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/* mpfr_set_uj -- set a MPFR number from a huge machine unsigned integer
Copyright 2004, 2005 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. */
#if HAVE_CONFIG_H
# include "config.h" /* for a build within gmp */
#endif
/* The ISO C99 standard specifies that in C++ implementations the
INTMAX_MAX, ... macros should only be defined if explicitly requested. */
#if defined(__cplusplus)
# define __STDC_LIMIT_MACROS
# define __STDC_CONSTANT_MACROS
#endif
#ifdef HAVE_STDINT_H
# include <stdint.h>
#endif
#ifdef HAVE_INTTYPES_H
# include <inttypes.h>
#endif
#include <limits.h> /* For CHAR_BIT */
#define MPFR_NEED_LONGLONG_H
#include "mpfr-impl.h"
#ifdef _MPFR_H_HAVE_INTMAX_T
int
mpfr_set_uj (mpfr_t x, uintmax_t j, mp_rnd_t rnd)
{
return mpfr_set_uj_2exp (x, j, 0, rnd);
}
int
mpfr_set_uj_2exp (mpfr_t x, uintmax_t j, intmax_t e, mp_rnd_t rnd)
{
unsigned int cnt, i;
mp_size_t k, len;
mp_limb_t limb;
mp_limb_t yp[sizeof(uintmax_t)/sizeof(mp_limb_t)];
mpfr_t y;
/* Special case */
if (j == 0)
{
MPFR_SET_POS(x);
MPFR_SET_ZERO(x);
MPFR_RET(0);
}
/* Create an auxillary var */
MPFR_TMP_INIT1 (yp, y, sizeof(uintmax_t)*CHAR_BIT);
for (i = 0 ; i < numberof (yp) ; i++, j>>=BITS_PER_MP_LIMB)
yp[i] = j; /* Only the low bits are copied */
/* Find the first limb not equal to zero. */
k = numberof (yp);
do {
MPFR_ASSERTD( k > 0 );
limb = yp[--k];
} while (limb == 0);
count_leading_zeros(cnt, limb);
k++;
len = numberof (yp) - k;
/* Normalize it: len = number of last 0 limb, k number of non-zero limbs */
if (MPFR_LIKELY(cnt))
mpn_lshift (yp+len, yp, k, cnt); /* Normalize the High Limb*/
else if (len != 0)
MPN_COPY_DECR (yp+len, yp, k); /* Must use DECR */
MPN_ZERO (yp, len); /* Zeroing the last limbs */
e = e + k*BITS_PER_MP_LIMB - cnt; /* Update Expo */
MPFR_ASSERTD (MPFR_LIMB_MSB(yp[numberof(yp)-1]) != 0);
/* Check expo underflow / overflow (can't use mpfr_check_range) */
if (MPFR_UNLIKELY(e < __gmpfr_emin))
{
/* The following test is necessary because in the rounding to the
* nearest mode, mpfr_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 == GMP_RNDN && (e+1 < __gmpfr_emin || mpfr_powerof2_raw(y)))
rnd = GMP_RNDZ;
return mpfr_underflow (x, rnd, MPFR_SIGN_POS);
}
if (MPFR_UNLIKELY(e > __gmpfr_emax))
return mpfr_overflow (x, rnd, MPFR_SIGN_POS);
MPFR_SET_EXP (y, e);
/* Final: set x to y (rounding if necessary) */
return mpfr_set (x, y, rnd);
}
#endif
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