From 52ede886a947132e4f4218f1fb6dc143c31cc44a Mon Sep 17 00:00:00 2001 From: Luke Kenneth Casson Leighton Date: Wed, 5 Apr 2023 10:57:38 +0100 Subject: [PATCH] programmers note about RC1 with DD-FF-LDST --- openpower/sv/ldst.mdwn | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/openpower/sv/ldst.mdwn b/openpower/sv/ldst.mdwn index 1623f513f..614dc6ed0 100644 --- a/openpower/sv/ldst.mdwn +++ b/openpower/sv/ldst.mdwn @@ -477,6 +477,10 @@ nodes. If VLi=1 it will load the NULL pointer into the Vector of results. If however VLi=0 it will *exclude* the NULL pointer by truncating VL to one Element earlier. +*Programmer's Note: by also setting the RC1 qualifier as well as setting +VLi=1 it is possible to establish a Predicate Mask such that the first +zero in the predicate will be the NULL pointer* + ``` RT=1 # vec - deliberately overlaps by one with RA RA=0 # vec - first one is valid, contains ptr -- 2.30.2