emulenv.cc revision 9023
1/* 2 * Copyright (c) 2007 The Hewlett-Packard Development Company 3 * All rights reserved. 4 * 5 * The license below extends only to copyright in the software and shall 6 * not be construed as granting a license to any other intellectual 7 * property including but not limited to intellectual property relating 8 * to a hardware implementation of the functionality of the software 9 * licensed hereunder. You may use the software subject to the license 10 * terms below provided that you ensure that this notice is replicated 11 * unmodified and in its entirety in all distributions of the software, 12 * modified or unmodified, in source code or in binary form. 13 * 14 * Redistribution and use in source and binary forms, with or without 15 * modification, are permitted provided that the following conditions are 16 * met: redistributions of source code must retain the above copyright 17 * notice, this list of conditions and the following disclaimer; 18 * redistributions in binary form must reproduce the above copyright 19 * notice, this list of conditions and the following disclaimer in the 20 * documentation and/or other materials provided with the distribution; 21 * neither the name of the copyright holders nor the names of its 22 * contributors may be used to endorse or promote products derived from 23 * this software without specific prior written permission. 24 * 25 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 26 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 27 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 28 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 29 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 30 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 31 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 32 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 33 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 34 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 35 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 36 * 37 * Authors: Gabe Black 38 */ 39 40#include <cassert> 41 42#include "arch/x86/emulenv.hh" 43#include "base/misc.hh" 44 45using namespace X86ISA; 46 47void EmulEnv::doModRM(const ExtMachInst & machInst) 48{ 49 assert(machInst.modRM.mod != 3); 50 //Use the SIB byte for addressing if the modrm byte calls for it. 51 if (machInst.modRM.rm == 4 && machInst.addrSize != 2) { 52 scale = 1 << machInst.sib.scale; 53 index = machInst.sib.index | (machInst.rex.x << 3); 54 base = machInst.sib.base | (machInst.rex.b << 3); 55 //In this special case, we don't use a base. The displacement also 56 //changes, but that's managed by the decoder. 57 if (machInst.sib.base == INTREG_RBP && machInst.modRM.mod == 0) 58 base = NUM_INTREGS; 59 //In -this- special case, we don't use an index. 60 if (index == INTREG_RSP) 61 index = NUM_INTREGS; 62 } else { 63 if (machInst.addrSize == 2) { 64 unsigned rm = machInst.modRM.rm; 65 if (rm <= 3) { 66 scale = 1; 67 if (rm < 2) { 68 base = INTREG_RBX; 69 } else { 70 base = INTREG_RBP; 71 } 72 index = (rm % 2) ? INTREG_RDI : INTREG_RSI; 73 } else { 74 scale = 0; 75 switch (rm) { 76 case 4: 77 base = INTREG_RSI; 78 break; 79 case 5: 80 base = INTREG_RDI; 81 break; 82 case 6: 83 base = INTREG_RBP; 84 break; 85 case 7: 86 base = INTREG_RBX; 87 break; 88 } 89 } 90 } else { 91 scale = 0; 92 base = machInst.modRM.rm | (machInst.rex.b << 3); 93 if (machInst.modRM.mod == 0 && machInst.modRM.rm == 5) { 94 //Since we need to use a different encoding of this 95 //instruction anyway, just ignore the base in those cases 96 base = NUM_INTREGS; 97 } 98 } 99 } 100 //Figure out what segment to use. This won't be entirely accurate since 101 //the presence of a displacement is supposed to make the instruction 102 //default to the data segment. 103 if ((base != INTREG_RBP && base != INTREG_RSP) || machInst.dispSize) { 104 seg = SEGMENT_REG_DS; 105 //Handle any segment override that might have been in the instruction 106 int segFromInst = machInst.legacy.seg; 107 if (segFromInst) 108 seg = (SegmentRegIndex)(segFromInst - 1); 109 } else { 110 seg = SEGMENT_REG_SS; 111 } 112} 113 114void EmulEnv::setSeg(const ExtMachInst & machInst) 115{ 116 seg = SEGMENT_REG_DS; 117 //Handle any segment override that might have been in the instruction 118 int segFromInst = machInst.legacy.seg; 119 if (segFromInst) 120 seg = (SegmentRegIndex)(segFromInst - 1); 121} 122