--- /dev/null
+#include "tommath_private.h"
+#ifdef BN_S_MP_GET_BIT_C
+
+/* LibTomMath, multiple-precision integer library -- Tom St Denis */
+/* SPDX-License-Identifier: Unlicense */
+
+/* Get bit at position b and return MP_YES if the bit is 1, MP_NO if it is 0 */
+mp_bool s_mp_get_bit(const mp_int *a, unsigned int b)
+{
+ mp_digit bit;
+ int limb = (int)(b / MP_DIGIT_BIT);
+
+ if (limb >= a->used) {
+ return MP_NO;
+ }
+
+ bit = (mp_digit)1 << (b % MP_DIGIT_BIT);
+ return ((a->dp[limb] & bit) != 0u) ? MP_YES : MP_NO;
+}
+
+#endif