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/*
* Copyright (c) 2007 The Hewlett-Packard Development Company
* All rights reserved.
*
* The license below extends only to copyright in the software and shall
* not be construed as granting a license to any other intellectual
* property including but not limited to intellectual property relating
* to a hardware implementation of the functionality of the software
* licensed hereunder. You may use the software subject to the license
* terms below provided that you ensure that this notice is replicated
* unmodified and in its entirety in all distributions of the software,
* modified or unmodified, in source code or in binary form.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met: 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 holders nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* 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 "arch/x86/emulenv.hh"
#include <cassert>
#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 decoder.
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) {
unsigned rm = machInst.modRM.rm;
if (rm <= 3) {
scale = 1;
if (rm < 2) {
base = INTREG_RBX;
} else {
base = INTREG_RBP;
}
index = (rm % 2) ? INTREG_RDI : INTREG_RSI;
} else {
scale = 0;
switch (rm) {
case 4:
base = INTREG_RSI;
break;
case 5:
base = INTREG_RDI;
break;
case 6:
base = INTREG_RBP;
break;
case 7:
base = INTREG_RBX;
break;
}
}
} 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) || machInst.dispSize) {
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;
}
}
void EmulEnv::setSeg(const ExtMachInst & machInst)
{
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);
}
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