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/* Exception flags and utilities.
Copyright 2001, 2002 Free Software Foundation.
This file is part of the MPFR Library.
The 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 2.1 of the License, or (at your
option) any later version.
The 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 MPFR 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. */
#include "gmp.h"
#include "gmp-impl.h"
#include "mpfr.h"
#include "mpfr-impl.h"
unsigned int __gmpfr_flags = 0;
mp_exp_t __gmpfr_emin = MPFR_EMIN_DEFAULT;
mp_exp_t __gmpfr_emax = MPFR_EMAX_DEFAULT;
#undef mpfr_get_emin
mp_exp_t
mpfr_get_emin (void)
{
return __gmpfr_emin;
}
#undef mpfr_set_emin
int
mpfr_set_emin (mp_exp_t exponent)
{
if (exponent >= MPFR_EMIN_MIN && exponent <= MPFR_EMIN_MAX)
{
__gmpfr_emin = exponent;
return 0;
}
else
{
return 1;
}
}
#undef mpfr_get_emax
mp_exp_t
mpfr_get_emax (void)
{
return __gmpfr_emax;
}
#undef mpfr_set_emax
int
mpfr_set_emax (mp_exp_t exponent)
{
if (exponent >= MPFR_EMAX_MIN && exponent <= MPFR_EMAX_MAX)
{
__gmpfr_emax = exponent;
return 0;
}
else
{
return 1;
}
}
#undef mpfr_clear_flags
void
mpfr_clear_flags (void)
{
__gmpfr_flags = 0;
}
#undef mpfr_clear_underflow
void
mpfr_clear_underflow (void)
{
__gmpfr_flags &= MPFR_FLAGS_ALL ^ MPFR_FLAGS_UNDERFLOW;
}
#undef mpfr_clear_overflow
void
mpfr_clear_overflow (void)
{
__gmpfr_flags &= MPFR_FLAGS_ALL ^ MPFR_FLAGS_OVERFLOW;
}
#undef mpfr_clear_nanflag
void
mpfr_clear_nanflag (void)
{
__gmpfr_flags &= MPFR_FLAGS_ALL ^ MPFR_FLAGS_NAN;
}
#undef mpfr_clear_inexflag
void
mpfr_clear_inexflag (void)
{
__gmpfr_flags &= MPFR_FLAGS_ALL ^ MPFR_FLAGS_INEXACT;
}
#undef mpfr_check_range
int
mpfr_check_range (mpfr_ptr x, int t, mp_rnd_t rnd_mode)
{
if (MPFR_IS_FP(x) && MPFR_NOTZERO(x))
{ /* x is a non-zero FP */
mp_exp_t exp = MPFR_EXP(x);
if (exp < __gmpfr_emin)
{
/* The following test is necessary because in the rounding to the
* nearest mode, mpfr_set_underflow always rounds away from 0. In
* this rounding mode, we need to round to 0 if:
* _ |x| < 2^(emin-2), or
* _ |x| = 2^(emin-2) and the absolute value of the exact
* result is <= 2^(emin-2).
*/
if (rnd_mode == GMP_RNDN &&
(exp + 1 < __gmpfr_emin ||
(mpfr_powerof2_raw(x) &&
(MPFR_SIGN(x) < 0 ? t <= 0 : t >= 0))))
rnd_mode = GMP_RNDZ;
return mpfr_set_underflow(x, rnd_mode, MPFR_SIGN(x));
}
if (exp > __gmpfr_emax)
return mpfr_set_overflow(x, rnd_mode, MPFR_SIGN(x));
}
return t; /* propagate inexact ternary value, unlike most functions */
}
#undef mpfr_underflow_p
int
mpfr_underflow_p (void)
{
return __gmpfr_flags & MPFR_FLAGS_UNDERFLOW;
}
#undef mpfr_overflow_p
int
mpfr_overflow_p (void)
{
return __gmpfr_flags & MPFR_FLAGS_OVERFLOW;
}
#undef mpfr_nanflag_p
int
mpfr_nanflag_p (void)
{
return __gmpfr_flags & MPFR_FLAGS_NAN;
}
#undef mpfr_inexflag_p
int
mpfr_inexflag_p (void)
{
return __gmpfr_flags & MPFR_FLAGS_INEXACT;
}
#undef mpfr_set_underflow
/* Note: In the rounding to the nearest mode, mpfr_set_underflow
always rounds away from 0. In this rounding mode, you must call
mpfr_set_underflow with rnd_mode = GMP_RNDZ if the exact result
is <= 2^(emin-2) in absolute value. */
int
mpfr_set_underflow (mpfr_ptr x, mp_rnd_t rnd_mode, int sign)
{
int inex;
MPFR_CLEAR_FLAGS(x);
if (rnd_mode == GMP_RNDN
|| (rnd_mode == GMP_RNDU && sign > 0)
|| (rnd_mode == GMP_RNDD && sign < 0))
{
mpfr_setmin (x, __gmpfr_emin);
inex = 1;
}
else
{
MPFR_SET_ZERO(x);
inex = -1;
}
if (MPFR_SIGN(x) != sign)
MPFR_CHANGE_SIGN(x);
__gmpfr_flags |= MPFR_FLAGS_INEXACT | MPFR_FLAGS_UNDERFLOW;
return sign > 0 ? inex : -inex;
}
#undef mpfr_set_overflow
int
mpfr_set_overflow (mpfr_ptr x, mp_rnd_t rnd_mode, int sign)
{
int inex;
MPFR_CLEAR_FLAGS(x);
if ((rnd_mode == GMP_RNDU && sign < 0)
|| (rnd_mode == GMP_RNDD && sign > 0))
{
mpfr_setmax (x, __gmpfr_emax);
inex = -1;
}
else
{
MPFR_SET_INF(x);
inex = 1;
}
if (MPFR_SIGN(x) != sign)
MPFR_CHANGE_SIGN(x);
__gmpfr_flags |= MPFR_FLAGS_INEXACT | MPFR_FLAGS_OVERFLOW;
return sign > 0 ? inex : -inex;
}
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