/////////////////////////////////////////////////////////////////////////
// $Id: stack16.cc,v 1.18 2005-05-20 20:06:50 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"
#define LOG_THIS BX_CPU_THIS_PTR


void BX_CPU_C::PUSH_RX(bxInstruction_c *i)
{
  push_16( BX_CPU_THIS_PTR gen_reg[i->opcodeReg()].word.rx );
}

void BX_CPU_C::POP_RX(bxInstruction_c *i)
{
  Bit16u rx;
  pop_16(&rx);
  BX_CPU_THIS_PTR gen_reg[i->opcodeReg()].word.rx = rx;
}

void BX_CPU_C::POP_Ew(bxInstruction_c *i)
{
  Bit16u val16;

  pop_16(&val16);

  if (i->modC0()) {
    BX_WRITE_16BIT_REG(i->rm(), val16);
  }
  else {
    // Note: there is one little weirdism here.  When 32bit addressing
    // is used, it is possible to use ESP in the modrm addressing.
    // If used, the value of ESP after the pop is used to calculate
    // the address.
    if (i->as32L() && (!i->modC0()) && (i->rm()==4) && (i->sibBase()==4)) {
      BX_CPU_CALL_METHODR (i->ResolveModrm, (i));
    }
    write_virtual_word(i->seg(), RMAddr(i), &val16);
  }
}

void BX_CPU_C::PUSHAD16(bxInstruction_c *i)
{
#if BX_CPU_LEVEL < 2
  BX_INFO(("PUSHAD: not supported on an 8086"));
  UndefinedOpcode(i);
#else
  Bit32u temp_ESP;
  Bit16u sp;

  if (BX_CPU_THIS_PTR sregs[BX_SEG_REG_SS].cache.u.segment.d_b)
    temp_ESP = ESP;
  else
    temp_ESP = SP;

#if BX_CPU_LEVEL >= 2
  if (protected_mode()) {
    if ( !can_push(&BX_CPU_THIS_PTR sregs[BX_SEG_REG_SS].cache, temp_ESP, 16) ) {
      BX_ERROR(("PUSHAD(): stack doesn't have enough room!"));
      exception(BX_SS_EXCEPTION, 0, 0);
      return;
    }
  }
  else
#endif
  {
    if (temp_ESP < 16)
      BX_PANIC(("PUSHAD: eSP < 16"));
  }

  sp = SP;

  /* ??? optimize this by using virtual write, all checks passed */
  push_16(AX);
  push_16(CX);
  push_16(DX);
  push_16(BX);
  push_16(sp);
  push_16(BP);
  push_16(SI);
  push_16(DI);
#endif
}

void BX_CPU_C::POPAD16(bxInstruction_c *i)
{
#if BX_CPU_LEVEL < 2
  BX_INFO(("POPA not supported on an 8086"));
  UndefinedOpcode(i);
#else /* 286+ */

  Bit16u di, si, bp, tmp, bx, dx, cx, ax;

  if (protected_mode()) {
    if ( !can_pop(16) ) {
      BX_ERROR(("POPA: not enough bytes on stack"));
      exception(BX_SS_EXCEPTION, 0, 0);
      return;
    }
  }

  /* ??? optimize this */
  pop_16(&di);
  pop_16(&si);
  pop_16(&bp);
  pop_16(&tmp); /* value for SP discarded */
  pop_16(&bx);
  pop_16(&dx);
  pop_16(&cx);
  pop_16(&ax);

  DI = di;
  SI = si;
  BP = bp;
  BX = bx;
  DX = dx;
  CX = cx;
  AX = ax;
#endif
}

void BX_CPU_C::PUSH_Iw(bxInstruction_c *i)
{
  push_16(i->Iw());
}

void BX_CPU_C::PUSH_Ew(bxInstruction_c *i)
{
  Bit16u op1_16;

  /* op1_16 is a register or memory reference */
  if (i->modC0()) {
    op1_16 = BX_READ_16BIT_REG(i->rm());
  }
  else {
    /* pointer, segment address pair */
    read_virtual_word(i->seg(), RMAddr(i), &op1_16);
  }

  push_16(op1_16);
}