From 9a4dec12f0d7f5d47291925094f5dcb187fb965a Mon Sep 17 00:00:00 2001 From: Jacob Lifshay Date: Wed, 12 Apr 2023 13:37:47 -0700 Subject: [PATCH] shift-add is useful even with LD-ST-indexed-shifted --- openpower/sv/rfc/ls004.mdwn | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/openpower/sv/rfc/ls004.mdwn b/openpower/sv/rfc/ls004.mdwn index fe8c1513e..24c35769e 100644 --- a/openpower/sv/rfc/ls004.mdwn +++ b/openpower/sv/rfc/ls004.mdwn @@ -73,6 +73,10 @@ add shift-and-add. Replaces a pair of explicit instructions in hot-loops. as the second operand is constrained to lower 32-bits and zero-extended. 3. Both are 2-in 1-out instructions. +4. shift-add operations are present in both x86 and aarch64, + since they are useful for both general arithmetic and for + computing addresses even when not immediately followed + with a load/store. TODO: signed 32-bit shift-and-add should be added, this needs to be addressed before submitting the RFC: -- 2.30.2