/////////////////////////////////////////////////////////////////////////
// $Id: arith8.cc,v 1.39 2006-03-26 18:58:00 sshwarts 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"
#include "cpu.h"
#define LOG_THIS BX_CPU_THIS_PTR


void BX_CPU_C::ADD_EbGb(bxInstruction_c *i)
{
  Bit8u op2, op1, sum;

  op2 = BX_READ_8BIT_REGx(i->nnn(),i->extend8bitL());

  if (i->modC0()) {
    op1 = BX_READ_8BIT_REGx(i->rm(),i->extend8bitL());
    sum = op1 + op2;
    BX_WRITE_8BIT_REGx(i->rm(), i->extend8bitL(), sum);
  }
  else {
    read_RMW_virtual_byte(i->seg(), RMAddr(i), &op1);
    sum = op1 + op2;
    write_RMW_virtual_byte(sum);
  }

  SET_FLAGS_OSZAPC_8(op1, op2, sum, BX_INSTR_ADD8);
}

void BX_CPU_C::ADD_GbEb(bxInstruction_c *i)
{
  Bit8u op1, op2, sum;

  op1 = BX_READ_8BIT_REGx(i->nnn(),i->extend8bitL());

  if (i->modC0()) {
    op2 = BX_READ_8BIT_REGx(i->rm(),i->extend8bitL());
    sum = op1 + op2;
  }
  else {
    read_virtual_byte(i->seg(), RMAddr(i), &op2);
    sum = op1 + op2;
  }

  BX_WRITE_8BIT_REGx(i->nnn(), i->extend8bitL(), sum);

  SET_FLAGS_OSZAPC_8(op1, op2, sum, BX_INSTR_ADD8);
}

void BX_CPU_C::ADD_ALIb(bxInstruction_c *i)
{
  Bit8u op1, op2, sum;

  op1 = AL;
  op2 = i->Ib();
  sum = op1 + op2;
  AL = sum;

  SET_FLAGS_OSZAPC_8(op1, op2, sum, BX_INSTR_ADD8);
}

void BX_CPU_C::ADC_EbGb(bxInstruction_c *i)
{
  Bit8u op2, op1, sum;
  bx_bool temp_CF = getB_CF();

  op2 = BX_READ_8BIT_REGx(i->nnn(),i->extend8bitL());

  if (i->modC0()) {
    op1 = BX_READ_8BIT_REGx(i->rm(),i->extend8bitL());
    sum = op1 + op2 + temp_CF;
    BX_WRITE_8BIT_REGx(i->rm(), i->extend8bitL(), sum);
  }
  else {
    read_RMW_virtual_byte(i->seg(), RMAddr(i), &op1);
    sum = op1 + op2 + temp_CF;
    write_RMW_virtual_byte(sum);
  }

  SET_FLAGS_OSZAPC_8(op1, op2, sum, BX_INSTR_ADD_ADC8(temp_CF));
}

void BX_CPU_C::ADC_GbEb(bxInstruction_c *i)
{
  Bit8u op1, op2, sum;
  bx_bool temp_CF = getB_CF();

  op1 = BX_READ_8BIT_REGx(i->nnn(),i->extend8bitL());

  if (i->modC0()) {
    op2 = BX_READ_8BIT_REGx(i->rm(),i->extend8bitL());
  }
  else {
    read_virtual_byte(i->seg(), RMAddr(i), &op2);
  }

  sum = op1 + op2 + temp_CF;

  SET_FLAGS_OSZAPC_8(op1, op2, sum, BX_INSTR_ADD_ADC8(temp_CF));

  BX_WRITE_8BIT_REGx(i->nnn(), i->extend8bitL(), sum);
}

void BX_CPU_C::ADC_ALIb(bxInstruction_c *i)
{
  Bit8u op1, op2, sum;
  bx_bool temp_CF = getB_CF();

  op1 = AL;
  op2 = i->Ib();
  sum = op1 + op2 + temp_CF;
  AL = sum;

  SET_FLAGS_OSZAPC_8(op1, op2, sum, BX_INSTR_ADD_ADC8(temp_CF));
}

void BX_CPU_C::SBB_EbGb(bxInstruction_c *i)
{
  Bit8u op2_8, op1_8, diff_8;
  bx_bool temp_CF = getB_CF();

  op2_8 = BX_READ_8BIT_REGx(i->nnn(),i->extend8bitL());

  if (i->modC0()) {
    op1_8 = BX_READ_8BIT_REGx(i->rm(),i->extend8bitL());
    diff_8 = op1_8 - (op2_8 + temp_CF);
    BX_WRITE_8BIT_REGx(i->rm(), i->extend8bitL(), diff_8);
  }
  else {
    read_RMW_virtual_byte(i->seg(), RMAddr(i), &op1_8);
    diff_8 = op1_8 - (op2_8 + temp_CF);
    write_RMW_virtual_byte(diff_8);
  }

  SET_FLAGS_OSZAPC_8(op1_8, op2_8, diff_8, BX_INSTR_SUB_SBB8(temp_CF));
}

void BX_CPU_C::SBB_GbEb(bxInstruction_c *i)
{
  Bit8u op1_8, op2_8, diff_8;
  bx_bool temp_CF = getB_CF();

  op1_8 = BX_READ_8BIT_REGx(i->nnn(),i->extend8bitL());

  if (i->modC0()) {
    op2_8 = BX_READ_8BIT_REGx(i->rm(),i->extend8bitL());
  }
  else {
    read_virtual_byte(i->seg(), RMAddr(i), &op2_8);
  }

  diff_8 = op1_8 - (op2_8 + temp_CF);

  BX_WRITE_8BIT_REGx(i->nnn(), i->extend8bitL(), diff_8);

  SET_FLAGS_OSZAPC_8(op1_8, op2_8, diff_8, BX_INSTR_SUB_SBB8(temp_CF));
}

void BX_CPU_C::SBB_ALIb(bxInstruction_c *i)
{
  Bit8u op1_8, op2_8, diff_8;
  bx_bool temp_CF = getB_CF();

  op1_8 = AL;
  op2_8 = i->Ib();
  diff_8 = op1_8 - (op2_8 + temp_CF);
  AL = diff_8;

  SET_FLAGS_OSZAPC_8(op1_8, op2_8, diff_8, BX_INSTR_SUB_SBB8(temp_CF));
}

void BX_CPU_C::SBB_EbIb(bxInstruction_c *i)
{
  Bit8u op2_8, op1_8, diff_8;
  bx_bool temp_CF = getB_CF();

  op2_8 = i->Ib();

  if (i->modC0()) {
    op1_8 = BX_READ_8BIT_REGx(i->rm(),i->extend8bitL());
    diff_8 = op1_8 - (op2_8 + temp_CF);
    BX_WRITE_8BIT_REGx(i->rm(), i->extend8bitL(), diff_8);
  }
  else {
    read_RMW_virtual_byte(i->seg(), RMAddr(i), &op1_8);
    diff_8 = op1_8 - (op2_8 + temp_CF);
    write_RMW_virtual_byte(diff_8);
  }

  SET_FLAGS_OSZAPC_8(op1_8, op2_8, diff_8, BX_INSTR_SUB_SBB8(temp_CF));
}

void BX_CPU_C::SUB_EbGb(bxInstruction_c *i)
{
  Bit8u op2_8, op1_8, diff_8;

  op2_8 = BX_READ_8BIT_REGx(i->nnn(),i->extend8bitL());

  if (i->modC0()) {
    op1_8 = BX_READ_8BIT_REGx(i->rm(),i->extend8bitL());
    diff_8 = op1_8 - op2_8;
    BX_WRITE_8BIT_REGx(i->rm(), i->extend8bitL(), diff_8);
  }
  else {
    read_RMW_virtual_byte(i->seg(), RMAddr(i), &op1_8);
    diff_8 = op1_8 - op2_8;
    write_RMW_virtual_byte(diff_8);
  }

  SET_FLAGS_OSZAPC_8(op1_8, op2_8, diff_8, BX_INSTR_SUB8);
}

void BX_CPU_C::SUB_GbEb(bxInstruction_c *i)
{
  Bit8u op1_8, op2_8, diff_8;

  op1_8 = BX_READ_8BIT_REGx(i->nnn(),i->extend8bitL());

  if (i->modC0()) {
    op2_8 = BX_READ_8BIT_REGx(i->rm(),i->extend8bitL());
  }
  else {
    read_virtual_byte(i->seg(), RMAddr(i), &op2_8);
  }

  diff_8 = op1_8 - op2_8;

  BX_WRITE_8BIT_REGx(i->nnn(), i->extend8bitL(), diff_8);

  SET_FLAGS_OSZAPC_8(op1_8, op2_8, diff_8, BX_INSTR_SUB8);
}

void BX_CPU_C::SUB_ALIb(bxInstruction_c *i)
{
  Bit8u op1_8, op2_8, diff_8;

  op1_8 = AL;
  op2_8 = i->Ib();
  diff_8 = op1_8 - op2_8;
  AL = diff_8;

  SET_FLAGS_OSZAPC_8(op1_8, op2_8, diff_8, BX_INSTR_SUB8);
}

void BX_CPU_C::CMP_EbGb(bxInstruction_c *i)
{
  Bit8u op2_8, op1_8;

  op2_8 = BX_READ_8BIT_REGx(i->nnn(),i->extend8bitL());

  if (i->modC0()) {
    op1_8 = BX_READ_8BIT_REGx(i->rm(),i->extend8bitL());
  }
  else {
    read_virtual_byte(i->seg(), RMAddr(i), &op1_8);
  }

#if defined(BX_HostAsm_Cmp8)
  Bit32u flags32;
  asmCmp8(op1_8, op2_8, flags32);
  setEFlagsOSZAPC(flags32);
#else
  Bit8u diff_8 = op1_8 - op2_8;
  SET_FLAGS_OSZAPC_8(op1_8, op2_8, diff_8, BX_INSTR_COMPARE8);
#endif
}

void BX_CPU_C::CMP_GbEb(bxInstruction_c *i)
{
  Bit8u op1_8, op2_8;

  op1_8 = BX_READ_8BIT_REGx(i->nnn(),i->extend8bitL());

  if (i->modC0()) {
    op2_8 = BX_READ_8BIT_REGx(i->rm(),i->extend8bitL());
  }
  else {
    read_virtual_byte(i->seg(), RMAddr(i), &op2_8);
  }

#if defined(BX_HostAsm_Cmp8)
  Bit32u flags32;
  asmCmp8(op1_8, op2_8, flags32);
  setEFlagsOSZAPC(flags32);
#else
  Bit8u diff_8 = op1_8 - op2_8;
  SET_FLAGS_OSZAPC_8(op1_8, op2_8, diff_8, BX_INSTR_COMPARE8);
#endif
}

void BX_CPU_C::CMP_ALIb(bxInstruction_c *i)
{
  Bit8u op1_8 = AL;
  Bit8u op2_8 = i->Ib();

#if defined(BX_HostAsm_Cmp8)
  Bit32u flags32;
  asmCmp8(op1_8, op2_8, flags32);
  setEFlagsOSZAPC(flags32);
#else
  Bit8u diff_8 = op1_8 - op2_8;
  SET_FLAGS_OSZAPC_8(op1_8, op2_8, diff_8, BX_INSTR_COMPARE8);
#endif
}

void BX_CPU_C::XADD_EbGb(bxInstruction_c *i)
{
#if (BX_CPU_LEVEL >= 4) || (BX_CPU_LEVEL_HACKED >= 4)
  Bit8u op2, op1, sum;

  /* XADD dst(r/m8), src(r8)
   * temp <-- src + dst         | sum = op2 + op1
   * src  <-- dst               | op2 = op1
   * dst  <-- tmp               | op1 = sum
   */

  op2 = BX_READ_8BIT_REGx(i->nnn(),i->extend8bitL());

  if (i->modC0()) {
    op1 = BX_READ_8BIT_REGx(i->rm(),i->extend8bitL());
    sum = op1 + op2;
    // and write destination into source
    // Note: if both op1 & op2 are registers, the last one written
    //       should be the sum, as op1 & op2 may be the same register.
    //       For example:  XADD AL, AL
    BX_WRITE_8BIT_REGx(i->nnn(), i->extend8bitL(), op1);
    BX_WRITE_8BIT_REGx(i->rm(), i->extend8bitL(), sum);
  }
  else {
    read_RMW_virtual_byte(i->seg(), RMAddr(i), &op1);
    sum = op1 + op2;
    write_RMW_virtual_byte(sum);
    /* and write destination into source */
    BX_WRITE_8BIT_REGx(i->nnn(), i->extend8bitL(), op1);
  }

  SET_FLAGS_OSZAPC_8(op1, op2, sum, BX_INSTR_ADD8);
#else
  BX_INFO(("XADD_EbGb: not supported on < 80486"));
  UndefinedOpcode(i);
#endif
}

void BX_CPU_C::ADD_EbIb(bxInstruction_c *i)
{
  Bit8u op2, op1, sum;

  op2 = i->Ib();

  if (i->modC0()) {
    op1 = BX_READ_8BIT_REGx(i->rm(),i->extend8bitL());
    sum = op1 + op2;
    BX_WRITE_8BIT_REGx(i->rm(), i->extend8bitL(), sum);
  }
  else {
    read_RMW_virtual_byte(i->seg(), RMAddr(i), &op1);
    sum = op1 + op2;
    write_RMW_virtual_byte(sum);
  }

  SET_FLAGS_OSZAPC_8(op1, op2, sum, BX_INSTR_ADD8);
}

void BX_CPU_C::ADC_EbIb(bxInstruction_c *i)
{
  Bit8u op2, op1, sum;
  bx_bool temp_CF = getB_CF();

  op2 = i->Ib();

  if (i->modC0()) {
    op1 = BX_READ_8BIT_REGx(i->rm(),i->extend8bitL());
    sum = op1 + op2 + temp_CF;
    BX_WRITE_8BIT_REGx(i->rm(), i->extend8bitL(), sum);
  }
  else {
    read_RMW_virtual_byte(i->seg(), RMAddr(i), &op1);
    sum = op1 + op2 + temp_CF;
    write_RMW_virtual_byte(sum);
  }

  SET_FLAGS_OSZAPC_8(op1, op2, sum, BX_INSTR_ADD_ADC8(temp_CF));
}

void BX_CPU_C::SUB_EbIb(bxInstruction_c *i)
{
  Bit8u op2_8, op1_8, diff_8;

  op2_8 = i->Ib();

  if (i->modC0()) {
    op1_8 = BX_READ_8BIT_REGx(i->rm(),i->extend8bitL());
    diff_8 = op1_8 - op2_8;
    BX_WRITE_8BIT_REGx(i->rm(), i->extend8bitL(), diff_8);
  }
  else {
    read_RMW_virtual_byte(i->seg(), RMAddr(i), &op1_8);
    diff_8 = op1_8 - op2_8;
    write_RMW_virtual_byte(diff_8);
  }

  SET_FLAGS_OSZAPC_8(op1_8, op2_8, diff_8, BX_INSTR_SUB8);
}

void BX_CPU_C::CMP_EbIb(bxInstruction_c *i)
{
  Bit8u op2_8, op1_8;

  op2_8 = i->Ib();

  if (i->modC0()) {
    op1_8 = BX_READ_8BIT_REGx(i->rm(),i->extend8bitL());
  }
  else {
    read_virtual_byte(i->seg(), RMAddr(i), &op1_8);
  }

#if defined(BX_HostAsm_Cmp8)
  Bit32u flags32;
  asmCmp8(op1_8, op2_8, flags32);
  setEFlagsOSZAPC(flags32);
#else
  Bit8u diff_8 = op1_8 - op2_8;
  SET_FLAGS_OSZAPC_8(op1_8, op2_8, diff_8, BX_INSTR_COMPARE8);
#endif
}

void BX_CPU_C::NEG_Eb(bxInstruction_c *i)
{
  Bit8u op1_8, diff_8;

  if (i->modC0()) {
    op1_8 = BX_READ_8BIT_REGx(i->rm(),i->extend8bitL());
    diff_8 = -op1_8;
    BX_WRITE_8BIT_REGx(i->rm(), i->extend8bitL(), diff_8);
  }
  else {
    read_RMW_virtual_byte(i->seg(), RMAddr(i), &op1_8);
    diff_8 = -op1_8;
    write_RMW_virtual_byte(diff_8);
  }

  SET_FLAGS_OSZAPC_RESULT_8(diff_8, BX_INSTR_NEG8);
}

void BX_CPU_C::INC_Eb(bxInstruction_c *i)
{
  Bit8u op1;

  if (i->modC0()) {
    op1 = BX_READ_8BIT_REGx(i->rm(),i->extend8bitL());
    op1++;
    BX_WRITE_8BIT_REGx(i->rm(), i->extend8bitL(), op1);
  }
  else {
    read_RMW_virtual_byte(i->seg(), RMAddr(i), &op1);
    op1++;
    write_RMW_virtual_byte(op1);
  }

  SET_FLAGS_OSZAP_RESULT_8(op1, BX_INSTR_INC8);
}

void BX_CPU_C::DEC_Eb(bxInstruction_c *i)
{
  Bit8u op1_8;

  if (i->modC0()) {
    op1_8 = BX_READ_8BIT_REGx(i->rm(),i->extend8bitL());
    op1_8--;
    BX_WRITE_8BIT_REGx(i->rm(), i->extend8bitL(), op1_8);
  }
  else {
    read_RMW_virtual_byte(i->seg(), RMAddr(i), &op1_8);
    op1_8--;
    write_RMW_virtual_byte(op1_8);
  }

  SET_FLAGS_OSZAP_RESULT_8(op1_8, BX_INSTR_DEC8);
}

void BX_CPU_C::CMPXCHG_EbGb(bxInstruction_c *i)
{
#if (BX_CPU_LEVEL >= 4) || (BX_CPU_LEVEL_HACKED >= 4)
  Bit8u op2_8, op1_8, diff_8;

  if (i->modC0()) {
    op1_8 = BX_READ_8BIT_REGx(i->rm(),i->extend8bitL());
  }
  else {
    read_RMW_virtual_byte(i->seg(), RMAddr(i), &op1_8);
  }

  diff_8 = AL - op1_8;

  SET_FLAGS_OSZAPC_8(AL, op1_8, diff_8, BX_INSTR_COMPARE8);

  if (diff_8 == 0) {  // if accumulator == dest
    // dest <-- src
    op2_8 = BX_READ_8BIT_REGx(i->nnn(),i->extend8bitL());

    if (i->modC0()) {
      BX_WRITE_8BIT_REGx(i->rm(), i->extend8bitL(), op2_8);
    }
    else {
      write_RMW_virtual_byte(op2_8);
    }
  }
  else {
    // accumulator <-- dest
    AL = op1_8;
  }

#else
  BX_INFO(("CMPXCHG_EbGb: not supported for cpulevel <= 3"));
  UndefinedOpcode(i);
#endif
}