From: lkcl <lkcl@web>
Date: Wed, 27 Apr 2022 15:26:06 +0000 (+0100)
Subject: (no commit message)
X-Git-Tag: opf_rfc_ls005_v1~2553
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=7e934f67f3d8be74288bfd813f1df05e54591b12;p=libreriscv.git

---

diff --git a/openpower/sv/biginteger/analysis.mdwn b/openpower/sv/biginteger/analysis.mdwn
index 719755e34..0ed378f06 100644
--- a/openpower/sv/biginteger/analysis.mdwn
+++ b/openpower/sv/biginteger/analysis.mdwn
@@ -477,8 +477,11 @@ the dividend then the result may not fit into 64 bit.  Knuth's
 original algorithm detects overflow and manually places 0xffffffff
 (all ones) into `qhat`. With there being so many operands already
 in  `divrem2du`  a  `cmpl` instruction can be used instead to detect
-the overflow. This saves having to add an Rc=1 or OE.
+the overflow. This saves having to add an Rc=1 or OE=1 mode when
+the available space in VA-Form EXT04 is extremely limited.
 
 Looking closely at the loop however we can see that overflow 
 will not occur. The initial value k is zero, and on subsequent iterations
-new k, being the modulo, is always less than the divisor
+new k, being the modulo, is always less than the divisor. Thus the
+condition (the loop invariant) `RC < RA` is preserved, as long as RC
+starts at zero.