--- a/libtommath/bn_mp_sqrt.c	Tue May 26 23:27:26 2020 +0800
+++ b/libtommath/bn_mp_sqrt.c	Tue May 26 17:36:47 2020 +0200
@@ -1,21 +1,12 @@
 #include "tommath_private.h"
 #ifdef BN_MP_SQRT_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 */
 
 /* this function is less generic than mp_n_root, simpler and faster */
-int mp_sqrt(const mp_int *arg, mp_int *ret)
+mp_err mp_sqrt(const mp_int *arg, mp_int *ret)
 {
-   int res;
+   mp_err err;
    mp_int t1, t2;
 
    /* must be positive */
@@ -24,16 +15,16 @@
    }
 
    /* easy out */
-   if (mp_iszero(arg) == MP_YES) {
+   if (MP_IS_ZERO(arg)) {
       mp_zero(ret);
       return MP_OKAY;
    }
 
-   if ((res = mp_init_copy(&t1, arg)) != MP_OKAY) {
-      return res;
+   if ((err = mp_init_copy(&t1, arg)) != MP_OKAY) {
+      return err;
    }
 
-   if ((res = mp_init(&t2)) != MP_OKAY) {
+   if ((err = mp_init(&t2)) != MP_OKAY) {
       goto E2;
    }
 
@@ -41,24 +32,24 @@
    mp_rshd(&t1, t1.used/2);
 
    /* t1 > 0  */
-   if ((res = mp_div(arg, &t1, &t2, NULL)) != MP_OKAY) {
+   if ((err = mp_div(arg, &t1, &t2, NULL)) != MP_OKAY) {
       goto E1;
    }
-   if ((res = mp_add(&t1, &t2, &t1)) != MP_OKAY) {
+   if ((err = mp_add(&t1, &t2, &t1)) != MP_OKAY) {
       goto E1;
    }
-   if ((res = mp_div_2(&t1, &t1)) != MP_OKAY) {
+   if ((err = mp_div_2(&t1, &t1)) != MP_OKAY) {
       goto E1;
    }
    /* And now t1 > sqrt(arg) */
    do {
-      if ((res = mp_div(arg, &t1, &t2, NULL)) != MP_OKAY) {
+      if ((err = mp_div(arg, &t1, &t2, NULL)) != MP_OKAY) {
          goto E1;
       }
-      if ((res = mp_add(&t1, &t2, &t1)) != MP_OKAY) {
+      if ((err = mp_add(&t1, &t2, &t1)) != MP_OKAY) {
          goto E1;
       }
-      if ((res = mp_div_2(&t1, &t1)) != MP_OKAY) {
+      if ((err = mp_div_2(&t1, &t1)) != MP_OKAY) {
          goto E1;
       }
       /* t1 >= sqrt(arg) >= t2 at this point */
@@ -70,11 +61,7 @@
    mp_clear(&t2);
 E2:
    mp_clear(&t1);
-   return res;
+   return err;
 }
 
 #endif
-
-/* ref:         HEAD -> master, tag: v1.1.0 */
-/* git commit:  08549ad6bc8b0cede0b357a9c341c5c6473a9c55 */
-/* commit time: 2019-01-28 20:32:32 +0100 */