1 files changed, 21 insertions, 0 deletions
diff --git a/libtommath/bn_s_mp_get_bit.c b/libtommath/bn_s_mp_get_bit.c
new file mode 100644
index 0000000..28598df
--- /dev/null
+++ b/libtommath/bn_s_mp_get_bit.c
@@ -0,0 +1,21 @@
+#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