1 /*

     2  * Copyright (c) 2002, 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  *

    23  */

    24 

    25 package sun.jvm.hotspot.asm.sparc;

    26 

    27 import sun.jvm.hotspot.asm.*;

    28 

    29 class V9ReadDecoder extends InstructionDecoder

    30               implements V9InstructionDecoder {

    31     Instruction decode(int instruction, SPARCInstructionFactory factory) {

    32         SPARCV9InstructionFactory v9factory = (SPARCV9InstructionFactory) factory;

    33         Instruction instr = null;

    34         int specialRegNum = getSourceRegister1(instruction);

    35 

    36         // rs1 values 1, 7-14 are reserved - see page 214, A.44 Read State Register.

    37         if (specialRegNum == 1 || (specialRegNum > 6 && specialRegNum < 15)) {

    38             instr = v9factory.newIllegalInstruction(instruction);

    39         } else {

    40             int rdNum = getDestinationRegister(instruction);

    41             if (specialRegNum == 15) {

    42                 // may be stbar, member or illegal

    43                 if (rdNum == 0) {

    44                     boolean iBit = isIBitSet(instruction);

    45                     if (iBit) {

    46                         instr = v9factory.newV9MembarInstruction((instruction & MMASK_MASK) >>> MMASK_START_BIT,

    47                                                         (instruction & CMASK_MASK) >>> CMASK_START_BIT);

    48                     } else {

    49                         instr = v9factory.newStbarInstruction();

    50                     }

    51                 } else { // rd != 0 && rs1 == 15

    52                     instr = v9factory.newIllegalInstruction(instruction);

    53                 }

    54              } else {

    55                 int asrRegNum = -1;

    56                 if (specialRegNum > 15){

    57                     asrRegNum = specialRegNum;

    58                     specialRegNum = SPARCV9SpecialRegisters.ASR;

    59                 }

    60                 SPARCRegister rd = SPARCRegisters.getRegister(rdNum);

    61                 instr = v9factory.newV9ReadInstruction(specialRegNum, asrRegNum, rd);

    62              }

    63         }

    64         return instr;

    65     }

    66 }