From bafb273a6c420ed150908387c3a220e6a3fc1a89 Mon Sep 17 00:00:00 2001
From: Sean Bowe <ewillbefull@gmail.com>
Date: Tue, 11 Jul 2017 23:49:33 -0600
Subject: [PATCH] Simplify doubling code during squaring routine.

---
 src/bls12_381/fq.rs | 50 +++++++++++----------------------------------
 src/bls12_381/fr.rs | 30 ++++++++-------------------
 2 files changed, 20 insertions(+), 60 deletions(-)

diff --git a/src/bls12_381/fq.rs b/src/bls12_381/fq.rs
index 403faedd5..67fe66ceb 100644
--- a/src/bls12_381/fq.rs
+++ b/src/bls12_381/fq.rs
@@ -627,45 +627,19 @@ impl Field for Fq {
         let mut carry = 0;
         let r9 = ::mac_with_carry(r9, (self.0).0[4], (self.0).0[5], &mut carry);
         let r10 = carry;
-        let tmp0 = r1 >> 63;
+
+        let r11 = r10 >> 63;
+        let r10 = (r10 << 1) | (r9 >> 63);
+        let r9 = (r9 << 1) | (r8 >> 63);
+        let r8 = (r8 << 1) | (r7 >> 63);
+        let r7 = (r7 << 1) | (r6 >> 63);
+        let r6 = (r6 << 1) | (r5 >> 63);
+        let r5 = (r5 << 1) | (r4 >> 63);
+        let r4 = (r4 << 1) | (r3 >> 63);
+        let r3 = (r3 << 1) | (r2 >> 63);
+        let r2 = (r2 << 1) | (r1 >> 63);
         let r1 = r1 << 1;
-        let tmp1 = r2 >> 63;
-        let r2 = r2 << 1;
-        let r2 = r2 | tmp0;
-        let tmp0 = tmp1;
-        let tmp1 = r3 >> 63;
-        let r3 = r3 << 1;
-        let r3 = r3 | tmp0;
-        let tmp0 = tmp1;
-        let tmp1 = r4 >> 63;
-        let r4 = r4 << 1;
-        let r4 = r4 | tmp0;
-        let tmp0 = tmp1;
-        let tmp1 = r5 >> 63;
-        let r5 = r5 << 1;
-        let r5 = r5 | tmp0;
-        let tmp0 = tmp1;
-        let tmp1 = r6 >> 63;
-        let r6 = r6 << 1;
-        let r6 = r6 | tmp0;
-        let tmp0 = tmp1;
-        let tmp1 = r7 >> 63;
-        let r7 = r7 << 1;
-        let r7 = r7 | tmp0;
-        let tmp0 = tmp1;
-        let tmp1 = r8 >> 63;
-        let r8 = r8 << 1;
-        let r8 = r8 | tmp0;
-        let tmp0 = tmp1;
-        let tmp1 = r9 >> 63;
-        let r9 = r9 << 1;
-        let r9 = r9 | tmp0;
-        let tmp0 = tmp1;
-        let tmp1 = r10 >> 63;
-        let r10 = r10 << 1;
-        let r10 = r10 | tmp0;
-        let tmp0 = tmp1;
-        let r11 = tmp0;
+
         let mut carry = 0;
         let r0 = ::mac_with_carry(0, (self.0).0[0], (self.0).0[0], &mut carry);
         let r1 = ::adc(r1, 0, &mut carry);
diff --git a/src/bls12_381/fr.rs b/src/bls12_381/fr.rs
index 98c93035c..55b7b582e 100644
--- a/src/bls12_381/fr.rs
+++ b/src/bls12_381/fr.rs
@@ -426,29 +426,15 @@ impl Field for Fr {
         let mut carry = 0;
         let r5 = ::mac_with_carry(r5, (self.0).0[2], (self.0).0[3], &mut carry);
         let r6 = carry;
-        let tmp0 = r1 >> 63;
+
+        let r7 = r6 >> 63;
+        let r6 = (r6 << 1) | (r5 >> 63);
+        let r5 = (r5 << 1) | (r4 >> 63);
+        let r4 = (r4 << 1) | (r3 >> 63);
+        let r3 = (r3 << 1) | (r2 >> 63);
+        let r2 = (r2 << 1) | (r1 >> 63);
         let r1 = r1 << 1;
-        let tmp1 = r2 >> 63;
-        let r2 = r2 << 1;
-        let r2 = r2 | tmp0;
-        let tmp0 = tmp1;
-        let tmp1 = r3 >> 63;
-        let r3 = r3 << 1;
-        let r3 = r3 | tmp0;
-        let tmp0 = tmp1;
-        let tmp1 = r4 >> 63;
-        let r4 = r4 << 1;
-        let r4 = r4 | tmp0;
-        let tmp0 = tmp1;
-        let tmp1 = r5 >> 63;
-        let r5 = r5 << 1;
-        let r5 = r5 | tmp0;
-        let tmp0 = tmp1;
-        let tmp1 = r6 >> 63;
-        let r6 = r6 << 1;
-        let r6 = r6 | tmp0;
-        let tmp0 = tmp1;
-        let r7 = tmp0;
+
         let mut carry = 0;
         let r0 = ::mac_with_carry(0, (self.0).0[0], (self.0).0[0], &mut carry);
         let r1 = ::adc(r1, 0, &mut carry);