From 0912656f1789cc741450e0385f8420f8f727d51c Mon Sep 17 00:00:00 2001 From: Jacob Lifshay Date: Thu, 2 Mar 2023 21:41:01 -0800 Subject: [PATCH] add justification for maddedus --- openpower/sv/rfc/ls003.mdwn | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/openpower/sv/rfc/ls003.mdwn b/openpower/sv/rfc/ls003.mdwn index 3d7615a9e..2e231eafa 100644 --- a/openpower/sv/rfc/ls003.mdwn +++ b/openpower/sv/rfc/ls003.mdwn @@ -91,6 +91,11 @@ TODO: address Jacob's comments: https://libre-soc.org/irclog/%23libre-soc.2022-1 6. These are all 3-in 2-out instructions. If Power ISA did not already have LD/ST-with-update instructions and instructions with `RAp` and `RTp` then these instructions would not be proposed. +7. `maddedus` is the first scalar signed/unsigned multiply instruction, the + only other signed/unsigned multiply instruction is `vmsummbm`, which has the + drawbacks that it is rather specialist, only working on bytes, + requires VSX/VMX, and isn't very suited for big-integer multiplication or + other general integer arithmetic. **Changes** -- 2.30.2