add explanatory README.txt

diff --git a/openpower/README.txt b/openpower/README.txt
new file mode 100644 (file)
index 0000000..518db9c
--- /dev/null
+++ b/openpower/README.txt
@@ -0,0 +1,10 @@
+The files in this directory have come from many locations
+
+* isatables CSV files are from Microwatt decode1.vhdl which is
+  CC 4.0 Copyrighted
+* isatables fields.txt is from the OpenPOWER v3.0B specification which
+  is managed by the OpenPOWER Foundation
+* isa markdown files are extracted from the OpenPOWER v3.0B specification which
+  is managed by the OpenPOWER Foundation
+* python files are written by Libre-SOC team members and are LGPLv3+ licensed
+