From ef1284165f8605ae9c6e76268b051eb7eec89aea Mon Sep 17 00:00:00 2001
From: Daniel Pouzzner <douzzer@wolfssl.com>
Date: Thu, 10 Dec 2020 23:50:30 -0600
Subject: [PATCH] wolfcrypt/src/integer.c: fix sub-byte clearing step of
 mp_mod_2d() to work when DIGIT_BIT != sizeof(mp_digit)*8.

---
 wolfcrypt/src/integer.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/wolfcrypt/src/integer.c b/wolfcrypt/src/integer.c
index 53f8f2f59..badf70994 100644
--- a/wolfcrypt/src/integer.c
+++ b/wolfcrypt/src/integer.c
@@ -686,7 +686,7 @@ int mp_mod_2d (mp_int * a, int b, mp_int * c)
   /* clear the digit that is not completely outside/inside the modulus */
   x = DIGIT_BIT - (b % DIGIT_BIT);
   if (x != DIGIT_BIT) {
-    c->dp[b / DIGIT_BIT] &= ~((mp_digit)0) >> x;
+    c->dp[b / DIGIT_BIT] &= ~((mp_digit)0) >> (x + ((sizeof(mp_digit)*8) - DIGIT_BIT));
   }
   mp_clamp (c);
   return MP_OKAY;