--- a/libtommath/bn_mp_montgomery_setup.c	Wed Feb 28 22:11:39 2018 +0800
+++ b/libtommath/bn_mp_montgomery_setup.c	Thu Oct 15 19:55:15 2020 +0800
@@ -1,59 +1,42 @@
-#include <tommath_private.h>
+#include "tommath_private.h"
 #ifdef BN_MP_MONTGOMERY_SETUP_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 */
 
 /* setups the montgomery reduction stuff */
-int
-mp_montgomery_setup (mp_int * n, mp_digit * rho)
+mp_err mp_montgomery_setup(const mp_int *n, mp_digit *rho)
 {
-  mp_digit x, b;
+   mp_digit x, b;
 
-/* fast inversion mod 2**k
- *
- * Based on the fact that
- *
- * XA = 1 (mod 2**n)  =>  (X(2-XA)) A = 1 (mod 2**2n)
- *                    =>  2*X*A - X*X*A*A = 1
- *                    =>  2*(1) - (1)     = 1
- */
-  b = n->dp[0];
+   /* fast inversion mod 2**k
+    *
+    * Based on the fact that
+    *
+    * XA = 1 (mod 2**n)  =>  (X(2-XA)) A = 1 (mod 2**2n)
+    *                    =>  2*X*A - X*X*A*A = 1
+    *                    =>  2*(1) - (1)     = 1
+    */
+   b = n->dp[0];
 
-  if ((b & 1) == 0) {
-    return MP_VAL;
-  }
+   if ((b & 1u) == 0u) {
+      return MP_VAL;
+   }
 
-  x = (((b + 2) & 4) << 1) + b; /* here x*a==1 mod 2**4 */
-  x *= 2 - (b * x);             /* here x*a==1 mod 2**8 */
+   x = (((b + 2u) & 4u) << 1) + b; /* here x*a==1 mod 2**4 */
+   x *= 2u - (b * x);              /* here x*a==1 mod 2**8 */
 #if !defined(MP_8BIT)
-  x *= 2 - (b * x);             /* here x*a==1 mod 2**16 */
+   x *= 2u - (b * x);              /* here x*a==1 mod 2**16 */
 #endif
 #if defined(MP_64BIT) || !(defined(MP_8BIT) || defined(MP_16BIT))
-  x *= 2 - (b * x);             /* here x*a==1 mod 2**32 */
+   x *= 2u - (b * x);              /* here x*a==1 mod 2**32 */
 #endif
 #ifdef MP_64BIT
-  x *= 2 - (b * x);             /* here x*a==1 mod 2**64 */
+   x *= 2u - (b * x);              /* here x*a==1 mod 2**64 */
 #endif
 
-  /* rho = -1/m mod b */
-  *rho = (mp_digit)(((mp_word)1 << ((mp_word) DIGIT_BIT)) - x) & MP_MASK;
+   /* rho = -1/m mod b */
+   *rho = (mp_digit)(((mp_word)1 << (mp_word)MP_DIGIT_BIT) - x) & MP_MASK;
 
-  return MP_OKAY;
+   return MP_OKAY;
 }
 #endif
-
-/* ref:         $Format:%D$ */
-/* git commit:  $Format:%H$ */
-/* commit time: $Format:%ai$ */