--- a/libtommath/bn_mp_mul_2d.c	Wed Feb 28 22:11:39 2018 +0800
+++ b/libtommath/bn_mp_mul_2d.c	Thu Oct 15 19:55:15 2020 +0800
@@ -1,85 +1,69 @@
-#include <tommath_private.h>
+#include "tommath_private.h"
 #ifdef BN_MP_MUL_2D_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 */
 
 /* shift left by a certain bit count */
-int mp_mul_2d (mp_int * a, int b, mp_int * c)
+mp_err mp_mul_2d(const mp_int *a, int b, mp_int *c)
 {
-  mp_digit d;
-  int      res;
+   mp_digit d;
+   mp_err   err;
 
-  /* copy */
-  if (a != c) {
-     if ((res = mp_copy (a, c)) != MP_OKAY) {
-       return res;
-     }
-  }
+   /* copy */
+   if (a != c) {
+      if ((err = mp_copy(a, c)) != MP_OKAY) {
+         return err;
+      }
+   }
 
-  if (c->alloc < (int)(c->used + (b / DIGIT_BIT) + 1)) {
-     if ((res = mp_grow (c, c->used + (b / DIGIT_BIT) + 1)) != MP_OKAY) {
-       return res;
-     }
-  }
+   if (c->alloc < (c->used + (b / MP_DIGIT_BIT) + 1)) {
+      if ((err = mp_grow(c, c->used + (b / MP_DIGIT_BIT) + 1)) != MP_OKAY) {
+         return err;
+      }
+   }
 
-  /* shift by as many digits in the bit count */
-  if (b >= (int)DIGIT_BIT) {
-    if ((res = mp_lshd (c, b / DIGIT_BIT)) != MP_OKAY) {
-      return res;
-    }
-  }
+   /* shift by as many digits in the bit count */
+   if (b >= MP_DIGIT_BIT) {
+      if ((err = mp_lshd(c, b / MP_DIGIT_BIT)) != MP_OKAY) {
+         return err;
+      }
+   }
 
-  /* shift any bit count < DIGIT_BIT */
-  d = (mp_digit) (b % DIGIT_BIT);
-  if (d != 0) {
-    mp_digit *tmpc, shift, mask, r, rr;
-    int x;
+   /* shift any bit count < MP_DIGIT_BIT */
+   d = (mp_digit)(b % MP_DIGIT_BIT);
+   if (d != 0u) {
+      mp_digit *tmpc, shift, mask, r, rr;
+      int x;
 
-    /* bitmask for carries */
-    mask = (((mp_digit)1) << d) - 1;
+      /* bitmask for carries */
+      mask = ((mp_digit)1 << d) - (mp_digit)1;
 
-    /* shift for msbs */
-    shift = DIGIT_BIT - d;
+      /* shift for msbs */
+      shift = (mp_digit)MP_DIGIT_BIT - d;
 
-    /* alias */
-    tmpc = c->dp;
+      /* alias */
+      tmpc = c->dp;
 
-    /* carry */
-    r    = 0;
-    for (x = 0; x < c->used; x++) {
-      /* get the higher bits of the current word */
-      rr = (*tmpc >> shift) & mask;
+      /* carry */
+      r    = 0;
+      for (x = 0; x < c->used; x++) {
+         /* get the higher bits of the current word */
+         rr = (*tmpc >> shift) & mask;
 
-      /* shift the current word and OR in the carry */
-      *tmpc = ((*tmpc << d) | r) & MP_MASK;
-      ++tmpc;
+         /* shift the current word and OR in the carry */
+         *tmpc = ((*tmpc << d) | r) & MP_MASK;
+         ++tmpc;
+
+         /* set the carry to the carry bits of the current word */
+         r = rr;
+      }
 
-      /* set the carry to the carry bits of the current word */
-      r = rr;
-    }
-    
-    /* set final carry */
-    if (r != 0) {
-       c->dp[(c->used)++] = r;
-    }
-  }
-  mp_clamp (c);
-  return MP_OKAY;
+      /* set final carry */
+      if (r != 0u) {
+         c->dp[(c->used)++] = r;
+      }
+   }
+   mp_clamp(c);
+   return MP_OKAY;
 }
 #endif
-
-/* ref:         $Format:%D$ */
-/* git commit:  $Format:%H$ */
-/* commit time: $Format:%ai$ */