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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 (rth@cygnus.com),
Jakub Jelinek (jj@ultra.linux.cz) and
Peter Maydell (pmaydell@chiark.greenend.org.uk).
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
/* 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)
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