Bochs/bochs/cpu/mult16.cc
Stanislav Shwartsman cc694377b9 Standartization of Bochs instruction handlers.
Bochs instruction emulation handlers won't refer to direct fields of instructions like MODRM.NNN or MODRM.RM anymore.
Use generic source/destination indications like SRC1, SRC2 and DST.
All handlers are modified to support new notation. In addition fetchDecode module was modified to assign sources to instructions properly.

Immediate benefits:
- Removal of several duplicated handlers (FMA3 duplicated with FMA4 is a trivial example)
- Simpler to understand fetch-decode code

Future benefits:
- Integration of disassembler into Bochs CPU module, ability to disasm bx_instruction_c instance (planned)

Huge patch. Almost all source files wre modified.
2012-08-05 13:52:40 +00:00

172 lines
4.6 KiB
C++

/////////////////////////////////////////////////////////////////////////
// $Id$
/////////////////////////////////////////////////////////////////////////
//
// Copyright (C) 2001-2012 The Bochs Project
//
// 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., 51 Franklin St, Fifth Floor, Boston, MA B 02110-1301 USA
/////////////////////////////////////////////////////////////////////////
#define NEED_CPU_REG_SHORTCUTS 1
#include "bochs.h"
#include "cpu.h"
#define LOG_THIS BX_CPU_THIS_PTR
BX_INSF_TYPE BX_CPP_AttrRegparmN(1) BX_CPU_C::MUL_AXEwR(bxInstruction_c *i)
{
Bit16u op1_16 = AX;
Bit16u op2_16 = BX_READ_16BIT_REG(i->src());
Bit32u product_32 = ((Bit32u) op1_16) * ((Bit32u) op2_16);
Bit16u product_16l = (product_32 & 0xFFFF);
Bit16u product_16h = product_32 >> 16;
/* now write product back to destination */
AX = product_16l;
DX = product_16h;
/* set EFLAGS */
SET_FLAGS_OSZAPC_LOGIC_16(product_16l);
if(product_16h != 0)
{
ASSERT_FLAGS_OxxxxC();
}
BX_NEXT_INSTR(i);
}
BX_INSF_TYPE BX_CPP_AttrRegparmN(1) BX_CPU_C::IMUL_AXEwR(bxInstruction_c *i)
{
Bit16s op1_16 = AX;
Bit16s op2_16 = BX_READ_16BIT_REG(i->src());
Bit32s product_32 = ((Bit32s) op1_16) * ((Bit32s) op2_16);
Bit16u product_16l = (product_32 & 0xFFFF);
Bit16u product_16h = product_32 >> 16;
/* now write product back to destination */
AX = product_16l;
DX = product_16h;
/* set eflags:
* IMUL r/m16: condition for clearing CF & OF:
* DX:AX = sign-extend of AX
*/
SET_FLAGS_OSZAPC_LOGIC_16(product_16l);
if(product_32 != (Bit16s)product_32)
{
ASSERT_FLAGS_OxxxxC();
}
BX_NEXT_INSTR(i);
}
BX_INSF_TYPE BX_CPP_AttrRegparmN(1) BX_CPU_C::DIV_AXEwR(bxInstruction_c *i)
{
Bit16u op2_16 = BX_READ_16BIT_REG(i->src());
if (op2_16 == 0)
exception(BX_DE_EXCEPTION, 0);
Bit32u op1_32 = (((Bit32u) DX) << 16) | ((Bit32u) AX);
Bit32u quotient_32 = op1_32 / op2_16;
Bit16u remainder_16 = op1_32 % op2_16;
Bit16u quotient_16l = quotient_32 & 0xFFFF;
if (quotient_32 != quotient_16l)
exception(BX_DE_EXCEPTION, 0);
/* now write quotient back to destination */
AX = quotient_16l;
DX = remainder_16;
BX_NEXT_INSTR(i);
}
BX_INSF_TYPE BX_CPP_AttrRegparmN(1) BX_CPU_C::IDIV_AXEwR(bxInstruction_c *i)
{
Bit32s op1_32 = ((((Bit32u) DX) << 16) | ((Bit32u) AX));
/* check MIN_INT case */
if (op1_32 == ((Bit32s)0x80000000))
exception(BX_DE_EXCEPTION, 0);
Bit16s op2_16 = BX_READ_16BIT_REG(i->src());
if (op2_16 == 0)
exception(BX_DE_EXCEPTION, 0);
Bit32s quotient_32 = op1_32 / op2_16;
Bit16s remainder_16 = op1_32 % op2_16;
Bit16s quotient_16l = quotient_32 & 0xFFFF;
if (quotient_32 != quotient_16l)
exception(BX_DE_EXCEPTION, 0);
/* now write quotient back to destination */
AX = quotient_16l;
DX = remainder_16;
BX_NEXT_INSTR(i);
}
BX_INSF_TYPE BX_CPP_AttrRegparmN(1) BX_CPU_C::IMUL_GwEwIwR(bxInstruction_c *i)
{
Bit16s op2_16 = BX_READ_16BIT_REG(i->src());
Bit16s op3_16 = i->Iw();
Bit32s product_32 = op2_16 * op3_16;
Bit16u product_16 = (product_32 & 0xFFFF);
/* now write product back to destination */
BX_WRITE_16BIT_REG(i->dst(), product_16);
/* set eflags:
* IMUL r16,r/m16,imm16: condition for clearing CF & OF:
* result exactly fits within r16
*/
SET_FLAGS_OSZAPC_LOGIC_16(product_16);
if(product_32 != (Bit16s) product_32)
{
ASSERT_FLAGS_OxxxxC();
}
BX_NEXT_INSTR(i);
}
BX_INSF_TYPE BX_CPP_AttrRegparmN(1) BX_CPU_C::IMUL_GwEwR(bxInstruction_c *i)
{
Bit16s op1_16 = BX_READ_16BIT_REG(i->dst());
Bit16s op2_16 = BX_READ_16BIT_REG(i->src());
Bit32s product_32 = op1_16 * op2_16;
Bit16u product_16 = (product_32 & 0xFFFF);
/* now write product back to destination */
BX_WRITE_16BIT_REG(i->dst(), product_16);
/* set eflags:
* IMUL r16,r/m16: condition for clearing CF & OF:
* result exactly fits within r16
*/
SET_FLAGS_OSZAPC_LOGIC_16(product_16);
if(product_32 != (Bit16s) product_32)
{
ASSERT_FLAGS_OxxxxC();
}
BX_NEXT_INSTR(i);
}