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Bochs/bochs/cpu/mult32.cc
Kevin Lawton 402d02974d Moved the EFLAGS.RF check and clearing of inhibit_mask code 
in cpu.cc out of the main loop, and into the asynchronous
events handling.  I went through all the code paths, and
there doesn't seem to be any reason for that code to be
in the hot loop.

Added another accessor for getting instruction data, called
modC0().  A lot of instructions test whether the mod field
of mod-nnn-rm is 0xc0 or not, ie., it's a register operation
and not memory.  So I flag this in fetchdecode{,64}.cc.
This added on the order of 1% performance improvement for
a Win95 boot.

Macroized a few leftover calls to Write_RMV_virtual_xyz()
that didn't get modified in the x86-64 merge.  Really, they
just call the real function for now, but I want to have them
available to do direct writes with the guest2host TLB pointers.
2002-09-20 03:52:59 +00:00

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/////////////////////////////////////////////////////////////////////////
// $Id: mult32.cc,v 1.10 2002-09-20 03:52:58 kevinlawton Exp $
/////////////////////////////////////////////////////////////////////////
//
// Copyright (C) 2001 MandrakeSoft S.A.
//
// MandrakeSoft S.A.
// 43, rue d'Aboukir
// 75002 Paris - France
// http://www.linux-mandrake.com/
// http://www.mandrakesoft.com/
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2 of the License, or (at your option) any later version.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
#define NEED_CPU_REG_SHORTCUTS 1
#include "bochs.h"
#define LOG_THIS BX_CPU_THIS_PTR
#if BX_SUPPORT_X86_64==0
#define RAX EAX
#define RDX EDX
#endif
void
BX_CPU_C::MUL_EAXEd(bxInstruction_c *i)
{
Bit32u op1_32, op2_32, product_32h, product_32l;
Bit64u product_64;
Boolean temp_flag;
op1_32 = EAX;
/* op2 is a register or memory reference */
if (i->modC0()) {
op2_32 = BX_READ_32BIT_REG(i->rm());
}
else {
/* pointer, segment address pair */
read_virtual_dword(i->seg(), RMAddr(i), &op2_32);
}
product_64 = ((Bit64u) op1_32) * ((Bit64u) op2_32);
product_32l = (Bit32u) (product_64 & 0xFFFFFFFF);
product_32h = (Bit32u) (product_64 >> 32);
/* now write product back to destination */
RAX = product_32l;
RDX = product_32h;
/* set eflags:
* MUL affects the following flags: C,O
*/
temp_flag = (product_32h != 0);
SET_FLAGS_OxxxxC(temp_flag, temp_flag);
}
void
BX_CPU_C::IMUL_EAXEd(bxInstruction_c *i)
{
Bit32s op1_32, op2_32;
Bit64s product_64;
Bit32u product_32h, product_32l;
op1_32 = EAX;
/* op2 is a register or memory reference */
if (i->modC0()) {
op2_32 = BX_READ_32BIT_REG(i->rm());
}
else {
/* pointer, segment address pair */
read_virtual_dword(i->seg(), RMAddr(i), (Bit32u *) &op2_32);
}
product_64 = ((Bit64s) op1_32) * ((Bit64s) op2_32);
product_32l = (Bit32u) (product_64 & 0xFFFFFFFF);
product_32h = (Bit32u) (product_64 >> 32);
/* now write product back to destination */
RAX = product_32l;
RDX = product_32h;
/* set eflags:
* IMUL affects the following flags: C,O
* IMUL r/m16: condition for clearing CF & OF:
* EDX:EAX = sign-extend of EAX
*/
if ( (EDX==0xffffffff) && (EAX & 0x80000000) ) {
SET_FLAGS_OxxxxC(0, 0);
}
else if ( (EDX==0x00000000) && (EAX < 0x80000000) ) {
SET_FLAGS_OxxxxC(0, 0);
}
else {
SET_FLAGS_OxxxxC(1, 1);
}
}
void
BX_CPU_C::DIV_EAXEd(bxInstruction_c *i)
{
Bit32u op2_32, remainder_32, quotient_32l;
Bit64u op1_64, quotient_64;
op1_64 = (((Bit64u) EDX) << 32) + ((Bit64u) EAX);
/* op2 is a register or memory reference */
if (i->modC0()) {
op2_32 = BX_READ_32BIT_REG(i->rm());
}
else {
/* pointer, segment address pair */
read_virtual_dword(i->seg(), RMAddr(i), &op2_32);
}
if (op2_32 == 0) {
exception(BX_DE_EXCEPTION, 0, 0);
}
quotient_64 = op1_64 / op2_32;
remainder_32 = (Bit32u) (op1_64 % op2_32);
quotient_32l = (Bit32u) (quotient_64 & 0xFFFFFFFF);
if (quotient_64 != quotient_32l) {
exception(BX_DE_EXCEPTION, 0, 0);
}
/* set EFLAGS:
* DIV affects the following flags: O,S,Z,A,P,C are undefined
*/
/* now write quotient back to destination */
RAX = quotient_32l;
RDX = remainder_32;
}
void
BX_CPU_C::IDIV_EAXEd(bxInstruction_c *i)
{
Bit32s op2_32, remainder_32, quotient_32l;
Bit64s op1_64, quotient_64;
op1_64 = (((Bit64u) EDX) << 32) | ((Bit64u) EAX);
/* op2 is a register or memory reference */
if (i->modC0()) {
op2_32 = BX_READ_32BIT_REG(i->rm());
}
else {
/* pointer, segment address pair */
read_virtual_dword(i->seg(), RMAddr(i), (Bit32u *) &op2_32);
}
if (op2_32 == 0) {
exception(BX_DE_EXCEPTION, 0, 0);
}
quotient_64 = op1_64 / op2_32;
remainder_32 = (Bit32s) (op1_64 % op2_32);
quotient_32l = (Bit32s) (quotient_64 & 0xFFFFFFFF);
if (quotient_64 != quotient_32l) {
exception(BX_DE_EXCEPTION, 0, 0);
}
/* set EFLAGS:
* IDIV affects the following flags: O,S,Z,A,P,C are undefined
*/
/* now write quotient back to destination */
RAX = quotient_32l;
RDX = remainder_32;
}
void
BX_CPU_C::IMUL_GdEdId(bxInstruction_c *i)
{
#if BX_CPU_LEVEL < 2
BX_PANIC(("IMUL_GdEdId() unsupported on 8086!"));
#else
Bit32s op2_32, op3_32, product_32;
Bit64s product_64;
op3_32 = i->Id();
/* op2 is a register or memory reference */
if (i->modC0()) {
op2_32 = BX_READ_32BIT_REG(i->rm());
}
else {
/* pointer, segment address pair */
read_virtual_dword(i->seg(), RMAddr(i), (Bit32u *) &op2_32);
}
product_32 = op2_32 * op3_32;
product_64 = ((Bit64s) op2_32) * ((Bit64s) op3_32);
/* now write product back to destination */
BX_WRITE_32BIT_REGZ(i->nnn(), product_32);
/* set eflags:
* IMUL affects the following flags: C,O
* IMUL r16,r/m16,imm16: condition for clearing CF & OF:
* result exactly fits within r16
*/
if (product_64 == product_32) {
SET_FLAGS_OxxxxC(0, 0);
}
else {
SET_FLAGS_OxxxxC(1, 1);
}
#endif
}
void
BX_CPU_C::IMUL_GdEd(bxInstruction_c *i)
{
#if BX_CPU_LEVEL < 3
BX_PANIC(("IMUL_GvEv() unsupported on 8086!"));
#else
Bit32s op1_32, op2_32, product_32;
Bit64s product_64;
/* op2 is a register or memory reference */
if (i->modC0()) {
op2_32 = BX_READ_32BIT_REG(i->rm());
}
else {
/* pointer, segment address pair */
read_virtual_dword(i->seg(), RMAddr(i), (Bit32u *) &op2_32);
}
op1_32 = BX_READ_32BIT_REG(i->nnn());
product_32 = op1_32 * op2_32;
product_64 = ((Bit64s) op1_32) * ((Bit64s) op2_32);
/* now write product back to destination */
BX_WRITE_32BIT_REGZ(i->nnn(), product_32);
/* set eflags:
* IMUL affects the following flags: C,O
* IMUL r16,r/m16,imm16: condition for clearing CF & OF:
* result exactly fits within r16
*/
if (product_64 == product_32) {
SET_FLAGS_OxxxxC(0, 0);
}
else {
SET_FLAGS_OxxxxC(1, 1);
}
#endif
}
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