Import Tcl 8.6.10

libtommath/bn_mp_reduce_is_2k.c

@@ -0,0 +1,38 @@
+#include "tommath_private.h"
+#ifdef BN_MP_REDUCE_IS_2K_C
+/* LibTomMath, multiple-precision integer library -- Tom St Denis */
+/* SPDX-License-Identifier: Unlicense */
+
+/* determines if mp_reduce_2k can be used */
+mp_bool mp_reduce_is_2k(const mp_int *a)
+{
+   int ix, iy, iw;
+   mp_digit iz;
+
+   if (a->used == 0) {
+      return MP_NO;
+   } else if (a->used == 1) {
+      return MP_YES;
+   } else if (a->used > 1) {
+      iy = mp_count_bits(a);
+      iz = 1;
+      iw = 1;
+
+      /* Test every bit from the second digit up, must be 1 */
+      for (ix = MP_DIGIT_BIT; ix < iy; ix++) {
+         if ((a->dp[iw] & iz) == 0u) {
+            return MP_NO;
+         }
+         iz <<= 1;
+         if (iz > MP_DIGIT_MAX) {
+            ++iw;
+            iz = 1;
+         }
+      }
+      return MP_YES;
+   } else {
+      return MP_YES;
+   }
+}
+
+#endif