Add more description to the reorder transpose functions.

libraries/base/reorder/src/vhdl/reorder_pkg.vhd

@@ -78,6 +78,17 @@ package reorder_pkg is
 
   -----------------------------------------------------------------------------
   -- Reorder transpose
+  --
+  -- There are several functions that yield the same transpose, but for
+  -- different purposes.
+  -- . func_reorder_transpose_indices() and
+  --   func_reorder_transpose_indices_impl() calculate a lookup table of all
+  --   indices in advance using loops.
+  -- . func_reorder_transpose_packet() applies func_reorder_transpose_indices()
+  --   on a packet list of octet values, for in a test bench.
+  -- . func_reorder_transpose() and func_reorder_transpose_look_up()
+  --   sequentially calculate the next index per clock cycle and use
+  --   t_reorder_transpose, for in a synthesis component.
   -----------------------------------------------------------------------------
 
   -- Block and data counters to derive select_copi.address for transpose