11689SN/A/* 21689SN/A * Copyright (c) 2004-2005 The Regents of The University of Michigan 31689SN/A * All rights reserved. 41689SN/A * 51689SN/A * Redistribution and use in source and binary forms, with or without 61689SN/A * modification, are permitted provided that the following conditions are 71689SN/A * met: redistributions of source code must retain the above copyright 81689SN/A * notice, this list of conditions and the following disclaimer; 91689SN/A * redistributions in binary form must reproduce the above copyright 101689SN/A * notice, this list of conditions and the following disclaimer in the 111689SN/A * documentation and/or other materials provided with the distribution; 121689SN/A * neither the name of the copyright holders nor the names of its 131689SN/A * contributors may be used to endorse or promote products derived from 141689SN/A * this software without specific prior written permission. 151689SN/A * 161689SN/A * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 171689SN/A * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 181689SN/A * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 191689SN/A * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 201689SN/A * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 211689SN/A * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 221689SN/A * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 231689SN/A * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 241689SN/A * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 251689SN/A * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 261689SN/A * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 272665SN/A * 282665SN/A * Authors: Kevin Lim 291689SN/A */ 301689SN/A 319480Snilay@cs.wisc.edu#ifndef __CPU_PRED_RAS_HH__ 329480Snilay@cs.wisc.edu#define __CPU_PRED_RAS_HH__ 331062SN/A 346216SN/A#include <vector> 356216SN/A 367720Sgblack@eecs.umich.edu#include "arch/types.hh" 376214SN/A#include "base/types.hh" 387720Sgblack@eecs.umich.edu#include "config/the_isa.hh" 391062SN/A 402292SN/A/** Return address stack class, implements a simple RAS. */ 411062SN/Aclass ReturnAddrStack 421062SN/A{ 431062SN/A public: 442292SN/A /** Creates a return address stack, but init() must be called prior to 452292SN/A * use. 462292SN/A */ 472292SN/A ReturnAddrStack() {} 481062SN/A 492292SN/A /** Initializes RAS with a specified number of entries. 502292SN/A * @param numEntries Number of entries in the RAS. 512292SN/A */ 522292SN/A void init(unsigned numEntries); 532292SN/A 542307SN/A void reset(); 552307SN/A 562292SN/A /** Returns the top address on the RAS. */ 577720Sgblack@eecs.umich.edu TheISA::PCState top() 581062SN/A { return addrStack[tos]; } 591062SN/A 602292SN/A /** Returns the index of the top of the RAS. */ 611062SN/A unsigned topIdx() 621062SN/A { return tos; } 631062SN/A 642292SN/A /** Pushes an address onto the RAS. */ 657720Sgblack@eecs.umich.edu void push(const TheISA::PCState &return_addr); 661062SN/A 672292SN/A /** Pops the top address from the RAS. */ 681062SN/A void pop(); 691062SN/A 702292SN/A /** Changes index to the top of the RAS, and replaces the top address with 712292SN/A * a new target. 722292SN/A * @param top_entry_idx The index of the RAS that will now be the top. 737720Sgblack@eecs.umich.edu * @param restored The new target address of the new top of the RAS. 742292SN/A */ 757720Sgblack@eecs.umich.edu void restore(unsigned top_entry_idx, const TheISA::PCState &restored); 761062SN/A 775865SN/A bool empty() { return usedEntries == 0; } 785865SN/A 795865SN/A bool full() { return usedEntries == numEntries; } 801062SN/A private: 812292SN/A /** Increments the top of stack index. */ 821062SN/A inline void incrTos() 831684SN/A { if (++tos == numEntries) tos = 0; } 841062SN/A 852292SN/A /** Decrements the top of stack index. */ 861062SN/A inline void decrTos() 871062SN/A { tos = (tos == 0 ? numEntries - 1 : tos - 1); } 881062SN/A 892292SN/A /** The RAS itself. */ 907720Sgblack@eecs.umich.edu std::vector<TheISA::PCState> addrStack; 911062SN/A 922292SN/A /** The number of entries in the RAS. */ 931062SN/A unsigned numEntries; 941062SN/A 952292SN/A /** The number of used entries in the RAS. */ 961062SN/A unsigned usedEntries; 971062SN/A 982292SN/A /** The top of stack index. */ 991062SN/A unsigned tos; 1001062SN/A}; 1011062SN/A 1029480Snilay@cs.wisc.edu#endif // __CPU_PRED_RAS_HH__ 103