vasilito
ff4ff35918
Red Bear OS is a full fork. All sources must be available from git clone with zero network access. Removed gitignore rules that excluded fetched source trees under recipes/*/source/, local/recipes/kde/*/source/, local/recipes/qt/*/source/, and vendor source trees. Build artifacts (target/, build/, source.tar, *.o, *.so) remain excluded. 127291 files added — kernel, relibc, base, bootloader, pkgar, all KDE/Qt frameworks, mesa, wayland, DRM drivers, and every other recipe source.
136 lines
4.1 KiB
C
136 lines
4.1 KiB
C
/* mpfr_round_p -- check if an approximation is roundable.
|
|
|
|
Copyright 2005-2025 Free Software Foundation, Inc.
|
|
Contributed by the Pascaline and Caramba projects, INRIA.
|
|
|
|
This file is part of the GNU MPFR Library.
|
|
|
|
The GNU MPFR 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 3 of the License, or (at your
|
|
option) any later version.
|
|
|
|
The GNU MPFR 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 MPFR Library; see the file COPYING.LESSER.
|
|
If not, see <https://www.gnu.org/licenses/>. */
|
|
|
|
#include "mpfr-impl.h"
|
|
|
|
/* Check against mpfr_can_round? */
|
|
#if MPFR_WANT_ASSERT >= 2
|
|
int mpfr_round_p_2 (mp_limb_t *, mp_size_t, mpfr_exp_t, mpfr_prec_t);
|
|
int
|
|
mpfr_round_p (mp_limb_t *bp, mp_size_t bn, mpfr_exp_t err0, mpfr_prec_t prec)
|
|
{
|
|
int i1, i2;
|
|
|
|
MPFR_ASSERTN(bp[bn - 1] & MPFR_LIMB_HIGHBIT);
|
|
|
|
i1 = mpfr_round_p_2 (bp, bn, err0, prec);
|
|
|
|
/* Note: since revision 10747, mpfr_can_round_raw is supposed to be always
|
|
correct, whereas mpfr_round_p_2 might return 0 in some cases where one
|
|
could round, for example with err0=67 and prec=54:
|
|
b = 1111101101010001100011111011100010100011101111011011101111111111
|
|
thus we cannot compare i1 and i2, we only can check that we don't have
|
|
i1 <> 0 and i2 = 0.
|
|
*/
|
|
i2 = mpfr_can_round_raw (bp, bn, MPFR_SIGN_POS, err0,
|
|
MPFR_RNDN, MPFR_RNDZ, prec);
|
|
if (i1 && (i2 == 0))
|
|
{
|
|
fprintf (stderr, "mpfr_round_p(%d) != mpfr_can_round(%d)!\n"
|
|
"bn = %lu, err0 = %ld, prec = %lu\nbp = ", i1, i2,
|
|
(unsigned long) bn, (long) err0, (unsigned long) prec);
|
|
#ifndef MPFR_USE_MINI_GMP
|
|
gmp_fprintf (stderr, "%NX\n", bp, bn);
|
|
#endif
|
|
MPFR_ASSERTN (0);
|
|
}
|
|
|
|
return i1;
|
|
}
|
|
# define mpfr_round_p mpfr_round_p_2
|
|
#endif /* MPFR_WANT_ASSERT >= 2 */
|
|
|
|
/*
|
|
* Assuming {bp, bn} is an approximation of a non-singular number
|
|
* with error at most equal to 2^(EXP(b)-err0) (`err0' bits of b are known)
|
|
* of direction unknown, check if we can round b toward zero with
|
|
* precision prec.
|
|
*/
|
|
int
|
|
mpfr_round_p (mp_limb_t *bp, mp_size_t bn, mpfr_exp_t err0, mpfr_prec_t prec)
|
|
{
|
|
mpfr_prec_t err;
|
|
mp_size_t k, n;
|
|
mp_limb_t tmp, mask;
|
|
int s;
|
|
|
|
MPFR_ASSERTD(bp[bn - 1] & MPFR_LIMB_HIGHBIT);
|
|
|
|
err = (mpfr_prec_t) bn * GMP_NUMB_BITS;
|
|
if (MPFR_UNLIKELY (err0 <= 0 || (mpfr_uexp_t) err0 <= prec || prec >= err))
|
|
return 0; /* can't round */
|
|
err = MIN (err, (mpfr_uexp_t) err0);
|
|
|
|
k = prec / GMP_NUMB_BITS;
|
|
s = GMP_NUMB_BITS - prec % GMP_NUMB_BITS;
|
|
n = err / GMP_NUMB_BITS - k;
|
|
|
|
MPFR_ASSERTD (n >= 0);
|
|
MPFR_ASSERTD (bn > k);
|
|
|
|
/* Check first limb */
|
|
bp += bn - 1 - k;
|
|
tmp = *bp--;
|
|
mask = s == GMP_NUMB_BITS ? MPFR_LIMB_MAX : MPFR_LIMB_MASK (s);
|
|
tmp &= mask;
|
|
|
|
if (MPFR_LIKELY (n == 0))
|
|
{
|
|
/* prec and error are in the same limb */
|
|
s = GMP_NUMB_BITS - err % GMP_NUMB_BITS;
|
|
MPFR_ASSERTD (s < GMP_NUMB_BITS);
|
|
tmp >>= s;
|
|
mask >>= s;
|
|
return tmp != 0 && tmp != mask;
|
|
}
|
|
else if (MPFR_UNLIKELY (tmp == 0))
|
|
{
|
|
/* Check if all (n-1) limbs are 0 */
|
|
while (--n)
|
|
if (*bp-- != 0)
|
|
return 1;
|
|
/* Check if final error limb is 0 */
|
|
s = GMP_NUMB_BITS - err % GMP_NUMB_BITS;
|
|
if (s == GMP_NUMB_BITS)
|
|
return 0;
|
|
tmp = *bp >> s;
|
|
return tmp != 0;
|
|
}
|
|
else if (MPFR_UNLIKELY (tmp == mask))
|
|
{
|
|
/* Check if all (n-1) limbs are 11111111111111111 */
|
|
while (--n)
|
|
if (*bp-- != MPFR_LIMB_MAX)
|
|
return 1;
|
|
/* Check if final error limb is 0 */
|
|
s = GMP_NUMB_BITS - err % GMP_NUMB_BITS;
|
|
if (s == GMP_NUMB_BITS)
|
|
return 0;
|
|
tmp = *bp >> s;
|
|
return tmp != (MPFR_LIMB_MAX >> s);
|
|
}
|
|
else
|
|
{
|
|
/* First limb is different from 000000 or 1111111 */
|
|
return 1;
|
|
}
|
|
}
|