emulenv.cc revision 4863:b6dacc9a39ff
1/* 2 * Copyright (c) 2007 The Hewlett-Packard Development Company 3 * All rights reserved. 4 * 5 * Redistribution and use of this software in source and binary forms, 6 * with or without modification, are permitted provided that the 7 * following conditions are met: 8 * 9 * The software must be used only for Non-Commercial Use which means any 10 * use which is NOT directed to receiving any direct monetary 11 * compensation for, or commercial advantage from such use. Illustrative 12 * examples of non-commercial use are academic research, personal study, 13 * teaching, education and corporate research & development. 14 * Illustrative examples of commercial use are distributing products for 15 * commercial advantage and providing services using the software for 16 * commercial advantage. 17 * 18 * If you wish to use this software or functionality therein that may be 19 * covered by patents for commercial use, please contact: 20 * Director of Intellectual Property Licensing 21 * Office of Strategy and Technology 22 * Hewlett-Packard Company 23 * 1501 Page Mill Road 24 * Palo Alto, California 94304 25 * 26 * Redistributions of source code must retain the above copyright notice, 27 * this list of conditions and the following disclaimer. Redistributions 28 * in binary form must reproduce the above copyright notice, this list of 29 * conditions and the following disclaimer in the documentation and/or 30 * other materials provided with the distribution. Neither the name of 31 * the COPYRIGHT HOLDER(s), HEWLETT-PACKARD COMPANY, nor the names of its 32 * contributors may be used to endorse or promote products derived from 33 * this software without specific prior written permission. No right of 34 * sublicense is granted herewith. Derivatives of the software and 35 * output created using the software may be prepared, but only for 36 * Non-Commercial Uses. Derivatives of the software may be shared with 37 * others provided: (i) the others agree to abide by the list of 38 * conditions herein which includes the Non-Commercial Use restrictions; 39 * and (ii) such Derivatives of the software include the above copyright 40 * notice to acknowledge the contribution from this software where 41 * applicable, this list of conditions and the disclaimer below. 42 * 43 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 44 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 45 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 46 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 47 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 48 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 49 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 50 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 51 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 52 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 53 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 54 * 55 * Authors: Gabe Black 56 */ 57 58#include "arch/x86/emulenv.hh" 59#include "base/misc.hh" 60 61using namespace X86ISA; 62 63void EmulEnv::doModRM(const ExtMachInst & machInst) 64{ 65 assert(machInst.modRM.mod != 3); 66 //Use the SIB byte for addressing if the modrm byte calls for it. 67 if (machInst.modRM.rm == 4 && machInst.addrSize != 2) { 68 scale = 1 << machInst.sib.scale; 69 index = machInst.sib.index | (machInst.rex.x << 3); 70 base = machInst.sib.base | (machInst.rex.b << 3); 71 //In this special case, we don't use a base. The displacement also 72 //changes, but that's managed by the predecoder. 73 if (machInst.sib.base == INTREG_RBP && machInst.modRM.mod == 0) 74 base = NUM_INTREGS; 75 //In -this- special case, we don't use an index. 76 if (index == INTREG_RSP) 77 index = NUM_INTREGS; 78 } else { 79 if (machInst.addrSize == 2) { 80 warn("I'm not really using 16 bit MODRM like I'm supposed to!\n"); 81 } else { 82 scale = 0; 83 base = machInst.modRM.rm | (machInst.rex.b << 3); 84 if (machInst.modRM.mod == 0 && machInst.modRM.rm == 5) { 85 //Since we need to use a different encoding of this 86 //instruction anyway, just ignore the base in those cases 87 base = NUM_INTREGS; 88 } 89 } 90 } 91 //Figure out what segment to use. This won't be entirely accurate since 92 //the presence of a displacement is supposed to make the instruction 93 //default to the data segment. 94 if (base != INTREG_RBP && base != INTREG_RSP || 95 0/*Has an immediate offset*/) { 96 seg = SEGMENT_REG_DS; 97 //Handle any segment override that might have been in the instruction 98 int segFromInst = machInst.legacy.seg; 99 if (segFromInst) 100 seg = (SegmentRegIndex)(segFromInst - 1); 101 } else { 102 seg = SEGMENT_REG_SS; 103 } 104} 105 106