From: lkcl <lkcl@web>
Date: Sun, 26 Jun 2022 14:26:24 +0000 (+0100)
Subject: (no commit message)
X-Git-Tag: opf_rfc_ls005_v1~1515
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=8524cda6a12782d8819868c5929a166eea110fdd;p=libreriscv.git

---

diff --git a/openpower/sv/svp64/appendix.mdwn b/openpower/sv/svp64/appendix.mdwn
index fc15904a7..365d8a8f5 100644
--- a/openpower/sv/svp64/appendix.mdwn
+++ b/openpower/sv/svp64/appendix.mdwn
@@ -604,7 +604,7 @@ will **not** be overwritten and will **not** be zero'd.
 
 Note that when SVM is clear and SUBVL!=1 the sub-elements are
 *independent*, i.e. they are mapreduced per *sub-element* as a result.
-illustration with a vec2, assuming RA==RT, e.g `sv.add/mr/vec2 r4, r4, r16`
+illustration with a vec2, assuming RA==RT, e.g `sv.add/mr/vec2 r4, r4, r16.v`
 
     for i in range(0, VL):
         # RA==RT in the instruction. does not have to be
@@ -622,28 +622,33 @@ like a traditional Vector Processor Reduction instruction.
 Example for a vec2:
 
     for i in range(VL):
-        iregs[RT+i] = op(iregs[RA+i].x, iregs[RA+i].y)
+        iregs[RT+i] = op(iregs[RA+i].x, iregs[RB+i].y)
 
 Example for a vec3:
 
     for i in range(VL):
-        iregs[RT+i] = op(iregs[RA+i].x, iregs[RA+i].y)
-        iregs[RT+i] = op(iregs[RT+i]  , iregs[RA+i].z)
+        iregs[RT+i] = op(iregs[RA+i].x, iregs[RB+i].y)
+        iregs[RT+i] = op(iregs[RT+i]  , iregs[RB+i].z)
 
 Example for a vec4:
 
     for i in range(VL):
-        iregs[RT+i] = op(iregs[RA+i].x, iregs[RA+i].y)
-        iregs[RT+i] = op(iregs[RT+i]  , iregs[RA+i].z)
-        iregs[RT+i] = op(iregs[RT+i]  , iregs[RA+i].w)
+        iregs[RT+i] = op(iregs[RA+i].x, iregs[RB+i].y)
+        iregs[RT+i] = op(iregs[RT+i]  , iregs[RB+i].z)
+        iregs[RT+i] = op(iregs[RT+i]  , iregs[RB+i].w)
 
 In this mode, when Rc=1 the Vector of CRs is as normal: each result
 element creates a corresponding CR element (for the final, reduced, result).
 
-Note that the destination (RT) is automatically used as an "Accumulator"
-register, and consequently the Sub-Vector Loop is interruptible.
-If RT is a Scalar then as usual the main VL Loop terminates at the
-first predicated element (or the first element if unpredicated).
+Note:
+
+1. that the destination (RT) is inherently used as an "Accumulator"
+   register, and consequently the Sub-Vector Loop is interruptible.
+   If RT is a Scalar then as usual the main VL Loop terminates at the
+   first predicated element (or the first element if unpredicated).
+2. that the Sub-Vector designation applies to RA and RB *but not RT*.
+3. that the number of operations executed is one less than the Sub-vector
+   length
 
 # Fail-on-first