Bochs/bochs/cpu/ctrl_xfer8.cc

/////////////////////////////////////////////////////////////////////////
// $Id: ctrl_xfer8.cc,v 1.27 2008-03-22 21:29:39 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_CPP_AttrRegparmN(1) BX_CPU_C::JCXZ_Jb(bxInstruction_c *i)
{
  // it is impossible to get this instruction in long mode
  BX_ASSERT(i->as64L() == 0);

  Bit32u temp_ECX;

  if (i->as32L())
    temp_ECX = ECX;
  else
    temp_ECX = CX;

  if (temp_ECX == 0) {
    Bit32u new_EIP = EIP + (Bit32s) i->Id();
    if (i->os32L()==0) new_EIP &= 0x0000ffff;
    branch_near32(new_EIP);
    BX_INSTR_CNEAR_BRANCH_TAKEN(BX_CPU_ID, new_EIP);
    return;
  }

  BX_INSTR_CNEAR_BRANCH_NOT_TAKEN(BX_CPU_ID);
}

//
// There is some weirdness in LOOP instructions definition. If an exception
// was generated during the instruction execution (for example #GP fault
// because EIP was beyond CS segment limits) CPU state should restore the
// state prior to instruction execution.
//
// The final point that we are not allowed to decrement ECX register before
// it is known that no exceptions can happen.
//

void BX_CPP_AttrRegparmN(1) BX_CPU_C::LOOPNE_Jb(bxInstruction_c *i)
{
  // it is impossible to get this instruction in long mode
  BX_ASSERT(i->as64L() == 0);

  Bit32u count;

#if BX_CPU_LEVEL >= 3
  if (i->as32L())
    count = ECX;
  else
#endif
    count = CX;

  count--;
  if ((count!=0) && (get_ZF()==0)) {
    Bit32u new_EIP = EIP + (Bit32s) i->Id();
    if (i->os32L()==0) new_EIP &= 0x0000ffff;
    branch_near32(new_EIP);
    BX_INSTR_CNEAR_BRANCH_TAKEN(BX_CPU_ID, new_EIP);
  }
#if BX_INSTRUMENTATION
  else {
    BX_INSTR_CNEAR_BRANCH_NOT_TAKEN(BX_CPU_ID);
  }
#endif

  if (i->as32L())
    ECX--;
  else
     CX--;
}

void BX_CPP_AttrRegparmN(1) BX_CPU_C::LOOPE_Jb(bxInstruction_c *i)
{
  // it is impossible to get this instruction in long mode
  BX_ASSERT(i->as64L() == 0);

  Bit32u count;

#if BX_CPU_LEVEL >= 3
  if (i->as32L())
    count = ECX;
  else
#endif
    count = CX;

  count--;
  if ((count!=0) && get_ZF()) {
    Bit32u new_EIP = EIP + (Bit32s) i->Id();
    if (i->os32L()==0) new_EIP &= 0x0000ffff;
    branch_near32(new_EIP);
    BX_INSTR_CNEAR_BRANCH_TAKEN(BX_CPU_ID, new_EIP);
  }
#if BX_INSTRUMENTATION
  else {
    BX_INSTR_CNEAR_BRANCH_NOT_TAKEN(BX_CPU_ID);
  }
#endif

  if (i->as32L())
    ECX--;
  else
     CX--;
}

void BX_CPP_AttrRegparmN(1) BX_CPU_C::LOOP_Jb(bxInstruction_c *i)
{
  // it is impossible to get this instruction in long mode
  BX_ASSERT(i->as64L() == 0);

  Bit32u count;

#if BX_CPU_LEVEL >= 3
  if (i->as32L())
    count = ECX;
  else
#endif
    count = CX;

  count--;
  if (count != 0) {
    Bit32u new_EIP = EIP + (Bit32s) i->Id();
    if (i->os32L()==0) new_EIP &= 0x0000ffff;
    branch_near32(new_EIP);
    BX_INSTR_CNEAR_BRANCH_TAKEN(BX_CPU_ID, new_EIP);
  }
#if BX_INSTRUMENTATION
  else {
    BX_INSTR_CNEAR_BRANCH_NOT_TAKEN(BX_CPU_ID);
  }
#endif

  if (i->as32L())
    ECX--;
  else
     CX--;
}