From 7c5483ba0b8f19617702e2983cd8910f72ea31f7 Mon Sep 17 00:00:00 2001
From: David Garske <david@wolfssl.com>
Date: Tue, 10 May 2016 15:17:40 -0700
Subject: [PATCH] Performance improvements in fp_mulmod, fp_submod and
 fp_submod to handle ALT_ECC_SIZE better. Revert fp_clear to fp_add_d, since
 it isn't required and slows it down.

---
 wolfcrypt/src/tfm.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/wolfcrypt/src/tfm.c b/wolfcrypt/src/tfm.c
index d5a0b8680..31bbd7c53 100644
--- a/wolfcrypt/src/tfm.c
+++ b/wolfcrypt/src/tfm.c
@@ -989,9 +989,12 @@ int fp_mulmod(fp_int *a, fp_int *b, fp_int *c, fp_int *d)
 
   fp_init(&t);
   fp_mul(a, b, &t);
+#ifdef ALT_ECC_SIZE
   err = fp_mod(&t, c, &t);
   fp_copy(&t, d);
-  fp_clear(&t);
+#else
+  err = fp_mod(&t, c, d);
+#endif
 
   return err;
 }
@@ -1004,9 +1007,12 @@ int fp_submod(fp_int *a, fp_int *b, fp_int *c, fp_int *d)
 
   fp_init(&t);
   fp_sub(a, b, &t);
+#ifdef ALT_ECC_SIZE
   err = fp_mod(&t, c, &t);
   fp_copy(&t, d);
-  fp_clear(&t);
+#else
+  err = fp_mod(&t, c, d);
+#endif
 
   return err;
 }
@@ -1019,9 +1025,12 @@ int fp_addmod(fp_int *a, fp_int *b, fp_int *c, fp_int *d)
 
   fp_init(&t);
   fp_add(a, b, &t);
+#ifdef ALT_ECC_SIZE
   err = fp_mod(&t, c, &t);
   fp_copy(&t, d);
-  fp_clear(&t);
+#else
+  err = fp_mod(&t, c, d);
+#endif
 
   return err;
 }
@@ -2833,7 +2842,6 @@ void fp_add_d(fp_int *a, fp_digit b, fp_int *c)
    fp_init(&tmp);
    fp_set(&tmp, b);
    fp_add(a, &tmp, c);
-   fp_clear(&tmp);
 }
 
 /* external compatibility */