--- a/libtommath/bn_mp_or.c	Thu Mar 21 23:28:59 2019 +0800
+++ b/libtommath/bn_mp_or.c	Fri Jun 26 21:07:34 2020 +0800
@@ -1,50 +1,56 @@
-#include <tommath_private.h>
+#include "tommath_private.h"
 #ifdef BN_MP_OR_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 */
 
-/* OR two ints together */
-int mp_or (mp_int * a, mp_int * b, mp_int * c)
+/* two complement or */
+mp_err mp_or(const mp_int *a, const mp_int *b, mp_int *c)
 {
-  int     res, ix, px;
-  mp_int  t, *x;
+   int used = MP_MAX(a->used, b->used) + 1, i;
+   mp_err err;
+   mp_digit ac = 1, bc = 1, cc = 1;
+   mp_sign csign = ((a->sign == MP_NEG) || (b->sign == MP_NEG)) ? MP_NEG : MP_ZPOS;
+
+   if (c->alloc < used) {
+      if ((err = mp_grow(c, used)) != MP_OKAY) {
+         return err;
+      }
+   }
+
+   for (i = 0; i < used; i++) {
+      mp_digit x, y;
+
+      /* convert to two complement if negative */
+      if (a->sign == MP_NEG) {
+         ac += (i >= a->used) ? MP_MASK : (~a->dp[i] & MP_MASK);
+         x = ac & MP_MASK;
+         ac >>= MP_DIGIT_BIT;
+      } else {
+         x = (i >= a->used) ? 0uL : a->dp[i];
+      }
 
-  if (a->used > b->used) {
-    if ((res = mp_init_copy (&t, a)) != MP_OKAY) {
-      return res;
-    }
-    px = b->used;
-    x = b;
-  } else {
-    if ((res = mp_init_copy (&t, b)) != MP_OKAY) {
-      return res;
-    }
-    px = a->used;
-    x = a;
-  }
+      /* convert to two complement if negative */
+      if (b->sign == MP_NEG) {
+         bc += (i >= b->used) ? MP_MASK : (~b->dp[i] & MP_MASK);
+         y = bc & MP_MASK;
+         bc >>= MP_DIGIT_BIT;
+      } else {
+         y = (i >= b->used) ? 0uL : b->dp[i];
+      }
+
+      c->dp[i] = x | y;
 
-  for (ix = 0; ix < px; ix++) {
-    t.dp[ix] |= x->dp[ix];
-  }
-  mp_clamp (&t);
-  mp_exch (c, &t);
-  mp_clear (&t);
-  return MP_OKAY;
+      /* convert to to sign-magnitude if negative */
+      if (csign == MP_NEG) {
+         cc += ~c->dp[i] & MP_MASK;
+         c->dp[i] = cc & MP_MASK;
+         cc >>= MP_DIGIT_BIT;
+      }
+   }
+
+   c->used = used;
+   c->sign = csign;
+   mp_clamp(c);
+   return MP_OKAY;
 }
 #endif
-
-/* ref:         $Format:%D$ */
-/* git commit:  $Format:%H$ */
-/* commit time: $Format:%ai$ */