newlib/libc/xdr/xdr_float_vax.c

/*
 * Copyright (c) 2009, Sun Microsystems, Inc.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 * - Redistributions of source code must retain the above copyright notice,
 *   this list of conditions and the following disclaimer.
 * - 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.
 * - Neither the name of Sun Microsystems, Inc. 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 HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

/*
 * xdr_float_vax.c, XDR floating point routines for vax.
 *
 * Copyright (C) 1984, Sun Microsystems, Inc.
 *
 * These are the "floating point" xdr routines used to (de)serialize
 * most common data items.  See xdr.h for more info on the interface to
 * xdr.
 */
#ifndef XDR_FLOAT_C
#error "Must be included from xdr_float.c"
#endif

/* What IEEE single precision floating point looks like on a Vax */
struct ieee_single
{
  unsigned int mantissa:23;
  unsigned int exp:8;
  unsigned int sign:1;
};

/* Vax single precision floating point */
struct vax_single
{
  unsigned int mantissa1:7;
  unsigned int exp:8;
  unsigned int sign:1;
  unsigned int mantissa2:16;
};

# define VAX_SNG_BIAS   0x81
# define IEEE_SNG_BIAS  0x7f

/* *INDENT-OFF*
*/
static struct sgl_limits
{
  struct vax_single s;
  struct ieee_single ieee;
} sgl_limits[2] =
{
  {
    {0x7f, 0xff, 0x0, 0xffff},   /* Max Vax */
    {0x0, 0xff, 0x0}             /* Max IEEE */
  },
  {
    {0x0, 0x0, 0x0, 0x0},        /* Min Vax */
    {0x0, 0x0, 0x0}              /* Min IEEE */
  }
};
/* *INDENT-ON*
*/

bool_t
_DEFUN (xdr_float, (xdrs, fp),
       XDR * xdrs _AND
       float *fp)
{
  struct ieee_single is;
  struct vax_single vs, *vsp;
  struct sgl_limits *lim;
  int i;
  switch (xdrs->x_op)
    {

    case XDR_ENCODE:
      vs = *((struct vax_single *) fp);
      for (i = 0, lim = sgl_limits;
           i < sizeof (sgl_limits) / sizeof (struct sgl_limits); i++, lim++)
        {
          if ((vs.mantissa2 == lim->s.mantissa2) &&
              (vs.exp == lim->s.exp) && (vs.mantissa1 == lim->s.mantissa1))
            {
              is = lim->ieee;
              goto shipit;
            }
        }
      is.exp = vs.exp - VAX_SNG_BIAS + IEEE_SNG_BIAS;
      is.mantissa = (vs.mantissa1 << 16) | vs.mantissa2;
    shipit:
      is.sign = vs.sign;
      return (XDR_PUTINT32 (xdrs, (int32_t *) & is));

    case XDR_DECODE:
      vsp = (struct vax_single *) fp;
      if (!XDR_GETINT32 (xdrs, (int32_t *) & is))
        return FALSE;
      for (i = 0, lim = sgl_limits;
           i < sizeof (sgl_limits) / sizeof (struct sgl_limits); i++, lim++)
        {
          if ((is.exp == lim->ieee.exp) &&
              (is.mantissa == lim->ieee.mantissa))
            {
              *vsp = lim->s;
              goto doneit;
            }
        }
      vsp->exp = is.exp - IEEE_SNG_BIAS + VAX_SNG_BIAS;
      vsp->mantissa2 = is.mantissa;
      vsp->mantissa1 = (is.mantissa >> 16);
    doneit:
      vsp->sign = is.sign;
      return TRUE;

    case XDR_FREE:
      return TRUE;
    }
  return FALSE;
}

#if !defined(_DOUBLE_IS_32BITS)

/* What IEEE double precision floating point looks like on a Vax */
struct ieee_double
{
  unsigned int mantissa1:20;
  unsigned int exp:11;
  unsigned int sign:1;
  unsigned int mantissa2:32;
};

/* Vax double precision floating point */
struct vax_double
{
  unsigned int mantissa1:7;
  unsigned int exp:8;
  unsigned int sign:1;
  unsigned int mantissa2:16;
  unsigned int mantissa3:16;
  unsigned int mantissa4:16;
};

# define VAX_DBL_BIAS   0x81
# define IEEE_DBL_BIAS  0x3ff
# define MASK(nbits)    ((1 << nbits) - 1)

/* *INDENT-OFF*
*/
static struct dbl_limits
{
  struct vax_double d;
  struct ieee_double ieee;
} dbl_limits[2] =
{
  {
    {0x7f, 0xff, 0x0, 0xffff, 0xffff, 0xffff},  /* Max Vax */
    {0x0, 0x7ff, 0x0, 0x0}                      /* Max IEEE */
  },
  {
    {0x0, 0x0, 0x0, 0x0, 0x0, 0x0},             /* Min Vax */
    {0x0, 0x0, 0x0, 0x0}                        /* Min IEEE */
  }
};
/* *INDENT-ON*
*/

bool_t
_DEFUN (xdr_double, (xdrs, dp),
        XDR * xdrs _AND
	double *dp)
{
  int32_t *lp;
  struct ieee_double id;
  struct vax_double vd;
  struct dbl_limits *lim;
  int i;

  switch (xdrs->x_op)
    {

    case XDR_ENCODE:
      vd = *((struct vax_double *) dp);
      for (i = 0, lim = dbl_limits;
           i < sizeof (dbl_limits) / sizeof (struct dbl_limits); i++, lim++)
        {
          if ((vd.mantissa4 == lim->d.mantissa4) &&
              (vd.mantissa3 == lim->d.mantissa3) &&
              (vd.mantissa2 == lim->d.mantissa2) &&
              (vd.mantissa1 == lim->d.mantissa1) && (vd.exp == lim->d.exp))
            {
              id = lim->ieee;
              goto shipit;
            }
        }
      id.exp = vd.exp - VAX_DBL_BIAS + IEEE_DBL_BIAS;
      id.mantissa1 = (vd.mantissa1 << 13) | (vd.mantissa2 >> 3);
      id.mantissa2 = ((vd.mantissa2 & MASK (3)) << 29) |
        (vd.mantissa3 << 13) | ((vd.mantissa4 >> 3) & MASK (13));
    shipit:
      id.sign = vd.sign;
      lp = (int32_t *) & id;
      return (XDR_PUTINT32 (xdrs, lp++) && XDR_PUTINT32 (xdrs, lp));

    case XDR_DECODE:
      lp = (int32_t *) & id;
      if (!XDR_GETINT32 (xdrs, lp++) || !XDR_GETINT32 (xdrs, lp))
        return FALSE;
      for (i = 0, lim = dbl_limits;
           i < sizeof (dbl_limits) / sizeof (struct dbl_limits); i++, lim++)
        {
          if ((id.mantissa2 == lim->ieee.mantissa2) &&
              (id.mantissa1 == lim->ieee.mantissa1) &&
              (id.exp == lim->ieee.exp))
            {
              vd = lim->d;
              goto doneit;
            }
        }
      vd.exp = id.exp - IEEE_DBL_BIAS + VAX_DBL_BIAS;
      vd.mantissa1 = (id.mantissa1 >> 13);
      vd.mantissa2 = ((id.mantissa1 & MASK (13)) << 3) | (id.mantissa2 >> 29);
      vd.mantissa3 = (id.mantissa2 >> 13);
      vd.mantissa4 = (id.mantissa2 << 3);
    doneit:
      vd.sign = id.sign;
      *dp = *((double *) &vd);
      return TRUE;

    case XDR_FREE:
      return TRUE;
    }
  return FALSE;
}
#endif /* !_DOUBLE_IS_32BITS */