From: Luke Kenneth Casson Leighton <lkcl@lkcl.net>
Date: Sun, 13 Mar 2022 13:43:02 +0000 (+0000)
Subject: add new grev diagram
X-Git-Tag: opf_rfc_ls005_v1~3075
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=5a27e857cdf16b2c55d81ecd320ee700caa25831;p=libreriscv.git

add new grev diagram
---

diff --git a/openpower/sv/bitmanip.mdwn b/openpower/sv/bitmanip.mdwn
index 208f642b5..ad576763b 100644
--- a/openpower/sv/bitmanip.mdwn
+++ b/openpower/sv/bitmanip.mdwn
@@ -337,11 +337,15 @@ the two LUT2s are applied left-half (when not swapping)
 and right-half (when swapping) so as to allow a wider
 range of options
 
+<img src="/openpower/sv/grevlut2x2.jpg" width=700 />
+
 grevlut should be arranged so as to produce the constants
 needed to put into bext (bitextract) so as in turn to
 be able to emulate x86 pmovmask instructions <https://www.felixcloutier.com/x86/pmovmskb>
 
-<img src="/openpower/sv/grevlut2x2.jpg" width=700 />
+Better diagram showing the correct ordering of shamt.
+
+<img src="/openpower/sv/grevlut.png" width=700 />
 
 ```
 lut2(imm, a, b):