1 /*

     2     NetWinder Floating Point Emulator

     3     (c) Rebel.COM, 1998,1999

     4 

     5     Direct questions, comments to Scott Bambrough <scottb@netwinder.org>

     6 

     7     This program is free software; you can redistribute it and/or modify

     8     it under the terms of the GNU General Public License as published by

     9     the Free Software Foundation; either version 2 of the License, or

    10     (at your option) any later version.

    11 

    12     This program is distributed in the hope that it will be useful,

    13     but WITHOUT ANY WARRANTY; without even the implied warranty of

    14     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

    15     GNU General Public License for more details.

    16 

    17     You should have received a copy of the GNU General Public License

    18     along with this program; if not, write to the Free Software

    19     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

    20 */

    21 

    22 #include "fpa11.h"

    23 #include "fpopcode.h"

    24 

    25 unsigned int SingleCPDO(const unsigned int opcode);

    26 unsigned int DoubleCPDO(const unsigned int opcode);

    27 unsigned int ExtendedCPDO(const unsigned int opcode);

    28 

    29 unsigned int EmulateCPDO(const unsigned int opcode)

    30 {

    31    FPA11 *fpa11 = GET_FPA11();

    32    unsigned int Fd, nType, nDest, nRc = 1;

    33 

    34    //printk("EmulateCPDO(0x%08x)\n",opcode);

    35 

    36    /* Get the destination size.  If not valid let Linux perform

    37       an invalid instruction trap. */

    38    nDest = getDestinationSize(opcode);

    39    if (typeNone == nDest) return 0;

    40 

    41    SetRoundingMode(opcode);

    42 

    43    /* Compare the size of the operands in Fn and Fm.

    44       Choose the largest size and perform operations in that size,

    45       in order to make use of all the precision of the operands.

    46       If Fm is a constant, we just grab a constant of a size

    47       matching the size of the operand in Fn. */

    48    if (MONADIC_INSTRUCTION(opcode))

    49      nType = nDest;

    50    else

    51      nType = fpa11->fType[getFn(opcode)];

    52 

    53    if (!CONSTANT_FM(opcode))

    54    {

    55      register unsigned int Fm = getFm(opcode);

    56      if (nType < fpa11->fType[Fm])

    57      {

    58         nType = fpa11->fType[Fm];

    59      }

    60    }

    61 

    62    switch (nType)

    63    {

    64       case typeSingle   : nRc = SingleCPDO(opcode);   break;

    65       case typeDouble   : nRc = DoubleCPDO(opcode);   break;

    66       case typeExtended : nRc = ExtendedCPDO(opcode); break;

    67       default           : nRc = 0;

    68    }

    69 

    70    /* If the operation succeeded, check to see if the result in the

    71       destination register is the correct size.  If not force it

    72       to be. */

    73    Fd = getFd(opcode);

    74    nType = fpa11->fType[Fd];

    75    if ((0 != nRc) && (nDest != nType))

    76    {

    77      switch (nDest)

    78      {

    79        case typeSingle:

    80        {

    81          if (typeDouble == nType)

    82            fpa11->fpreg[Fd].fSingle =

    83               float64_to_float32(fpa11->fpreg[Fd].fDouble, &fpa11->fp_status);

    84          else

    85            fpa11->fpreg[Fd].fSingle =

    86               floatx80_to_float32(fpa11->fpreg[Fd].fExtended, &fpa11->fp_status);

    87        }

    88        break;

    89 

    90        case typeDouble:

    91        {

    92          if (typeSingle == nType)

    93            fpa11->fpreg[Fd].fDouble =

    94               float32_to_float64(fpa11->fpreg[Fd].fSingle, &fpa11->fp_status);

    95          else

    96            fpa11->fpreg[Fd].fDouble =

    97               floatx80_to_float64(fpa11->fpreg[Fd].fExtended, &fpa11->fp_status);

    98        }

    99        break;

   100 

   101        case typeExtended:

   102        {

   103          if (typeSingle == nType)

   104            fpa11->fpreg[Fd].fExtended =

   105               float32_to_floatx80(fpa11->fpreg[Fd].fSingle, &fpa11->fp_status);

   106          else

   107            fpa11->fpreg[Fd].fExtended =

   108               float64_to_floatx80(fpa11->fpreg[Fd].fDouble, &fpa11->fp_status);

   109        }

   110        break;

   111      }

   112 

   113      fpa11->fType[Fd] = nDest;

   114    }

   115 

   116    return nRc;

   117 }