/*
 * Copyright (c) 2002, 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.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores,
 * CA 94065 USA or visit www.oracle.com if you need additional information or
 * have any questions.
 *
 */

package sun.jvm.hotspot.asm.sparc;

import sun.jvm.hotspot.asm.*;

class V9WriteDecoder extends InstructionDecoder
              implements V9InstructionDecoder {
    Instruction decode(int instruction, SPARCInstructionFactory factory) {
        SPARCV9InstructionFactory v9factory = (SPARCV9InstructionFactory) factory;
        Instruction instr = null;
        int specialRegNum = getDestinationRegister(instruction);

        // rd values 1, 4,5 7-14 are reserved - see page 244, A.63 Write State Register.
        if (specialRegNum == 1 || specialRegNum == 4 || specialRegNum == 5
            || (specialRegNum > 6 && specialRegNum < 15)) {
            instr = v9factory.newIllegalInstruction(instruction);
        } else {
            int rs1Num = getSourceRegister1(instruction);
            if (specialRegNum == 15) {
                if (isIBitSet(instruction) && rs1Num == 0) {
                    instr = v9factory.newV9SirInstruction();
                } else {
                    instr = v9factory.newIllegalInstruction(instruction);
                }
            } else {
                int asrRegNum = -1;
                if (specialRegNum > 15) {
                    asrRegNum = specialRegNum;
                    specialRegNum = SPARCV9SpecialRegisters.ASR;
                }
                SPARCRegister rs1 = SPARCRegisters.getRegister(rs1Num);
                instr = v9factory.newV9WriteInstruction(specialRegNum, asrRegNum, rs1, getOperand2(instruction));
            }
        }

        return instr;
    }
}