From eeb8cdccde497bc21e4108774e4951dd37d871eb Mon Sep 17 00:00:00 2001
From: Chris Conlon <chris@wolfssl.com>
Date: Fri, 5 Apr 2013 13:44:53 -0600
Subject: [PATCH] s_fp_sub() bug fix

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

diff --git a/ctaocrypt/src/tfm.c b/ctaocrypt/src/tfm.c
index 25372ded9..8f2c93f3e 100644
--- a/ctaocrypt/src/tfm.c
+++ b/ctaocrypt/src/tfm.c
@@ -169,7 +169,7 @@ void s_fp_sub(fp_int *a, fp_int *b, fp_int *c)
   for (; x < a->used; x++) {
      t         = ((fp_word)a->dp[x]) - t;
      c->dp[x]  = (fp_digit)t;
-     t         = (t >> DIGIT_BIT);
+     t         = (t >> DIGIT_BIT)&1;
    }
   for (; x < oldused; x++) {
      c->dp[x] = 0;