fix slot_load for higher order left arguments

needed for getting args or frame of the target, for assigns
fixed ripples in tests

test/mom/test_assign_arg_const.rb

@@ -7,7 +7,7 @@ module Risc
     def setup
       super
       @input = "arg = 5"
-      @expect = [LoadConstant, RegToSlot]
+      @expect = [LoadConstant, SlotToReg, RegToSlot]
     end
     def test_local_assign_instructions
       assert_nil msg = check_nil , msg
@@ -20,7 +20,12 @@ module Risc
 
     def test_slot_move
       produced = produce_body
-      assert_equal produced.next.register , produced.register
+      assert_equal produced.next(2).register , produced.register
+    end
+    def test_load_args_from_message
+      produced = produce_body
+      assert_equal :r0 , produced.next.array.symbol , produced.next.to_rxf
+      assert_equal 9 , produced.next.index , produced.next.to_rxf
     end
 
   end

test/mom/test_assign_ivar_const.rb

@@ -7,7 +7,7 @@ module Risc
     def setup
       super
       @input = "@ivar = 5"
-      @expect = [LoadConstant, RegToSlot]
+      @expect = [LoadConstant, SlotToReg, RegToSlot]
     end
     def test_local_assign_instructions
       assert_nil msg = check_nil , msg
@@ -20,7 +20,13 @@ module Risc
 
     def test_slot_move
       produced = produce_body
-      assert_equal produced.next.register , produced.register
+      assert_equal produced.next.next.register , produced.register
+    end
+
+    def test_load_self_from_message
+      produced = produce_body
+      assert_equal :r0 , produced.next.array.symbol , produced.next.to_rxf
+      assert_equal 3 , produced.next.index , produced.next.to_rxf
     end
 
   end

test/mom/test_assign_local_arg.rb

@@ -7,7 +7,7 @@ module Risc
     def setup
       super
       @input = "local = arg"
-      @expect = [SlotToReg, SlotToReg, RegToSlot]
+      @expect = [SlotToReg, SlotToReg, SlotToReg, RegToSlot]
     end
     def test_local_assign_instructions
       assert_nil msg = check_nil , msg
@@ -15,8 +15,17 @@ module Risc
 
     def test_slot_move
       produced = produce_body
-      assert_equal produced.next.next.register , produced.register
+      assert_equal produced.next(3).register , produced.register
+    end
+    def test_load_args_from_message
+      produced = produce_body
+      assert_equal :r0 , produced.array.symbol , produced.next.to_rxf
+      assert_equal 9 , produced.index , produced.next.to_rxf
+    end
+    def test_load_frame_from_message
+      produced = produce_body
+      assert_equal :r0 , produced.next(2).array.symbol , produced.next.to_rxf
+      assert_equal 2 , produced.next.index , produced.next.to_rxf
     end
-
   end
 end

test/mom/test_assign_local_const.rb

@@ -7,7 +7,7 @@ module Risc
     def setup
       super
       @input = "r = 5"
-      @expect = [LoadConstant, RegToSlot]
+      @expect = [LoadConstant,SlotToReg, RegToSlot]
     end
     def test_local_assign_instructions
       assert_nil msg = check_nil , msg
@@ -20,7 +20,7 @@ module Risc
 
     def test_slot_move
       produced = produce_body
-      assert_equal produced.next.register , produced.register
+      assert_equal produced.next(2).register , produced.register
     end
 
   end

test/mom/test_assign_local_ivar.rb

@@ -7,7 +7,8 @@ module Risc
     def setup
       super
       @input = "@ivar = 5 ; r = @ivar"
-      @expect = [LoadConstant, RegToSlot, SlotToReg, SlotToReg, RegToSlot]
+      @expect = [LoadConstant, SlotToReg, RegToSlot, SlotToReg, SlotToReg, SlotToReg ,
+                 RegToSlot]
     end
     def test_local_assign_instructions
       assert_nil msg = check_nil , msg
@@ -20,7 +21,7 @@ module Risc
 
     def test_slot_move
       produced = produce_body
-      assert_equal produced.next.register , produced.register
+      assert_equal produced.next(2).register , produced.register
     end
 
   end

test/mom/test_assign_local_send.rb

@@ -7,8 +7,8 @@ module Risc
     def setup
       super
       @input = "r = 5.mod4"
-      @expect = [Label, LoadConstant, RegToSlot, Label, Label, SlotToReg ,
-                 RegToSlot]
+      @expect = [Label, LoadConstant, SlotToReg, RegToSlot, Label, Label ,
+                 SlotToReg, SlotToReg, RegToSlot]
     end
     def test_local_assign_instructions
       assert_nil msg = check_nil , msg