fix padding

used to be that type and layout were hidden
now type is gone and layout is an explicit instance, so 0 overhead

lib/register/padding.rb

@@ -2,10 +2,8 @@
 module Padding
 
   # objects only come in lengths of multiple of 8 words
-  # but there is a constant overhead of 1 words for layout
-  # and as we would have to subtract 1 to make it work without overhead, we now have to add 7
   def padded len
-    a = 32 * (1 + (len + 3)/32 )
+    a = 32 * (1 + (len - 1)/32 )
     #puts "#{a} for #{len}"
     a
   end
@@ -15,7 +13,7 @@ module Padding
   end
 
   def padding_for length
-    pad = padded(length) - length - 4 # for header, layout
+    pad = padded(length) - length  # for header, layout
     pad
   end
 end

test/register/test_padding.rb

@@ -10,17 +10,17 @@ class TestPadding < MiniTest::Test
     @pad = Padded.new
   end
   def test_small
-    [6,20,27,28].each do |p|
+    [6,27,28,32].each do |p|
       assert_equal 32 , @pad.padded(p) , "Expecting 32 for #{p}"
     end
   end
   def test_medium
-    [29,40,57,60].each do |p|
+    [33,40,57,60,64].each do |p|
       assert_equal 64 , @pad.padded(p) , "Expecting 64 for #{p}"
     end
   end
   def test_large
-    [61,88].each do |p|
+    [65,88].each do |p|
       assert_equal 96 , @pad.padded(p) , "Expecting 96 for #{p}"
     end
   end