op-8.h

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/* Software floating-point emulation.
   Basic eight-word fraction declaration and manipulation.
   Copyright (C) 1997,1998,1999 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Richard Henderson ([email protected]),
          Jakub Jelinek ([email protected]) and
          Peter Maydell ([email protected]).
                                                         
   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Library General Public License as
   published by the Free Software Foundation; either version 2 of the
   License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Library General Public License for more details.

   You should have received a copy of the GNU Library General Public
   License along with the GNU C Library; see the file COPYING.LIB.  If
   not, write to the Free Software Foundation, Inc.,
   59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */

#ifndef __MATH_EMU_OP_8_H__
#define __MATH_EMU_OP_8_H__

/* We need just a few things from here for op-4, if we ever need some
   other macros, they can be added. */
#define _FP_FRAC_DECL_8(X)  _FP_W_TYPE X##_f[8]
#define _FP_FRAC_HIGH_8(X)  (X##_f[7])
#define _FP_FRAC_LOW_8(X)   (X##_f[0])
#define _FP_FRAC_WORD_8(X,w)    (X##_f[w])

#define _FP_FRAC_SLL_8(X,N)                     \
  do {                                  \
    _FP_I_TYPE _up, _down, _skip, _i;                   \
    _skip = (N) / _FP_W_TYPE_SIZE;                  \
    _up = (N) % _FP_W_TYPE_SIZE;                    \
    _down = _FP_W_TYPE_SIZE - _up;                  \
    if (!_up)                               \
      for (_i = 7; _i >= _skip; --_i)                   \
    X##_f[_i] = X##_f[_i-_skip];                    \
    else                                \
      {                                 \
    for (_i = 7; _i > _skip; --_i)                  \
      X##_f[_i] = X##_f[_i-_skip] << _up                \
              | X##_f[_i-_skip-1] >> _down;         \
    X##_f[_i--] = X##_f[0] << _up;                  \
      }                                 \
    for (; _i >= 0; --_i)                       \
      X##_f[_i] = 0;                            \
  } while (0)

#define _FP_FRAC_SRL_8(X,N)                     \
  do {                                  \
    _FP_I_TYPE _up, _down, _skip, _i;                   \
    _skip = (N) / _FP_W_TYPE_SIZE;                  \
    _down = (N) % _FP_W_TYPE_SIZE;                  \
    _up = _FP_W_TYPE_SIZE - _down;                  \
    if (!_down)                             \
      for (_i = 0; _i <= 7-_skip; ++_i)                 \
    X##_f[_i] = X##_f[_i+_skip];                    \
    else                                \
      {                                 \
    for (_i = 0; _i < 7-_skip; ++_i)                \
      X##_f[_i] = X##_f[_i+_skip] >> _down              \
              | X##_f[_i+_skip+1] << _up;           \
    X##_f[_i++] = X##_f[7] >> _down;                \
      }                                 \
    for (; _i < 8; ++_i)                        \
      X##_f[_i] = 0;                            \
  } while (0)


/* Right shift with sticky-lsb. 
 * What this actually means is that we do a standard right-shift,
 * but that if any of the bits that fall off the right hand side
 * were one then we always set the LSbit.
 */
#define _FP_FRAC_SRS_8(X,N,size)                    \
  do {                                  \
    _FP_I_TYPE _up, _down, _skip, _i;                   \
    _FP_W_TYPE _s;                          \
    _skip = (N) / _FP_W_TYPE_SIZE;                  \
    _down = (N) % _FP_W_TYPE_SIZE;                  \
    _up = _FP_W_TYPE_SIZE - _down;                  \
    for (_s = _i = 0; _i < _skip; ++_i)                 \
      _s |= X##_f[_i];                          \
    _s |= X##_f[_i] << _up;                     \
/* s is now != 0 if we want to set the LSbit */             \
    if (!_down)                             \
      for (_i = 0; _i <= 7-_skip; ++_i)                 \
    X##_f[_i] = X##_f[_i+_skip];                    \
    else                                \
      {                                 \
    for (_i = 0; _i < 7-_skip; ++_i)                \
      X##_f[_i] = X##_f[_i+_skip] >> _down              \
              | X##_f[_i+_skip+1] << _up;           \
    X##_f[_i++] = X##_f[7] >> _down;                \
      }                                 \
    for (; _i < 8; ++_i)                        \
      X##_f[_i] = 0;                            \
    /* don't fix the LSB until the very end when we're sure f[0] is stable */   \
    X##_f[0] |= (_s != 0);                      \
  } while (0)

#endif