From 9af95c88a1364fafc906f48164a536dd2af6c9dc Mon Sep 17 00:00:00 2001 From: Hugues de Lassus Date: Tue, 18 Apr 2023 12:16:05 -0700 Subject: [PATCH] Clarify how the largest element index is determined Fixes #873 Signed-off-by: Hugues de Lassus --- v-spec.adoc | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/v-spec.adoc b/v-spec.adoc index ab621a7..541c2d8 100644 --- a/v-spec.adoc +++ b/v-spec.adoc @@ -558,8 +558,9 @@ setting (8) and the smallest SEW setting (8), so VLMAX_max = 8*VLEN/8 = VLEN. For example, for VLEN=256, `vstart` would have 8 bits to represent indices from 0 through 255. -The use of `vstart` values greater than the largest element index for -the current `vtype` setting is reserved. +The use of `vstart` values greater than the largest element index is reserved. +The largest element index is determined using the effective element width and +effective group multiplier of the current instruction. NOTE: It is recommended that implementations trap if `vstart` is out of bounds. It is not required to trap, as a possible future use of