From: lkcl <lkcl@web>
Date: Thu, 18 Aug 2022 23:43:37 +0000 (+0100)
Subject: (no commit message)
X-Git-Tag: opf_rfc_ls005_v1~837
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=ae672834f8bff2378668e3f5673b043ebbaf79c4;p=libreriscv.git

---

diff --git a/openpower/sv/remap.mdwn b/openpower/sv/remap.mdwn
index 485a27046..45e5f9c44 100644
--- a/openpower/sv/remap.mdwn
+++ b/openpower/sv/remap.mdwn
@@ -229,12 +229,18 @@ all *already* critically depend on overlapping Reads/Writes: Matrix
 uses overlapping registers as accumulators.  Thus the Register Hazard
 Management needed by Indexed REMAP *has* to be in place anyway.
 
+The cost compared to Matrix and other REMAPs (and Pack/Unpack) is
+clearly that of the additional reading of the GPRs to be used as Indices,
+plus the setup cost associated with creating those same Infices.
+If any Deterministic REMAP can cover the required task, clearly it
+is adviseable to use it instead.
+
 *Programmer's note: some algorithms may require skipping of Indices exceeding
 VL-1, not MAXVL-1. This may be achieved programmatically by performing
-a `sv.cmp *RA,RB` where RA is the same GPRs used in the Indexed REMAP,
+an `sv.cmp *BF,*RA,RB` where RA is the same GPRs used in the Indexed REMAP,
 and RB contains the value of VL returned from `setvl`. The resultant
 CR Fields may then be used as Predicate Masks to exclude those operations
-with an Index exceeding VL-1*
+with an Index exceeding VL-1.*
 
 # REMAP area of SVSTATE