/*
* Copyright (c) 2007, 2011, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
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*/
package com.sun.max.asm.gen.risc.bitRange;
/**
* A bit range that has its most significant bit on the left and its least significant bit on the right.
*/
public class DescendingBitRange extends SimpleBitRange {
public DescendingBitRange(int firstIndex, int lastIndex) {
super(firstIndex, lastIndex);
if (firstIndex < lastIndex) {
throw new IllegalArgumentException("bit ranges are specified from left to right, and descending notation starts at 31 and goes down to 0");
}
}
@Override
public DescendingBitRange move(boolean left, int bits) {
if (left) {
return new DescendingBitRange(firstBitIndex + bits, lastBitIndex + bits);
}
return new DescendingBitRange(firstBitIndex - bits, lastBitIndex - bits);
}
@Override
public int numberOfLessSignificantBits() {
return lastBitIndex;
}
@Override
public int width() {
return (firstBitIndex - lastBitIndex) + 1;
}
}