From 7061ea95a46e2e5700d61d52b4c2d3d86cc989f8 Mon Sep 17 00:00:00 2001
From: Anton Bukov <k06aaa@gmail.com>
Date: Sat, 19 Oct 2019 22:11:00 +0300
Subject: [PATCH] Simplify overflow check for squaring in rpow(x,n,base)

---
 src/jug.sol | 2 +-
 src/pot.sol | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/jug.sol b/src/jug.sol
index 3d4e7207..44a6d22a 100644
--- a/src/jug.sol
+++ b/src/jug.sol
@@ -47,7 +47,7 @@ contract Jug is DSNote {
                     let half := div(b, 2)  // for rounding.
                     for { n := div(n, 2) } n { n := div(n,2) } {
                         let xx := mul(x, x)
-                        if iszero(eq(div(xx, x), x)) { revert(0,0) }
+                        if shr(x, 128) { revert(0,0) }
                         let xxRound := add(xx, half)
                         if lt(xxRound, xx) { revert(0,0) }
                         x := div(xxRound, b)
diff --git a/src/pot.sol b/src/pot.sol
index 3df066ea..e8c31016 100644
--- a/src/pot.sol
+++ b/src/pot.sol
@@ -85,7 +85,7 @@ contract Pot is DSNote {
                     let half := div(base, 2)  // for rounding.
                     for { n := div(n, 2) } n { n := div(n,2) } {
                         let xx := mul(x, x)
-                        if iszero(eq(div(xx, x), x)) { revert(0,0) }
+                        if shr(x, 128) { revert(0,0) }
                         let xxRound := add(xx, half)
                         if lt(xxRound, xx) { revert(0,0) }
                         x := div(xxRound, base)