btb.hh revision 2665
1/* 2 * Copyright (c) 2004-2005 The Regents of The University of Michigan 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions are 7 * met: redistributions of source code must retain the above copyright 8 * notice, this list of conditions and the following disclaimer; 9 * redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution; 12 * neither the name of the copyright holders nor the names of its 13 * contributors may be used to endorse or promote products derived from 14 * this software without specific prior written permission. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 17 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 18 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 19 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 20 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 21 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 22 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 26 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 * 28 * Authors: Kevin Lim 29 */ 30 31#ifndef __CPU_O3_CPU_BTB_HH__ 32#define __CPU_O3_CPU_BTB_HH__ 33 34// For Addr type. 35#include "arch/isa_traits.hh" 36 37class DefaultBTB 38{ 39 private: 40 struct BTBEntry 41 { 42 BTBEntry() 43 : tag(0), target(0), valid(false) 44 { 45 } 46 47 Addr tag; 48 Addr target; 49 bool valid; 50 }; 51 52 public: 53 DefaultBTB(unsigned numEntries, unsigned tagBits, 54 unsigned instShiftAmt); 55 56 Addr lookup(const Addr &inst_PC); 57 58 bool valid(const Addr &inst_PC); 59 60 void update(const Addr &inst_PC, const Addr &target_PC); 61 62 private: 63 inline unsigned getIndex(const Addr &inst_PC); 64 65 inline Addr getTag(const Addr &inst_PC); 66 67 BTBEntry *btb; 68 69 unsigned numEntries; 70 71 unsigned idxMask; 72 73 unsigned tagBits; 74 75 unsigned tagMask; 76 77 unsigned instShiftAmt; 78 79 unsigned tagShiftAmt; 80}; 81 82#endif // __CPU_O3_CPU_BTB_HH__ 83