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 abstract class V9RegisterBranchDecoder extends V9BranchDecoder {
  30     static int getDisp16(int instruction) {
  31         int offset = (DISP_16_LO_MASK & instruction)  |
  32            ((DISP_16_HI_MASK & instruction) >>> (DISP_16_HI_START_BIT - DISP_16_LO_NUMBITS));
  33 
  34         // sign extend and word align
  35         offset = extractSignedIntFromNBits(offset, 16);
  36         offset <<= 2;
  37 
  38         return offset;
  39     }
  40 
  41     String getConditionName(int conditionCode, boolean isAnnuled) {
  42         return null;
  43     }
  44 
  45     abstract String getRegisterConditionName(int rcond);
  46 
  47     public Instruction decode(int instruction, SPARCInstructionFactory factory) {
  48         SPARCV9InstructionFactory v9factory = (SPARCV9InstructionFactory) factory;
  49         int rcond = (BRANCH_RCOND_MASK & instruction) >>> BRANCH_RCOND_START_BIT;
  50         if (rcond == BRANCH_RCOND_RESERVED1 || rcond == BRANCH_RCOND_RESERVED2)
  51             return factory.newIllegalInstruction(instruction);
  52 
  53         SPARCRegister rs1 = SPARCRegisters.getRegister(getSourceRegister1(instruction));
  54         boolean predictTaken = getPredictTaken(instruction);
  55         boolean annuled = getAnnuledBit(instruction);
  56         PCRelativeAddress addr = new PCRelativeAddress(getDisp16(instruction));
  57         String name = getRegisterConditionName(rcond);
  58         return v9factory.newV9RegisterBranchInstruction(name, addr, annuled, rcond, rs1, predictTaken);
  59     }
  60 }