From c2d7c70fe39fbd6e3aa4b1020f20173245e3bbf4 Mon Sep 17 00:00:00 2001 From: lkcl Date: Sat, 14 May 2022 22:27:55 +0100 Subject: [PATCH] --- openpower/sv/SimpleV_rationale.mdwn | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/openpower/sv/SimpleV_rationale.mdwn b/openpower/sv/SimpleV_rationale.mdwn index ea0a6e8ed..ddf787c51 100644 --- a/openpower/sv/SimpleV_rationale.mdwn +++ b/openpower/sv/SimpleV_rationale.mdwn @@ -956,10 +956,11 @@ The reason in this case for the use of Vertical-First Mode is the conditional execution of the Multiply-and-Accumulate. Horizontal-First Mode is the standard Cray-Style Vectorisation: loop on all *elements* with the same instruction before moving -on to the next instruction. Predication needs to be pre-calculated +on to the next instruction. Horizontal-First +Predication needs to be pre-calculated for the entire Vector in order to exclude certain elements from the computation. In this case, that's an expensive inconvenience -(similar to the problems associated with Memory-to-Memory +(remarkably similar to the problems associated with Memory-to-Memory Vector Machines such as the CDC Star-100). Vertical-First allows *scalar* instructions and -- 2.30.2