From: Luke Kenneth Casson Leighton <lkcl@lkcl.net>
Date: Sun, 18 Sep 2022 16:33:32 +0000 (+0100)
Subject: reverse decode_bo inv/eq/lt/le/etc. thing
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=361df8c7c74f3e58ef71c0b436fcce7b7aeb1ee9;p=openpower-isa.git

reverse decode_bo inv/eq/lt/le/etc. thing
rather than piss about modifying the table itself, do an MSB0-LSB0 swap
---

diff --git a/src/openpower/sv/trans/svp64.py b/src/openpower/sv/trans/svp64.py
index 40fdc0ef..36bd3bfe 100644
--- a/src/openpower/sv/trans/svp64.py
+++ b/src/openpower/sv/trans/svp64.py
@@ -645,7 +645,9 @@ def decode_bo(encoding):
     }
     assert encoding in pmap, \
         "encoding %s for BO Mode not recognised" % encoding
-    return pmap[encoding]
+    # barse-ackwards MSB0/LSB0. sigh
+    mapped = pmap[encoding]
+    return int(bin(mapped)[:1:-1], 2) # to 0bNNN, reverse-and-strip b0, base2
 
 
 # partial-decode fail-first mode