1/*
2 * Copyright (c) 2017, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25#include "precompiled.hpp"
26#include "utilities/count_trailing_zeros.hpp"
27#include "utilities/globalDefinitions.hpp"
28#include "unittest.hpp"
29
30TEST(count_trailing_zeros, one_or_two_set_bits) {
31  unsigned i = 0;               // Position of a set bit.
32  for (uintx ix = 1; ix != 0; ix <<= 1, ++i) {
33    unsigned j = 0;             // Position of a set bit.
34    for (uintx jx = 1; jx != 0; jx <<= 1, ++j) {
35      uintx value = ix | jx;
36      EXPECT_EQ(MIN2(i, j), count_trailing_zeros(value))
37        << "value = " << value;
38    }
39  }
40}
41
42TEST(count_trailing_zeros, all_ones_followed_by_all_zeros) {
43  unsigned i = BitsPerWord - 1; // Index of most significant set bit.
44  uintx value = ~(uintx)0;
45  for ( ; value != 0; value >>= 1, --i) {
46    EXPECT_EQ(0u, count_trailing_zeros(value))
47      << "value = " << value;
48  }
49}
50
51TEST(count_trailing_zeros, all_zeros_followed_by_all_ones) {
52  unsigned i = 0;               // Index of least significant set bit.
53  uintx value = ~(uintx)0;
54  for ( ; value != 0; value <<= 1, ++i) {
55    EXPECT_EQ(i, count_trailing_zeros(value))
56      << "value = " << value;
57  }
58}
59