1 /*
   2  * Copyright 2002 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
  20  * CA 95054 USA or visit www.sun.com if you need additional information or
  21  * have any questions.
  22  *
  23  */
  24 
  25 package sun.jvm.hotspot.asm.sparc;
  26 
  27 import sun.jvm.hotspot.asm.*;
  28 
  29 class V9WriteDecoder extends InstructionDecoder
  30               implements V9InstructionDecoder {
  31     Instruction decode(int instruction, SPARCInstructionFactory factory) {
  32         SPARCV9InstructionFactory v9factory = (SPARCV9InstructionFactory) factory;
  33         Instruction instr = null;
  34         int specialRegNum = getDestinationRegister(instruction);
  35 
  36         // rd values 1, 4,5 7-14 are reserved - see page 244, A.63 Write State Register.
  37         if (specialRegNum == 1 || specialRegNum == 4 || specialRegNum == 5
  38             || (specialRegNum > 6 && specialRegNum < 15)) {
  39             instr = v9factory.newIllegalInstruction(instruction);
  40         } else {
  41             int rs1Num = getSourceRegister1(instruction);
  42             if (specialRegNum == 15) {
  43                 if (isIBitSet(instruction) && rs1Num == 0) {
  44                     instr = v9factory.newV9SirInstruction();
  45                 } else {
  46                     instr = v9factory.newIllegalInstruction(instruction);
  47                 }
  48             } else {
  49                 int asrRegNum = -1;
  50                 if (specialRegNum > 15) {
  51                     asrRegNum = specialRegNum;
  52                     specialRegNum = SPARCV9SpecialRegisters.ASR;
  53                 }
  54                 SPARCRegister rs1 = SPARCRegisters.getRegister(rs1Num);
  55                 instr = v9factory.newV9WriteInstruction(specialRegNum, asrRegNum, rs1, getOperand2(instruction));
  56             }
  57         }
  58 
  59         return instr;
  60     }
  61 }