From 5268a5c602d288d3dc2d819ee1faad365a221093 Mon Sep 17 00:00:00 2001 From: Luke Kenneth Casson Leighton Date: Wed, 27 Jul 2022 02:27:00 +0100 Subject: [PATCH] ARM NEON is PackedSIMD --- openpower/sv/executive_summary.mdwn | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/openpower/sv/executive_summary.mdwn b/openpower/sv/executive_summary.mdwn index 48fabfc5c..aa9039a51 100644 --- a/openpower/sv/executive_summary.mdwn +++ b/openpower/sv/executive_summary.mdwn @@ -50,10 +50,11 @@ the provision of a `setvl` instruction, and why they are each called "Scalable" Vectors, because it is the `setvl` instruction that presents the **programmer** with explicit control over Vector length. -ARM NEON, AVX-512 and ARM SVE2 are all Predicated SIMD ISAs and -**do not provide Scalability to the Programmer**. SVE2 is **Silicon** +VSX and NEON are PackedSIMD, and +AVX-512 and ARM SVE2 are Predicated SIMD ISAs. +**None of them provide Scalability to the Programmer**. SVE2 is **Silicon** Scalable, not **Programmer** Scalable: the distinction is profoundly -important. +important (already causing problems). For Predicated SIMD, Programmers must emulate Cray-style scaling through explicit predicate masking, which increases instruction count in hot-loops. -- 2.30.2