/*
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* Copyright (C) 2011 Google Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package benchmarks.regression;
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public class IntegerBenchmark {
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public int timeLongSignumBranch(int reps) {
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int t = 0;
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for (int i = 0; i < reps; ++i) {
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t += signum1(-i);
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t += signum1(0);
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t += signum1(i);
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}
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return t;
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}
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public int timeLongSignumBranchFree(int reps) {
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int t = 0;
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for (int i = 0; i < reps; ++i) {
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t += signum2(-i);
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t += signum2(0);
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t += signum2(i);
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}
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return t;
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}
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private static int signum1(long v) {
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return v < 0 ? -1 : (v == 0 ? 0 : 1);
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}
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private static int signum2(long v) {
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return ((int)(v >> 63)) | (int) (-v >>> 63); // Hacker's delight 2-7
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}
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public int timeLongBitCount_BitSet(int reps) {
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int t = 0;
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for (int i = 0; i < reps; ++i) {
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t += pop((long) i);
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}
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return t;
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}
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private static int pop(long l) {
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int count = popX(l & 0xffffffffL);
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count += popX(l >>> 32);
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return count;
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}
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private static int popX(long x) {
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// BEGIN android-note
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// delegate to Integer.bitCount(i); consider using native code
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// END android-note
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x = x - ((x >>> 1) & 0x55555555);
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x = (x & 0x33333333) + ((x >>> 2) & 0x33333333);
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x = (x + (x >>> 4)) & 0x0f0f0f0f;
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x = x + (x >>> 8);
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x = x + (x >>> 16);
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return (int) x & 0x0000003f;
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}
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public int timeLongBitCount_2Int(int reps) {
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int t = 0;
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for (int i = 0; i < reps; ++i) {
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t += pop2((long) i);
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}
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return t;
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}
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private static int pop2(long l) {
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int count = Integer.bitCount((int) (l & 0xffffffffL));
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count += Integer.bitCount((int) (l >>> 32));
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return count;
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}
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public int timeLongBitCount_Long(int reps) {
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int t = 0;
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for (int i = 0; i < reps; ++i) {
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t += Long.bitCount((long) i);
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}
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return t;
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}
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/**
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* Table for Seal's algorithm for Number of Trailing Zeros. Hacker's Delight
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* online, Figure 5-18 (http://www.hackersdelight.org/revisions.pdf)
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* The entries whose value is -1 are never referenced.
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*/
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private static final byte[] NTZ_TABLE = {
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32, 0, 1, 12, 2, 6, -1, 13, 3, -1, 7, -1, -1, -1, -1, 14,
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10, 4, -1, -1, 8, -1, -1, 25, -1, -1, -1, -1, -1, 21, 27, 15,
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31, 11, 5, -1, -1, -1, -1, -1, 9, -1, -1, 24, -1, -1, 20, 26,
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30, -1, -1, -1, -1, 23, -1, 19, 29, -1, 22, 18, 28, 17, 16, -1
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};
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private static int numberOfTrailingZerosHD(int i) {
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// Seal's algorithm - Hacker's Delight 5-18
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i &= -i;
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i = (i << 4) + i; // x *= 17
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i = (i << 6) + i; // x *= 65
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i = (i << 16) - i; // x *= 65535
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return NTZ_TABLE[i >>> 26];
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}
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private static int numberOfTrailingZerosOL(int i) {
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return NTZ_TABLE[((i & -i) * 0x0450FBAF) >>> 26];
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}
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public int timeNumberOfTrailingZerosHD(int reps) {
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int t = 0;
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for (int i = 0; i < reps; ++i) {
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t += numberOfTrailingZerosHD(i);
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}
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return t;
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}
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public int timeNumberOfTrailingZerosOL(int reps) {
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int t = 0;
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for (int i = 0; i < reps; ++i) {
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t += numberOfTrailingZerosOL(i);
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}
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return t;
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}
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public int timeIntegerValueOf(int reps) throws Exception {
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String[] intStrings = new String[]{"0", "1", "12", "123", "1234", "12345",
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"123456", "1234567", "12345678"};
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int t = 0;
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for (int i = 0; i < reps; ++i) {
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for (int j = 0; j < intStrings.length; ++j) {
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t += Integer.valueOf(intStrings[j]);
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}
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}
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return t;
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}
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}
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