--- a/libtommath/bn_mp_grow.c	Tue May 26 23:27:26 2020 +0800
+++ b/libtommath/bn_mp_grow.c	Tue May 26 17:36:47 2020 +0200
@@ -1,35 +1,25 @@
 #include "tommath_private.h"
 #ifdef BN_MP_GROW_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.
- *
- * SPDX-License-Identifier: Unlicense
- */
+/* LibTomMath, multiple-precision integer library -- Tom St Denis */
+/* SPDX-License-Identifier: Unlicense */
 
 /* grow as required */
-int mp_grow(mp_int *a, int size)
+mp_err mp_grow(mp_int *a, int size)
 {
    int     i;
    mp_digit *tmp;
 
    /* if the alloc size is smaller alloc more ram */
    if (a->alloc < size) {
-      /* ensure there are always at least MP_PREC digits extra on top */
-      size += (MP_PREC * 2) - (size % MP_PREC);
-
       /* reallocate the array a->dp
        *
        * We store the return in a temporary variable
        * in case the operation failed we don't want
        * to overwrite the dp member of a.
        */
-      tmp = OPT_CAST(mp_digit) XREALLOC(a->dp, sizeof(mp_digit) * (size_t)size);
+      tmp = (mp_digit *) MP_REALLOC(a->dp,
+                                    (size_t)a->alloc * sizeof(mp_digit),
+                                    (size_t)size * sizeof(mp_digit));
       if (tmp == NULL) {
          /* reallocation failed but "a" is still valid [can be freed] */
          return MP_MEM;
@@ -41,14 +31,8 @@
       /* zero excess digits */
       i        = a->alloc;
       a->alloc = size;
-      for (; i < a->alloc; i++) {
-         a->dp[i] = 0;
-      }
+      MP_ZERO_DIGITS(a->dp + i, a->alloc - i);
    }
    return MP_OKAY;
 }
 #endif
-
-/* ref:         HEAD -> master, tag: v1.1.0 */
-/* git commit:  08549ad6bc8b0cede0b357a9c341c5c6473a9c55 */
-/* commit time: 2019-01-28 20:32:32 +0100 */