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/*
* Copyright (c) 2007 The Hewlett-Packard Development Company
* All rights reserved.
*
* Redistribution and use of this software in source and binary forms,
* with or without modification, are permitted provided that the
* following conditions are met:
*
* The software must be used only for Non-Commercial Use which means any
* use which is NOT directed to receiving any direct monetary
* compensation for, or commercial advantage from such use. Illustrative
* examples of non-commercial use are academic research, personal study,
* teaching, education and corporate research & development.
* Illustrative examples of commercial use are distributing products for
* commercial advantage and providing services using the software for
* commercial advantage.
*
* If you wish to use this software or functionality therein that may be
* covered by patents for commercial use, please contact:
* Director of Intellectual Property Licensing
* Office of Strategy and Technology
* Hewlett-Packard Company
* 1501 Page Mill Road
* Palo Alto, California 94304
*
* Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer. Redistributions
* in binary form must reproduce the above copyright notice, this list of
* conditions and the following disclaimer in the documentation and/or
* other materials provided with the distribution. Neither the name of
* the COPYRIGHT HOLDER(s), HEWLETT-PACKARD COMPANY, nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission. No right of
* sublicense is granted herewith. Derivatives of the software and
* output created using the software may be prepared, but only for
* Non-Commercial Uses. Derivatives of the software may be shared with
* others provided: (i) the others agree to abide by the list of
* conditions herein which includes the Non-Commercial Use restrictions;
* and (ii) such Derivatives of the software include the above copyright
* notice to acknowledge the contribution from this software where
* applicable, this list of conditions and the disclaimer below.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* Authors: Gabe Black
*/
#include <cassert>
#include "arch/x86/emulenv.hh"
#include "base/misc.hh"
using namespace X86ISA;
void EmulEnv::doModRM(const ExtMachInst & machInst)
{
assert(machInst.modRM.mod != 3);
//Use the SIB byte for addressing if the modrm byte calls for it.
if (machInst.modRM.rm == 4 && machInst.addrSize != 2) {
scale = 1 << machInst.sib.scale;
index = machInst.sib.index | (machInst.rex.x << 3);
base = machInst.sib.base | (machInst.rex.b << 3);
//In this special case, we don't use a base. The displacement also
//changes, but that's managed by the predecoder.
if (machInst.sib.base == INTREG_RBP && machInst.modRM.mod == 0)
base = NUM_INTREGS;
//In -this- special case, we don't use an index.
if (index == INTREG_RSP)
index = NUM_INTREGS;
} else {
if (machInst.addrSize == 2) {
warn("I'm not really using 16 bit MODRM like I'm supposed to!\n");
} else {
scale = 0;
base = machInst.modRM.rm | (machInst.rex.b << 3);
if (machInst.modRM.mod == 0 && machInst.modRM.rm == 5) {
//Since we need to use a different encoding of this
//instruction anyway, just ignore the base in those cases
base = NUM_INTREGS;
}
}
}
//Figure out what segment to use. This won't be entirely accurate since
//the presence of a displacement is supposed to make the instruction
//default to the data segment.
if ((base != INTREG_RBP && base != INTREG_RSP) ||
0/*Has an immediate offset*/) {
seg = SEGMENT_REG_DS;
//Handle any segment override that might have been in the instruction
int segFromInst = machInst.legacy.seg;
if (segFromInst)
seg = (SegmentRegIndex)(segFromInst - 1);
} else {
seg = SEGMENT_REG_SS;
}
}
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