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Copy pathWordArray.java
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86 lines (77 loc) · 3.42 KB
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/*
* Copyright (c) 2007 Sun Microsystems, Inc. All rights reserved.
*
* Sun Microsystems, Inc. has intellectual property rights relating to technology embodied in the product
* that is described in this document. In particular, and without limitation, these intellectual property
* rights may include one or more of the U.S. patents listed at http://www.sun.com/patents and one or
* more additional patents or pending patent applications in the U.S. and in other countries.
*
* U.S. Government Rights - Commercial software. Government users are subject to the Sun
* Microsystems, Inc. standard license agreement and applicable provisions of the FAR and its
* supplements.
*
* Use is subject to license terms. Sun, Sun Microsystems, the Sun logo, Java and Solaris are trademarks or
* registered trademarks of Sun Microsystems, Inc. in the U.S. and other countries. All SPARC trademarks
* are used under license and are trademarks or registered trademarks of SPARC International, Inc. in the
* U.S. and other countries.
*
* UNIX is a registered trademark in the U.S. and other countries, exclusively licensed through X/Open
* Company, Ltd.
*/
package com.sun.max.unsafe;
import com.sun.max.annotate.*;
import com.sun.max.vm.object.*;
/**
* Why we never directly use any arrays of any subtype of 'Word':
*
* The byte codes aaload and aastore have no clue whether the array reference on the stack refers to a Word array or an
* Object array. As long as we are unable to or unsure whether we can discern the difference STATICALLY, we must not
* allow aaload and aastore to deal with either case dynamically.
*
* Compare this to the situation between byte arrays and boolean arrays addressed by baload and bastore! In those cases,
* we CAN differentiate between the respective array types DYNAMICALLY and cause no harm to the GC, because both types
* are primitive types.
*
* In case of Object and Word, one calls for a stack map entry and the other does not. Therefore, a dynamic distinction
* would require support for dynamic stack map changes. So far we are not willing to afford the price for that
* (runtime, implementation effort, complexity).
*
* Instead, always use WordArray.set() and WordArray.get() instead of [] when addressing word array elements.
*
* @author Bernd Mathiske
*/
public final class WordArray {
private WordArray() {
}
public static void fill(Word[] array, Word value) {
for (int i = 0; i < array.length; i++) {
uncheckedSet(array, i, value);
}
}
@INLINE
public static Word uncheckedGet(Word[] array, int index) {
return ArrayAccess.getWord(array, index);
}
@INLINE
public static Word get(Word[] array, int index) {
ArrayAccess.checkIndex(array, index);
return ArrayAccess.getWord(array, index);
}
@INLINE
public static void uncheckedSet(Word[] array, int index, Word value) {
ArrayAccess.setWord(array, index, value);
}
@INLINE
public static void set(Word[] array, int index, Word value) {
ArrayAccess.checkIndex(array, index);
ArrayAccess.setWord(array, index, value);
}
public static void copyAll(Word[] fromArray, Word[] toArray) {
if (fromArray.length > toArray.length) {
throw new ArrayIndexOutOfBoundsException();
}
for (int i = 0; i < fromArray.length; i++) {
uncheckedSet(toArray, i, uncheckedGet(fromArray, i));
}
}
}