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/*

 * Copyright (c) 2002-2005 The TenDRA Project <http://www.tendra.org/>.

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions are met:

 *

 * 1. Redistributions of source code must retain the above copyright notice,

 *    this list of conditions and the following disclaimer.

 * 2. Redistributions in binary form must reproduce the above copyright notice,

 *    this list of conditions and the following disclaimer in the documentation

 *    and/or other materials provided with the distribution.

 * 3. Neither the name of The TenDRA Project nor the names of its contributors

 *    may be used to endorse or promote products derived from this software

 *    without specific, prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS

 * IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,

 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR

 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR

 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,

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 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 *

 * $Id$

 */

/*

    		 Crown Copyright (c) 1997

    This TenDRA(r) Computer Program is subject to Copyright

    owned by the United Kingdom Secretary of State for Defence

    acting through the Defence Evaluation and Research Agency

    (DERA).  It is made available to Recipients with a

    royalty-free licence for its use, reproduction, transfer

    to other parties and amendment for any purpose not excluding

    product development provided that any such use et cetera

    shall be deemed to be acceptance of the following conditions:-

        (1) Its Recipients shall ensure that this Notice is

        reproduced upon any copies or amended versions of it;

        (2) Any amended version of it shall be clearly marked to

        show both the nature of and the organisation responsible

        for the relevant amendment or amendments;

        (3) Its onward transfer from a recipient to another

        party shall be deemed to be that party's acceptance of

        these conditions;

        (4) DERA gives no warranty or assurance as to its

        quality or suitability for any purpose and DERA accepts

        no liability whatsoever in relation to any use to which

        it may be put.

*/

/**********************************************************************

$Author: release $

$Date: 1998/01/17 15:55:47 $

$Revision: 1.1.1.1 $

$Log: f64.c,v $

 * Revision 1.1.1.1  1998/01/17  15:55:47  release

 * First version to be checked into rolling release.

 *

 * Revision 1.1  1995/04/06  10:44:05  currie

 * Initial revision

 *

***********************************************************************/

#include "config.h"

#include "common_types.h"

#include "flpttypes.h"

#include "messages_c.h"

#include "flpt.h"

#include "basicread.h"

#include "expmacs.h"

#include "exp.h"

#include "f64.h"

/* PROCEDURES */

flt64

flt_to_f64(flpt fp, int sg, int *ov)

{

  flt *f = &flptnos[fp];

  flt64 res;

  int i = f->exp;

  *ov = 0;

  if (f->sign == 0 || i < 0) {

    res.big = 0;

    res.small = 0;

  } else {

    res.big = 0;

    res.small = f->mant[i];

    if (i > 0) {

      res.small += (unsigned int)(f->mant[i - 1] << 16);

    }

    if (i > 1) {

      res.big = (int)f->mant[i - 2];

    }

    if (i > 2) {

      res.big += (int)(f->mant[i - 3] << 16);

    }

    if (i > 3 || (sg && res.big < 0)) {

      *ov = 1;

    }

  }

  if (f->sign == -1) {

    res.small = ~res.small;

    res.big = ~res.big;

    if (res.small == 0xffffffff) {

      ++res.big;

    }

    ++res.small;

  }

  return res;

}

flpt

f64_to_flt(flt64 a, int sg)

{

  flpt r = new_flpt();

  flt *res = &flptnos[r];

  flt_zero(res);

  if (a.big == 0 && a.small == 0) {

    return r;

  }

  if (sg && a.big < 0) {

    a.small = ~a.small;

    a.big = ~a.big;

    if (a.small == 0xffffffff) {

      ++a.big;

    }

    ++a.small;

    res->sign = -1;

  } else {

    res->sign = 1;

  }

  if (a.big == 0) {

    if ((a.small & 0xffff0000) == 0) {

      res->exp = 0;

      res->mant[0] = (unsigned short)(a.small & 0xffff);

    } else {

      res->exp = 1;

      res->mant[0] = (unsigned short)((a.small & 0xffff0000) >> 16);

      res->mant[1] = (unsigned short)(a.small & 0xffff);

    }

  } else {

    if ((a.big & (int)0xffff0000) == 0) {

      res->exp = 2;

      res->mant[0] = (unsigned short)(a.big & 0xffff);

      res->mant[1] = (unsigned short)((a.small & 0xffff0000) >> 16);

      res->mant[2] = (unsigned short)(a.small & 0xffff);

    } else {

      res->exp = 3;

      res->mant[0] = (unsigned short)(((unsigned int)a.big >> 16) & 0xffff);

      res->mant[1] = (unsigned short)(a.big & 0xffff);

      res->mant[2] = (unsigned short)((a.small & 0xffff0000) >> 16);

      res->mant[3] = (unsigned short)(a.small & 0xffff);

    }

  }

  return r;

}

int

f64_to_flpt(flt64 a, int sg, int *pr, int sz)

{

  int t = (int)a.small;

  *pr = 0;

  if (sg && (t >> 31) == a.big) {

    return t;

  }

  if (!sg && a.big == 0 && ((a.small & 0x80000000) == 0 || sz <= 32)) {

    return t;

  }

  *pr = 1;

  return f64_to_flt(a, sg);

}

flt64

int_to_f64(int i, int sg)

{

  flt64 res;

  res.small = (unsigned int)i;

  if (sg && i < 0) {

    res.big = -1;

  } else {

    res.big = 0;

  }

  return res;

}

flt64

exp_to_f64(exp e)

{

  int ov;

  if (isbigval(e)) {

    return flt_to_f64(no(e), is_signed(sh(e)), &ov);

  }

  return int_to_f64(no(e), is_signed(sh(e)));

}