--- a/libtommath/bn_mp_sqr.c	Wed Feb 28 22:11:39 2018 +0800
+++ b/libtommath/bn_mp_sqr.c	Thu Oct 15 19:55:15 2020 +0800
@@ -1,60 +1,28 @@
-#include <tommath_private.h>
+#include "tommath_private.h"
 #ifdef BN_MP_SQR_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 */
 
 /* computes b = a*a */
-int
-mp_sqr (mp_int * a, mp_int * b)
+mp_err mp_sqr(const mp_int *a, mp_int *b)
 {
-  int     res;
-
-#ifdef BN_MP_TOOM_SQR_C
-  /* use Toom-Cook? */
-  if (a->used >= TOOM_SQR_CUTOFF) {
-    res = mp_toom_sqr(a, b);
-  /* Karatsuba? */
-  } else 
-#endif
-#ifdef BN_MP_KARATSUBA_SQR_C
-  if (a->used >= KARATSUBA_SQR_CUTOFF) {
-    res = mp_karatsuba_sqr (a, b);
-  } else 
-#endif
-  {
-#ifdef BN_FAST_S_MP_SQR_C
-    /* can we use the fast comba multiplier? */
-    if ((((a->used * 2) + 1) < MP_WARRAY) &&
-         (a->used <
-         (1 << (((sizeof(mp_word) * CHAR_BIT) - (2 * DIGIT_BIT)) - 1)))) {
-      res = fast_s_mp_sqr (a, b);
-    } else
-#endif
-    {
-#ifdef BN_S_MP_SQR_C
-      res = s_mp_sqr (a, b);
-#else
-      res = MP_VAL;
-#endif
-    }
-  }
-  b->sign = MP_ZPOS;
-  return res;
+   mp_err err;
+   if (MP_HAS(S_MP_TOOM_SQR) && /* use Toom-Cook? */
+       (a->used >= MP_TOOM_SQR_CUTOFF)) {
+      err = s_mp_toom_sqr(a, b);
+   } else if (MP_HAS(S_MP_KARATSUBA_SQR) &&  /* Karatsuba? */
+              (a->used >= MP_KARATSUBA_SQR_CUTOFF)) {
+      err = s_mp_karatsuba_sqr(a, b);
+   } else if (MP_HAS(S_MP_SQR_FAST) && /* can we use the fast comba multiplier? */
+              (((a->used * 2) + 1) < MP_WARRAY) &&
+              (a->used < (MP_MAXFAST / 2))) {
+      err = s_mp_sqr_fast(a, b);
+   } else if (MP_HAS(S_MP_SQR)) {
+      err = s_mp_sqr(a, b);
+   } else {
+      err = MP_VAL;
+   }
+   b->sign = MP_ZPOS;
+   return err;
 }
 #endif
-
-/* ref:         $Format:%D$ */
-/* git commit:  $Format:%H$ */
-/* commit time: $Format:%ai$ */