From 11da511c784eca003deb90c23570f0873954e0de Mon Sep 17 00:00:00 2001
From: Duncan Wilkie <antigravityd@gmail.com>
Date: Sat, 18 Nov 2023 06:11:09 -0600
Subject: Initial commit.

---
 gmp-6.3.0/mini-gmp/tests/t-invert.c | 141 ++++++++++++++++++++++++++++++++++++
 1 file changed, 141 insertions(+)
 create mode 100644 gmp-6.3.0/mini-gmp/tests/t-invert.c

(limited to 'gmp-6.3.0/mini-gmp/tests/t-invert.c')

diff --git a/gmp-6.3.0/mini-gmp/tests/t-invert.c b/gmp-6.3.0/mini-gmp/tests/t-invert.c
new file mode 100644
index 0000000..02e1731
--- /dev/null
+++ b/gmp-6.3.0/mini-gmp/tests/t-invert.c
@@ -0,0 +1,141 @@
+/*
+
+Copyright 2012, 2016 Free Software Foundation, Inc.
+
+This file is part of the GNU MP Library test suite.
+
+The GNU MP Library test suite is free software; you can redistribute it
+and/or modify it under the terms of the GNU General Public License as
+published by the Free Software Foundation; either version 3 of the License,
+or (at your option) any later version.
+
+The GNU MP Library test suite is distributed in the hope that it will be
+useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General
+Public License for more details.
+
+You should have received a copy of the GNU General Public License along with
+the GNU MP Library test suite.  If not, see https://www.gnu.org/licenses/.  */
+
+#include <assert.h>
+#include <limits.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+#include "testutils.h"
+
+#define GMP_LIMB_BITS (sizeof(mp_limb_t) * CHAR_BIT)
+
+#define COUNT 10000
+
+static void
+test_2by1(const mpz_t u)
+{
+  mpz_t m, p, t;
+  mp_limb_t tl;
+
+  mpz_init (p);
+
+  assert (mpz_size (u) == 1);
+
+  tl = mpn_invert_limb (u->_mp_d[0]);
+  mpz_roinit_n (t, &tl, 1);
+  mpz_init_set (m, t);
+  mpz_setbit (m, GMP_LIMB_BITS);
+
+  mpz_mul (p, m, u);
+
+  mpz_init (t);
+  mpz_setbit (t, 2* GMP_LIMB_BITS);
+  mpz_sub (t, t, p);
+
+  /* Should have 0 < B^2 - m u <= u */
+  if (mpz_sgn (t) <= 0 || mpz_cmp (t, u) > 0)
+    {
+      fprintf (stderr, "mpn_invert_limb failed:\n");
+      dump ("u", u);
+      dump ("m", m);
+      dump ("p", p);
+      dump ("t", t);
+      abort ();
+    }
+  mpz_clear (m);
+  mpz_clear (p);
+  mpz_clear (t);
+}
+
+static void
+test_3by2(const mpz_t u)
+{
+  mpz_t m, p, t;
+  mp_limb_t tl;
+
+  mpz_init (p);
+
+  assert (mpz_size (u) == 2);
+
+  tl = mpn_invert_3by2 (u->_mp_d[1], u->_mp_d[0]);
+  mpz_roinit_n (t, &tl, 1);
+  mpz_init_set (m, t);
+
+  mpz_setbit (m, GMP_LIMB_BITS);
+
+  mpz_mul (p, m, u);
+
+  mpz_init (t);
+  mpz_setbit (t, 3 * GMP_LIMB_BITS);
+  mpz_sub (t, t, p);
+
+  /* Should have 0 < B^3 - m u <= u */
+  if (mpz_sgn (t) <= 0 || mpz_cmp (t, u) > 0)
+    {
+      fprintf (stderr, "mpn_invert_3by2 failed:\n");
+      dump ("u", u);
+      dump ("m", m);
+      dump ("p", p);
+      dump ("t", t);
+      abort ();
+    }
+  mpz_clear (m);
+  mpz_clear (p);
+  mpz_clear (t);
+}
+
+void
+testmain (int argc, char **argv)
+{
+  unsigned i;
+  mpz_t u, m, p, t;
+
+  mpz_init (u);
+  mpz_init (m);
+  mpz_init (p);
+  mpz_init (t);
+
+  /* These values trigger 32-bit overflow of ql in mpn_invert_3by2. */
+  if (GMP_LIMB_BITS == 64)
+    {
+      mpz_set_str (u, "80007fff3ffe0000", 16);
+      test_2by1 (u);
+      mpz_set_str (u, "80007fff3ffe000000000000000003ff", 16);
+      test_3by2 (u);
+    }
+
+  for (i = 0; i < COUNT; i++)
+    {
+      mini_urandomb (u, GMP_LIMB_BITS);
+      mpz_setbit (u, GMP_LIMB_BITS -1);
+
+      test_2by1 (u);
+    }
+
+  for (i = 0; i < COUNT; i++)
+    {
+      mini_urandomb (u, 2*GMP_LIMB_BITS);
+      mpz_setbit (u, 2*GMP_LIMB_BITS -1);
+
+      test_3by2 (u);
+    }
+
+  mpz_clear (u);
+}
-- 
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