--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libtommath/bn_s_mp_prime_is_divisible.c	Thu Oct 15 19:55:15 2020 +0800
@@ -0,0 +1,35 @@
+#include "tommath_private.h"
+#ifdef BN_S_MP_PRIME_IS_DIVISIBLE_C
+/* LibTomMath, multiple-precision integer library -- Tom St Denis */
+/* SPDX-License-Identifier: Unlicense */
+
+/* determines if an integers is divisible by one
+ * of the first PRIME_SIZE primes or not
+ *
+ * sets result to 0 if not, 1 if yes
+ */
+mp_err s_mp_prime_is_divisible(const mp_int *a, mp_bool *result)
+{
+   int      ix;
+   mp_err   err;
+   mp_digit res;
+
+   /* default to not */
+   *result = MP_NO;
+
+   for (ix = 0; ix < PRIVATE_MP_PRIME_TAB_SIZE; ix++) {
+      /* what is a mod LBL_prime_tab[ix] */
+      if ((err = mp_mod_d(a, s_mp_prime_tab[ix], &res)) != MP_OKAY) {
+         return err;
+      }
+
+      /* is the residue zero? */
+      if (res == 0u) {
+         *result = MP_YES;
+         return MP_OKAY;
+      }
+   }
+
+   return MP_OKAY;
+}
+#endif