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. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have 23 * questions. 24 */ 25 package jdk.incubator.vector; 26 27 import jdk.internal.vm.annotation.ForceInline; 28 import java.util.function.IntUnaryOperator; 29 30 /** 31 * A {@code VectorShuffle} represents an ordered immutable sequence of 32 * {@code int} values. A VectorShuffle can be used with a shuffle accepting 33 * vector operation to control the rearrangement of lane elements of input 34 * vectors 35 * <p> 36 * The number of values in the sequence is referred to as the shuffle 37 * {@link #length() length}. The length also corresponds to the number of 38 * shuffle lanes. The lane element at lane index {@code N} (from {@code 0}, 39 * inclusive, to length, exclusive) corresponds to the {@code N + 1}'th 40 * value in the sequence. 41 * A VectorShuffle and Vector of the same element type and shape have the same 42 * number of lanes. 43 * <p> 44 * A VectorShuffle describes how a lane element of a vector may cross lanes from 45 * its lane index, {@code i} say, to another lane index whose value is the 46 * shuffle's lane element at lane index {@code i}. VectorShuffle lane elements 47 * will be in the range of {@code 0} (inclusive) to the shuffle length 48 * (exclusive), and therefore cannot induce out of bounds errors when 49 * used with vectors operations and vectors of the same length. 50 * 51 * @param <E> the boxed element type of this mask 52 */ 53 public abstract class VectorShuffle<E> { 54 VectorShuffle() {} 55 56 /** 57 * Returns the species of this shuffle. 58 * 59 * @return the species of this shuffle 60 */ 61 public abstract VectorSpecies<E> species(); 62 63 /** 64 * Returns the number of shuffle lanes (the length). 65 * 66 * @return the number of shuffle lanes 67 */ 68 public int length() { return species().length(); } 69 70 /** 71 * Converts this shuffle to a shuffle of the given species of element type {@code F}. 72 * <p> 73 * For each shuffle lane, where {@code N} is the lane index, the 74 * shuffle element at index {@code N} is placed, unmodified, into the 75 * resulting shuffle at index {@code N}. 76 * 77 * @param species species of desired shuffle 78 * @param <F> the boxed element type of the species 79 * @return a shuffle converted by shape and element type 80 * @throws IllegalArgumentException if this shuffle length and the 81 * species length differ 82 */ 83 public abstract <F> VectorShuffle<F> cast(VectorSpecies<F> species); 84 85 /** 86 * Returns a shuffle of mapped indexes where each lane element is 87 * the result of applying a mapping function to the corresponding lane 88 * index. 89 * <p> 90 * Care should be taken to ensure VectorShuffle values produced from this 91 * method are consumed as constants to ensure optimal generation of 92 * code. For example, values held in static final fields or values 93 * held in loop constant local variables. 94 * <p> 95 * This method behaves as if a shuffle is created from an array of 96 * mapped indexes as follows: 97 * <pre>{@code 98 * int[] a = new int[species.length()]; 99 * for (int i = 0; i < a.length; i++) { 100 * a[i] = f.applyAsInt(i); 101 * } 102 * return VectorShuffle.fromValues(a); 103 * }</pre> 104 * 105 * @param species shuffle species 106 * @param f the lane index mapping function 107 * @return a shuffle of mapped indexes 108 */ 109 @ForceInline 110 public static <E> VectorShuffle<E> shuffle(VectorSpecies<E> species, IntUnaryOperator f) { 111 return ((AbstractSpecies<E>) species).shuffleFromOpFactory.apply(f); 112 } 113 114 /** 115 * Returns a shuffle where each lane element is the value of its 116 * corresponding lane index. 117 * <p> 118 * This method behaves as if a shuffle is created from an identity 119 * index mapping function as follows: 120 * <pre>{@code 121 * return VectorShuffle.shuffle(i -> i); 122 * }</pre> 123 * 124 * @param species shuffle species 125 * @return a shuffle of lane indexes 126 */ 127 @ForceInline 128 public static <E> VectorShuffle<E> shuffleIota(VectorSpecies<E> species) { 129 return ((AbstractSpecies<E>) species).shuffleFromOpFactory.apply(AbstractShuffle.IDENTITY); 130 } 131 132 /** 133 * Returns a shuffle with lane elements set to sequential {@code int} values starting from {@code start}. 134 * <p> 135 * This method behaves as if a shuffle is created from an identity 136 * index mapping function as follows: 137 * <pre>{@code 138 * return VectorShuffle.shuffle(i -> i + start); 139 * }</pre> 140 * 141 * @param species shuffle species 142 * @param start starting value of sequence 143 * @return a shuffle of lane indexes 144 */ 145 @ForceInline 146 public static <E> VectorShuffle<E> shuffleIota(VectorSpecies<E> species, int start) { 147 return ((AbstractSpecies<E>) species).shuffleFromOpFactory.apply(i -> i + start); 148 } 149 150 /** 151 * Returns a shuffle with lane elements set to sequential {@code int} values starting from {@code start} 152 * and looping around species length. 153 * <p> 154 * This method behaves as if a shuffle is created from an identity 155 * index mapping function as follows: 156 * <pre>{@code 157 * return VectorShuffle.shuffle(i -> (i + start) & (species.length() - 1)); 158 * }</pre> 159 * 160 * @param species shuffle species 161 * @param start starting value of sequence 162 * @return a shuffle of lane indexes 163 */ 164 @ForceInline 165 public static <E> VectorShuffle<E> shuffleOffset(VectorSpecies<E> species, int start) { 166 return ((AbstractSpecies<E>) species).shuffleFromOpFactory.apply(i -> (i + start) & (species.length() - 1)); 167 } 168 169 /** 170 * Returns a shuffle where each lane element is set to a given 171 * {@code int} value logically AND'ed by the species length minus one. 172 * <p> 173 * For each shuffle lane, where {@code N} is the shuffle lane index, the 174 * the {@code int} value at index {@code N} logically AND'ed by 175 * {@code species.length() - 1} is placed into the resulting shuffle at 176 * lane index {@code N}. 177 * 178 * @param species shuffle species 179 * @param ixs the given {@code int} values 180 * @return a shuffle where each lane element is set to a given 181 * {@code int} value 182 * @throws IndexOutOfBoundsException if the number of int values is 183 * {@code < species.length()} 184 */ 185 @ForceInline 186 public static <E> VectorShuffle<E> fromValues(VectorSpecies<E> species, int... ixs) { 187 return ((AbstractSpecies<E>) species).shuffleFromArrayFactory.apply(ixs, 0); 188 } 189 190 /** 191 * Loads a shuffle from an {@code int} array starting at an offset. 192 * <p> 193 * For each shuffle lane, where {@code N} is the shuffle lane index, the 194 * array element at index {@code i + N} logically AND'ed by 195 * {@code species.length() - 1} is placed into the resulting shuffle at lane 196 * index {@code N}. 197 * 198 * @param species shuffle species 199 * @param ixs the {@code int} array 200 * @param offset the offset into the array 201 * @return a shuffle loaded from the {@code int} array 202 * @throws IndexOutOfBoundsException if {@code offset < 0}, or 203 * {@code offset > a.length - species.length()} 204 */ 205 @ForceInline 206 public static <E> VectorShuffle<E> fromArray(VectorSpecies<E> species, int[] ixs, int offset) { 207 return ((AbstractSpecies<E>) species).shuffleFromArrayFactory.apply(ixs, offset); 208 } 209 210 /** 211 * Returns an {@code int} array containing the lane elements of this 212 * shuffle. 213 * <p> 214 * This method behaves as if it {@link #intoArray(int[], int)} stores} 215 * this shuffle into an allocated array and returns that array as 216 * follows: 217 * <pre>{@code 218 * int[] a = new int[this.length()]; 219 * VectorShuffle.intoArray(a, 0); 220 * return a; 221 * }</pre> 222 * 223 * @return an array containing the the lane elements of this vector 224 */ 225 public abstract int[] toArray(); 226 227 /** 228 * Stores this shuffle into an {@code int} array starting at offset. 229 * <p> 230 * For each shuffle lane, where {@code N} is the shuffle lane index, 231 * the lane element at index {@code N} is stored into the array at index 232 * {@code i + N}. 233 * 234 * @param a the array 235 * @param offset the offset into the array 236 * @throws IndexOutOfBoundsException if {@code i < 0}, or 237 * {@code offset > a.length - this.length()} 238 */ 239 public abstract void intoArray(int[] a, int offset); 240 241 /** 242 * Converts this shuffle into a vector, creating a vector from shuffle 243 * lane elements (int values) cast to the vector element type. 244 * <p> 245 * This method behaves as if it returns the result of creating a 246 * vector given an {@code int} array obtained from this shuffle's 247 * lane elements, as follows: 248 * <pre>{@code 249 * int[] sa = this.toArray(); 250 * $type$[] va = new $type$[a.length]; 251 * for (int i = 0; i < a.length; i++) { 252 * va[i] = ($type$) sa[i]; 253 * } 254 * return IntVector.fromArray(va, 0); 255 * }</pre> 256 * 257 * @return a vector representation of this shuffle 258 */ 259 public abstract Vector<E> toVector(); 260 261 /** 262 * Gets the {@code int} lane element at lane index {@code i} 263 * 264 * @param i the lane index 265 * @return the {@code int} lane element at lane index {@code i} 266 */ 267 public int lane(int i) { return toArray()[i]; } 268 269 /** 270 * Rearranges the lane elements of this shuffle selecting lane indexes 271 * controlled by another shuffle. 272 * <p> 273 * For each lane of the specified shuffle, at lane index {@code N} with lane 274 * element {@code I}, the lane element at {@code I} from this shuffle is 275 * selected and placed into the resulting shuffle at {@code N}. 276 * 277 * @param s the shuffle controlling lane index selection 278 * @return the rearrangement of the lane elements of this shuffle 279 */ 280 public abstract VectorShuffle<E> rearrange(VectorShuffle<E> s); 281 }