mirror of
https://sourceware.org/git/glibc.git
synced 2024-11-18 02:50:09 +00:00
d876f53279
1999-12-29 Ulrich Drepper <drepper@cygnus.com> * soft-fp/*: Tons of new files to implement floating-point arithmetic in software. Contributed by Richard Henderson, Jakub Jelinek and others.
104 lines
3.7 KiB
C
104 lines
3.7 KiB
C
/* 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 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. */
|
|
|
|
/* 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)
|
|
|