// Copyright Notice
// ================
// BOCHS is Copyright 1994-1999 by Kevin P. Lawton.
//
// BOCHS is commercial software.
//
// For more information, read the file 'LICENSE' included in the bochs
// distribution.  If you don't have access to this file, or have questions
// regarding the licensing policy, the author may be contacted via:
//
//     US Mail:  Kevin Lawton
//               439 Marrett Rd.
//               Lexington, MA 02421-7714
//
//     EMail:    bochs@world.std.com








#include "bochs.h"


  void
BX_CPU_C::PUSH_RX(BxInstruction_t *i)
{
  push_16( BX_CPU_THIS_PTR gen_reg[i->b1 & 0x07].word.rx );
}

  void
BX_CPU_C::POP_RX(BxInstruction_t *i)
{
  Bit16u rx;

  pop_16(&rx);
  BX_CPU_THIS_PTR gen_reg[i->b1 & 0x07].word.rx = rx;
}

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

  pop_16(&val16);

  if (i->mod == 0xc0) {
    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->as_32 && (i->mod!=0xc0) && (i->rm==4) && (i->base==4)) {
      i->ResolveModrm(i);
      }
    write_virtual_word(i->seg, i->rm_addr, &val16);
    }
}

  void
BX_CPU_C::PUSHAD16(BxInstruction_t *i)
{
#if BX_CPU_LEVEL < 2
  bx_panic("PUSHAD: not supported on an 8086\n");
#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_panic("PUSHA(): stack doesn't have enough room!\n");
        exception(BX_SS_EXCEPTION, 0, 0);
        return;
        }
      }
    else
#endif
      {
      if (temp_ESP < 16)
        bx_panic("pushad: eSP < 16\n");
      }

    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_t *i)
{
#if BX_CPU_LEVEL < 2
  bx_panic("POPAD not supported on an 8086\n");
#else /* 286+ */

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

    if (protected_mode()) {
      if ( !can_pop(16) ) {
        bx_panic("pop_a: not enough bytes on stack\n");
        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_t *i)
{
#if BX_CPU_LEVEL < 2
  bx_panic("PUSH_Iv: not supported on 8086!\n");
#else

    Bit16u imm16;

    imm16 = i->Iw;

    push_16(imm16);
#endif
}

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

    /* op1_16 is a register or memory reference */
    if (i->mod == 0xc0) {
      op1_16 = BX_READ_16BIT_REG(i->rm);
      }
    else {
      /* pointer, segment address pair */
      read_virtual_word(i->seg, i->rm_addr, &op1_16);
      }

    push_16(op1_16);
}
