--- a/libtommath/bn_mp_reduce_is_2k.c	Wed Feb 28 22:11:39 2018 +0800
+++ b/libtommath/bn_mp_reduce_is_2k.c	Thu Oct 15 19:55:15 2020 +0800
@@ -1,26 +1,14 @@
-#include <tommath_private.h>
+#include "tommath_private.h"
 #ifdef BN_MP_REDUCE_IS_2K_C
-/* LibTomMath, multiple-precision integer library -- Tom St Denis
- *
- * LibTomMath is a library that provides multiple-precision
- * integer arithmetic as well as number theoretic functionality.
- *
- * The library was designed directly after the MPI library by
- * Michael Fromberger but has been written from scratch with
- * additional optimizations in place.
- *
- * The library is free for all purposes without any express
- * guarantee it works.
- *
- * Tom St Denis, [email protected], http://libtom.org
- */
+/* LibTomMath, multiple-precision integer library -- Tom St Denis */
+/* SPDX-License-Identifier: Unlicense */
 
 /* determines if mp_reduce_2k can be used */
-int mp_reduce_is_2k(mp_int *a)
+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) {
@@ -29,24 +17,22 @@
       iy = mp_count_bits(a);
       iz = 1;
       iw = 1;
-    
+
       /* Test every bit from the second digit up, must be 1 */
-      for (ix = DIGIT_BIT; ix < iy; ix++) {
-          if ((a->dp[iw] & iz) == 0) {
-             return MP_NO;
-          }
-          iz <<= 1;
-          if (iz > (mp_digit)MP_MASK) {
-             ++iw;
-             iz = 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;
    }
-   return MP_YES;
 }
 
 #endif
-
-/* ref:         $Format:%D$ */
-/* git commit:  $Format:%H$ */
-/* commit time: $Format:%ai$ */