nil_load.register)
-      left << Risc::IsZero.new( self, false_label)
-
-      left
+      builder = compiler.code_builder("TruthCheck")
+      condition_code = @condition.to_register(compiler,self)
+      condition = condition_code.register#.set_builder(builder)
+      built = builder.build do
+        object! << Parfait.object_space.false_object
+        object.op :- , condition
+        if_zero false_label
+        object << Parfait.object_space.nil_object
+        object.op :- , condition
+        if_zero false_label
+      end
+      condition_code << built
     end
 
   end