From 90d3ed291a7d83f2cf1363ee2abf582743e5b609 Mon Sep 17 00:00:00 2001 From: lkcl Date: Wed, 4 Aug 2021 02:21:43 +0100 Subject: [PATCH] --- openpower/sv/setvl.mdwn | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/openpower/sv/setvl.mdwn b/openpower/sv/setvl.mdwn index b4024b4ac..11b3cbd46 100644 --- a/openpower/sv/setvl.mdwn +++ b/openpower/sv/setvl.mdwn @@ -111,6 +111,26 @@ the same instruction. That would require two instructions. # setmvlhi +In Vertical-First Mode the minimum expectation is that one scalar +element may be executed by each instruction. There are however +circumstances where it may be possible to execute more than one: +determining a "safe minimum amount" may not be practical. + +Therefore, setmvlhi may specify, as determined by the compiler, +exactly what that quantity is. Unlike VL, which is an amount +that, when requested, **must** be executed, VFhint may be set +to an amount that the hardware is capable of. + +Critical to note are two things: + +1. VFhint must not be set by hardware to an amount that +exceeds either MVL or the requested amount, and must set +VFhint to at least 1 element. +2. svstep will increment srcstep and dststep by VFhint, +therefore when hardware says it can perform N element +operations, hardware **MUST** perform N operations +for every single instruction. + Form: SVL-Form (see [[isatables/fields.text]]) | 0.5|6.10|11.15|16..21|22 | 23...25 | 26.30 |31| name | -- 2.30.2