From: lkcl <lkcl@web>
Date: Mon, 21 Dec 2020 14:17:49 +0000 (+0000)
Subject: (no commit message)
X-Git-Tag: convert-csv-opcode-to-binary~1088
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=3b342212b156053d897409bcf1e52da2b10b3679;p=libreriscv.git

---

diff --git a/openpower/sv/svp_rewrite/svp64.mdwn b/openpower/sv/svp_rewrite/svp64.mdwn
index d4d512994..aa9219501 100644
--- a/openpower/sv/svp_rewrite/svp64.mdwn
+++ b/openpower/sv/svp_rewrite/svp64.mdwn
@@ -655,9 +655,10 @@ One extremely important aspect of ffirst is:
 
 ## pred-result mode
 
-This mode merges common CR testing with predication, saving on instruction count
+This mode merges common CR testing with predication, saving on instruction count. Below is the pseudocode excluding predicate zeroing and elwidth overrides.
 
     for i in range(VL):
+        # predication test, skip all masked out elements.
         if predicate_masked_out(i):
              continue
         result = op(iregs[RA+i], iregs[RB+i])
@@ -674,6 +675,8 @@ This mode merges common CR testing with predication, saving on instruction count
 The reason for allowing the CR element to be stored is so that post-analysis
 of the CR Vector may be carried out.  For example: Saturation may have occurred (and been prevented from updating, by the test) but it is desirable to know *which* elements fail saturation.
 
+Note that predication is still respected: predicate zeroing is slightly different: elements that fail the CR test *or* are masked out are zero'd.
+
 ## CR Operations
 
 CRs are slightly more involved than INT or FP registers due to the