add extra comment block explaining pipe stage example

diff --git a/src/add/example_buf_pipe.py b/src/add/example_buf_pipe.py
index 0f2c97462dc3a82fb39f5b4aba20ed02a341ea6b..8f3742259518750dd93f005276ac4bd1f19e672b 100644 (file)
--- a/src/add/example_buf_pipe.py
+++ b/src/add/example_buf_pipe.py
@@ -69,7 +69,17 @@ class ExampleStage:
 
     def __init__(self):
         """ i_data can be a DIFFERENT type from everything else
-            o_data, r_data and result must be of the same type
+            o_data, r_data and result are best of the same type.
+            however this is not strictly the case.  an intermediate
+            transformation process could hypothetically be applied, however
+            it is result and r_data that definitively need to be of the same
+            (intermediary) type, as it is both result and r_data that
+            are transferred into o_data:
+
+            i_data -> process() -> result --> o_data
+                                     |           ^
+                                     |           |
+                                     +-> r_data -+
         """
         self.i_data = Signal(16)
         self.r_data = Signal(16)