clarify docstring on id_regs.py

diff --git a/id_regs.py b/id_regs.py
index d74f088dfd83ae750d9814187751f771caca634a..cc1596ab8e22f37b7c3a009ab9c54a5fcc6f93f3 100644 (file)
--- a/id_regs.py
+++ b/id_regs.py
@@ -11,6 +11,11 @@
     however there may be circumstances where the behaviour of an
     instruction has to change depending on "tags" associated with
     the registers (security extensions, simple-v extension).
+
+    therefore this code walks the instruction implementations
+    in riscv/insns/*.h looking for register usage patterns.
+    the resultant table can be used *prior* to the emulation,
+    without having to manually maintain such a table.
 """
 
 import os