cpu/mult16.cc

   1 /////////////////////////////////////////////////////////////////////////
   2 // $Id: mult16.cc,v 1.32 2008/08/10 21:16:12 sshwarts Exp $
   3 /////////////////////////////////////////////////////////////////////////
   4 //
   5 //  Copyright (C) 2001  MandrakeSoft S.A.
   6 //
   7 //    MandrakeSoft S.A.
   8 //    43, rue d'Aboukir
   9 //    75002 Paris - France
  10 //    http://www.linux-mandrake.com/
  11 //    http://www.mandrakesoft.com/
  12 //
  13 //  This library is free software; you can redistribute it and/or
  14 //  modify it under the terms of the GNU Lesser General Public
  15 //  License as published by the Free Software Foundation; either
  16 //  version 2 of the License, or (at your option) any later version.
  17 //
  18 //  This library is distributed in the hope that it will be useful,
  19 //  but WITHOUT ANY WARRANTY; without even the implied warranty of
  20 //  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  21 //  Lesser General Public License for more details.
  22 //
  23 //  You should have received a copy of the GNU Lesser General Public
  24 //  License along with this library; if not, write to the Free Software
  25 //  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
  26 /////////////////////////////////////////////////////////////////////////
  27
  28 #define NEED_CPU_REG_SHORTCUTS 1
  29 #include "bochs.h"
  30 #include "cpu.h"
  31 #define LOG_THIS BX_CPU_THIS_PTR
  32
  33 void BX_CPP_AttrRegparmN(1) BX_CPU_C::MUL_AXEwR(bxInstruction_c *i)
  34 {
  35   Bit16u op1_16 = AX;
  36   Bit16u op2_16 = BX_READ_16BIT_REG(i->rm());
  37
  38   Bit32u product_32  = ((Bit32u) op1_16) * ((Bit32u) op2_16);
  39   Bit16u product_16l = (product_32 & 0xFFFF);
  40   Bit16u product_16h =  product_32 >> 16;
  41
  42   /* now write product back to destination */
  43   AX = product_16l;
  44   DX = product_16h;
  45
  46   /* set EFLAGS */
  47   SET_FLAGS_OSZAPC_LOGIC_16(product_16l);
  48   if(product_16h != 0)
  49   {
  50     ASSERT_FLAGS_OxxxxC();
  51   }
  52 }
  53
  54 void BX_CPP_AttrRegparmN(1) BX_CPU_C::IMUL_AXEwR(bxInstruction_c *i)
  55 {
  56   Bit16s op1_16 = AX;
  57   Bit16s op2_16 = BX_READ_16BIT_REG(i->rm());
  58
  59   Bit32s product_32  = ((Bit32s) op1_16) * ((Bit32s) op2_16);
  60   Bit16u product_16l = (product_32 & 0xFFFF);
  61   Bit16u product_16h = product_32 >> 16;
  62
  63   /* now write product back to destination */
  64   AX = product_16l;
  65   DX = product_16h;
  66
  67   /* set eflags:
  68    * IMUL r/m16: condition for clearing CF & OF:
  69    *   DX:AX = sign-extend of AX
  70    */
  71   SET_FLAGS_OSZAPC_LOGIC_16(product_16l);
  72   if(product_32 != (Bit16s)product_32)
  73   {
  74     ASSERT_FLAGS_OxxxxC();
  75   }
  76 }
  77
  78 void BX_CPP_AttrRegparmN(1) BX_CPU_C::DIV_AXEwR(bxInstruction_c *i)
  79 {
  80   Bit16u op2_16 = BX_READ_16BIT_REG(i->rm());
  81   if (op2_16 == 0)
  82     exception(BX_DE_EXCEPTION, 0, 0);
  83
  84   Bit32u op1_32 = (((Bit32u) DX) << 16) | ((Bit32u) AX);
  85
  86   Bit32u quotient_32  = op1_32 / op2_16;
  87   Bit16u remainder_16 = op1_32 % op2_16;
  88   Bit16u quotient_16l = quotient_32 & 0xFFFF;
  89
  90   if (quotient_32 != quotient_16l)
  91     exception(BX_DE_EXCEPTION, 0, 0);
  92
  93   /* now write quotient back to destination */
  94   AX = quotient_16l;
  95   DX = remainder_16;
  96 }
  97
  98 void BX_CPP_AttrRegparmN(1) BX_CPU_C::IDIV_AXEwR(bxInstruction_c *i)
  99 {
 100   Bit32s op1_32 = ((((Bit32u) DX) << 16) | ((Bit32u) AX));
 101
 102   /* check MIN_INT case */
 103   if (op1_32 == ((Bit32s)0x80000000))
 104     exception(BX_DE_EXCEPTION, 0, 0);
 105
 106   Bit16s op2_16 = BX_READ_16BIT_REG(i->rm());
 107
 108   if (op2_16 == 0)
 109     exception(BX_DE_EXCEPTION, 0, 0);
 110
 111   Bit32s quotient_32  = op1_32 / op2_16;
 112   Bit16s remainder_16 = op1_32 % op2_16;
 113   Bit16s quotient_16l = quotient_32 & 0xFFFF;
 114
 115   if (quotient_32 != quotient_16l)
 116     exception(BX_DE_EXCEPTION, 0, 0);
 117
 118   /* now write quotient back to destination */
 119   AX = quotient_16l;
 120   DX = remainder_16;
 121 }
 122
 123 void BX_CPP_AttrRegparmN(1) BX_CPU_C::IMUL_GwEwIwR(bxInstruction_c *i)
 124 {
 125   Bit16s op2_16 = BX_READ_16BIT_REG(i->rm());
 126   Bit16s op3_16 = i->Iw();
 127
 128   Bit32s product_32  = op2_16 * op3_16;
 129   Bit16u product_16 = (product_32 & 0xFFFF);
 130
 131   /* now write product back to destination */
 132   BX_WRITE_16BIT_REG(i->nnn(), product_16);
 133
 134   /* set eflags:
 135    * IMUL r16,r/m16,imm16: condition for clearing CF & OF:
 136    *   result exactly fits within r16
 137    */
 138   SET_FLAGS_OSZAPC_LOGIC_16(product_16);
 139   if(product_32 != (Bit16s) product_32)
 140   {
 141     ASSERT_FLAGS_OxxxxC();
 142   }
 143 }
 144
 145 void BX_CPP_AttrRegparmN(1) BX_CPU_C::IMUL_GwEwR(bxInstruction_c *i)
 146 {
 147   Bit16s op1_16 = BX_READ_16BIT_REG(i->nnn());
 148   Bit16s op2_16 = BX_READ_16BIT_REG(i->rm());
 149
 150   Bit32s product_32 = op1_16 * op2_16;
 151   Bit16u product_16 = (product_32 & 0xFFFF);
 152
 153   /* now write product back to destination */
 154   BX_WRITE_16BIT_REG(i->nnn(), product_16);
 155
 156   /* set eflags:
 157    * IMUL r16,r/m16: condition for clearing CF & OF:
 158    *   result exactly fits within r16
 159    */
 160   SET_FLAGS_OSZAPC_LOGIC_16(product_16);
 161   if(product_32 != (Bit16s) product_32)
 162   {
 163     ASSERT_FLAGS_OxxxxC();
 164   }
 165 }