+static int dh_bn_mod_exp(const DH *dh, BIGNUM *r,
+ const BIGNUM *a, const BIGNUM *p,
+ const BIGNUM *m, BN_CTX *ctx, BN_MONT_CTX *m_ctx)
+{
+ /*
+ * If a is only one word long and constant time is false, use the faster
+ * exponenentiation function.
+ */
+ if (a->top == 1 && ((dh->flags & DH_FLAG_NO_EXP_CONSTTIME) != 0)) {
+ BN_ULONG A = a->d[0];
+ return BN_mod_exp_mont_word(r, A, p, m, ctx, m_ctx);
+ } else
+ return BN_mod_exp_mont(r, a, p, m, ctx, m_ctx);
+}