1 /*
   2  * Copyright (c) 2012, 2018, 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  */
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  41 package jdk.internal.vm.compiler.word;
  42 
  43 import jdk.internal.vm.compiler.word.impl.WordBoxFactory;
  44 import jdk.internal.vm.compiler.word.impl.WordFactoryOpcode;
  45 import jdk.internal.vm.compiler.word.impl.WordFactoryOperation;
  46 
  47 /**
  48  * Provides factory method to create machine-word-sized values.
  49  *
  50  * @since 1.0
  51  */
  52 public final class WordFactory {
  53 
  54     private WordFactory() {
  55     }
  56 
  57     /**
  58      * The constant 0, i.e., the word with no bits set. There is no difference between a signed and
  59      * unsigned zero.
  60      *
  61      * @return the constant 0.
  62      *
  63      * @since 1.0
  64      */
  65     @WordFactoryOperation(opcode = WordFactoryOpcode.ZERO)
  66     public static <T extends WordBase> T zero() {
  67         return WordBoxFactory.box(0L);
  68     }
  69 
  70     /**
  71      * The null pointer, i.e., the pointer with no bits set. There is no difference to a signed or
  72      * unsigned {@link #zero}.
  73      *
  74      * @return the null pointer.
  75      *
  76      * @since 1.0
  77      */
  78     @WordFactoryOperation(opcode = WordFactoryOpcode.ZERO)
  79     public static <T extends PointerBase> T nullPointer() {
  80         return WordBoxFactory.box(0L);
  81     }
  82 
  83     /**
  84      * Unsafe conversion from a Java long value to a Word. The parameter is treated as an unsigned
  85      * 64-bit value (in contrast to the semantics of a Java long).
  86      *
  87      * @param val a 64 bit unsigned value
  88      * @return the value cast to Word
  89      *
  90      * @since 1.0
  91      */
  92     @WordFactoryOperation(opcode = WordFactoryOpcode.FROM_UNSIGNED)
  93     public static <T extends UnsignedWord> T unsigned(long val) {
  94         return WordBoxFactory.box(val);
  95     }
  96 
  97     /**
  98      * Unsafe conversion from a Java long value to a {@link PointerBase pointer}. The parameter is
  99      * treated as an unsigned 64-bit value (in contrast to the semantics of a Java long).
 100      *
 101      * @param val a 64 bit unsigned value
 102      * @return the value cast to PointerBase
 103      *
 104      * @since 1.0
 105      */
 106     @WordFactoryOperation(opcode = WordFactoryOpcode.FROM_UNSIGNED)
 107     public static <T extends PointerBase> T pointer(long val) {
 108         return WordBoxFactory.box(val);
 109     }
 110 
 111     /**
 112      * Unsafe conversion from a Java int value to a Word. The parameter is treated as an unsigned
 113      * 32-bit value (in contrast to the semantics of a Java int).
 114      *
 115      * @param val a 32 bit unsigned value
 116      * @return the value cast to Word
 117      *
 118      * @since 1.0
 119      */
 120     @WordFactoryOperation(opcode = WordFactoryOpcode.FROM_UNSIGNED)
 121     public static <T extends UnsignedWord> T unsigned(int val) {
 122         return WordBoxFactory.box(val & 0xffffffffL);
 123     }
 124 
 125     /**
 126      * Unsafe conversion from a Java long value to a Word. The parameter is treated as a signed
 127      * 64-bit value (unchanged semantics of a Java long).
 128      *
 129      * @param val a 64 bit signed value
 130      * @return the value cast to Word
 131      *
 132      * @since 1.0
 133      */
 134     @WordFactoryOperation(opcode = WordFactoryOpcode.FROM_SIGNED)
 135     public static <T extends SignedWord> T signed(long val) {
 136         return WordBoxFactory.box(val);
 137     }
 138 
 139     /**
 140      * Unsafe conversion from a Java int value to a Word. The parameter is treated as a signed
 141      * 32-bit value (unchanged semantics of a Java int).
 142      *
 143      * @param val a 32 bit signed value
 144      * @return the value cast to Word
 145      *
 146      * @since 1.0
 147      */
 148     @WordFactoryOperation(opcode = WordFactoryOpcode.FROM_SIGNED)
 149     public static <T extends SignedWord> T signed(int val) {
 150         return WordBoxFactory.box(val);
 151     }
 152 }