From: Loup Vaillant <loup@loup-vaillant.fr>
Date: Thu, 13 Aug 2020 14:34:51 +0000 (+0200)
Subject: Small carry simplification
X-Git-Url: https://git.codecow.com/?a=commitdiff_plain;h=63a75c6d8ab03a0a48f8157daf49df10a5f2ec0f;p=Monocypher.git

Small carry simplification
---

diff --git a/src/monocypher.c b/src/monocypher.c
index ef052fb..9f4715e 100644
--- a/src/monocypher.c
+++ b/src/monocypher.c
@@ -1143,8 +1143,7 @@ static void fe_tobytes(u8 s[32], const fe h)
         q += t[2*i  ]; q >>= 26;
         q += t[2*i+1]; q >>= 25;
     }
-    t[0] += 19 * q;
-    q = 0;
+    q *= 19;  // Shift carry back to the begining
     FOR (i, 0, 5) {
         t[i*2  ] += q;  q = t[i*2  ] >> 26;  t[i*2  ] -= q * ((i32)1 << 26);
         t[i*2+1] += q;  q = t[i*2+1] >> 25;  t[i*2+1] -= q * ((i32)1 << 25);