From 416c5401fcf4ca566d9ea74b826d2eeb28d58dce Mon Sep 17 00:00:00 2001
From: lkcl <lkcl@web>
Date: Tue, 19 Apr 2022 18:17:35 +0100
Subject: [PATCH]

---
 openpower/sv/biginteger.mdwn | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/openpower/sv/biginteger.mdwn b/openpower/sv/biginteger.mdwn
index 670c8dc24..9a7fb0388 100644
--- a/openpower/sv/biginteger.mdwn
+++ b/openpower/sv/biginteger.mdwn
@@ -90,4 +90,15 @@ purpose.
     RT = lowerhalf(product)
     RC = upperhalf(product)
 
-Successive iterations effectively use RC as a 64-bit carry.
+Successive iterations effectively use RC as a 64-bit carry, and
+as noted by Intel in their notes on mulx,
+RA*RB+RC+RD cannot overflow, so does not require
+setting an additional CA flag.
+
+## Divide
+
+The simplest implementation of big-int divide is the standard textbook
+"Long Division", set with RADIX 64 instead of Base 10. Donald Knuth's
+Algorithm D performs estimates which, if wrong, are compensated for
+afterwards.  Essentially however there are three phases:
+
-- 
2.30.2