--- /dev/null
+/* mpfr_set_d -- convert a machine double precision float to
+ a multiple precision floating-point number
+
+Copyright 1999, 2000, 2001, 2002, 2003, 2004, 2006, 2007, 2008, 2009 Free Software Foundation, Inc.
+Contributed by the Arenaire and Cacao 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 2.1 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.LIB. If not, write to
+the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston,
+MA 02110-1301, USA. */
+
+#include <string.h> /* For memcmp if _GMP_IEEE_FLOAT == 0 */
+#include <float.h> /* For DOUBLE_ISINF and DOUBLE_ISNAN */
+
+#define MPFR_NEED_LONGLONG_H
+#include "mpfr-impl.h"
+
+/* extracts the bits of d in rp[0..n-1] where n=ceil(53/BITS_PER_MP_LIMB).
+ Assumes d is neither 0 nor NaN nor Inf. */
+static long
+__gmpfr_extract_double (mp_ptr rp, double d)
+ /* e=0 iff BITS_PER_MP_LIMB=32 and rp has only one limb */
+{
+ long exp;
+ mp_limb_t manl;
+#if BITS_PER_MP_LIMB == 32
+ mp_limb_t manh;
+#endif
+
+ /* BUGS
+ 1. Should handle Inf and NaN in IEEE specific code.
+ 2. Handle Inf and NaN also in default code, to avoid hangs.
+ 3. Generalize to handle all BITS_PER_MP_LIMB.
+ 4. This lits is incomplete and misspelled.
+ */
+
+ MPFR_ASSERTD(!DOUBLE_ISNAN(d));
+ MPFR_ASSERTD(!DOUBLE_ISINF(d));
+ MPFR_ASSERTD(d != 0.0);
+
+#if _GMP_IEEE_FLOATS
+
+ {
+ union ieee_double_extract x;
+ x.d = d;
+
+ exp = x.s.exp;
+ if (exp)
+ {
+#if BITS_PER_MP_LIMB >= 64
+ manl = ((MPFR_LIMB_ONE << 63)
+ | ((mp_limb_t) x.s.manh << 43) | ((mp_limb_t) x.s.manl << 11));
+#else
+ manh = (MPFR_LIMB_ONE << 31) | (x.s.manh << 11) | (x.s.manl >> 21);
+ manl = x.s.manl << 11;
+#endif
+ }
+ else /* denormalized number */
+ {
+#if BITS_PER_MP_LIMB >= 64
+ manl = ((mp_limb_t) x.s.manh << 43) | ((mp_limb_t) x.s.manl << 11);
+#else
+ manh = (x.s.manh << 11) /* high 21 bits */
+ | (x.s.manl >> 21); /* middle 11 bits */
+ manl = x.s.manl << 11; /* low 21 bits */
+#endif
+ }
+
+ if (exp)
+ exp -= 1022;
+ else
+ exp = -1021;
+ }
+
+#else /* _GMP_IEEE_FLOATS */
+
+ {
+ /* Unknown (or known to be non-IEEE) double format. */
+ exp = 0;
+ if (d >= 1.0)
+ {
+ MPFR_ASSERTN (d * 0.5 != d);
+ while (d >= 32768.0)
+ {
+ d *= (1.0 / 65536.0);
+ exp += 16;
+ }
+ while (d >= 1.0)
+ {
+ d *= 0.5;
+ exp += 1;
+ }
+ }
+ else if (d < 0.5)
+ {
+ while (d < (1.0 / 65536.0))
+ {
+ d *= 65536.0;
+ exp -= 16;
+ }
+ while (d < 0.5)
+ {
+ d *= 2.0;
+ exp -= 1;
+ }
+ }
+
+ d *= MP_BASE_AS_DOUBLE;
+#if BITS_PER_MP_LIMB >= 64
+ manl = d;
+#else
+ manh = (mp_limb_t) d;
+ manl = (mp_limb_t) ((d - manh) * MP_BASE_AS_DOUBLE);
+#endif
+ }
+
+#endif /* _GMP_IEEE_FLOATS */
+
+#if BITS_PER_MP_LIMB >= 64
+ rp[0] = manl;
+#else
+ rp[1] = manh;
+ rp[0] = manl;
+#endif
+
+ return exp;
+}
+
+/* End of part included from gmp-2.0.2 */
+
+int
+mpfr_set_d (mpfr_ptr r, double d, mp_rnd_t rnd_mode)
+{
+ int signd, inexact;
+ unsigned int cnt;
+ mp_size_t i, k;
+ mpfr_t tmp;
+ mp_limb_t tmpmant[MPFR_LIMBS_PER_DOUBLE];
+ MPFR_SAVE_EXPO_DECL (expo);
+
+ MPFR_CLEAR_FLAGS(r);
+
+ if (MPFR_UNLIKELY(DOUBLE_ISNAN(d)))
+ {
+ MPFR_SET_NAN(r);
+ MPFR_RET_NAN;
+ }
+ else if (MPFR_UNLIKELY(d == 0))
+ {
+#if _GMP_IEEE_FLOATS
+ union ieee_double_extract x;
+
+ MPFR_SET_ZERO(r);
+ /* set correct sign */
+ x.d = d;
+ if (x.s.sig == 1)
+ MPFR_SET_NEG(r);
+ else
+ MPFR_SET_POS(r);
+#else /* _GMP_IEEE_FLOATS */
+ MPFR_SET_ZERO(r);
+ {
+ /* This is to get the sign of zero on non-IEEE hardware
+ Some systems support +0.0, -0.0 and unsigned zero.
+ We can't use d==+0.0 since it should be always true,
+ so we check that the memory representation of d is the
+ same than +0.0. etc */
+ /* FIXME: consider the case where +0.0 or -0.0 may have several
+ representations. */
+ double poszero = +0.0, negzero = DBL_NEG_ZERO;
+ if (memcmp(&d, &poszero, sizeof(double)) == 0)
+ MPFR_SET_POS(r);
+ else if (memcmp(&d, &negzero, sizeof(double)) == 0)
+ MPFR_SET_NEG(r);
+ else
+ MPFR_SET_POS(r);
+ }
+#endif
+ return 0; /* 0 is exact */
+ }
+ else if (MPFR_UNLIKELY(DOUBLE_ISINF(d)))
+ {
+ MPFR_SET_INF(r);
+ if (d > 0)
+ MPFR_SET_POS(r);
+ else
+ MPFR_SET_NEG(r);
+ return 0; /* infinity is exact */
+ }
+
+ /* now d is neither 0, nor NaN nor Inf */
+
+ MPFR_SAVE_EXPO_MARK (expo);
+
+ /* warning: don't use tmp=r here, even if SIZE(r) >= MPFR_LIMBS_PER_DOUBLE,
+ since PREC(r) may be different from PREC(tmp), and then both variables
+ would have same precision in the mpfr_set4 call below. */
+ MPFR_MANT(tmp) = tmpmant;
+ MPFR_PREC(tmp) = IEEE_DBL_MANT_DIG;
+
+ signd = (d < 0) ? MPFR_SIGN_NEG : MPFR_SIGN_POS;
+ d = ABS (d);
+
+ /* don't use MPFR_SET_EXP here since the exponent may be out of range */
+ MPFR_EXP(tmp) = __gmpfr_extract_double (tmpmant, d);
+
+#ifdef WANT_ASSERT
+ /* Failed assertion if the stored value is 0 (e.g., if the exponent range
+ has been reduced at the wrong moment and an underflow to 0 occurred).
+ Probably a bug in the C implementation if this happens. */
+ i = 0;
+ while (tmpmant[i] == 0)
+ {
+ i++;
+ MPFR_ASSERTN(i < MPFR_LIMBS_PER_DOUBLE);
+ }
+#endif
+
+ /* determine the index i-1 of the most significant non-zero limb
+ and the number k of zero high limbs */
+ i = MPFR_LIMBS_PER_DOUBLE;
+ MPN_NORMALIZE_NOT_ZERO(tmpmant, i);
+ k = MPFR_LIMBS_PER_DOUBLE - i;
+
+ count_leading_zeros (cnt, tmpmant[i - 1]);
+
+ if (MPFR_LIKELY(cnt != 0))
+ mpn_lshift (tmpmant + k, tmpmant, i, cnt);
+ else if (k != 0)
+ MPN_COPY (tmpmant + k, tmpmant, i);
+
+ if (MPFR_UNLIKELY(k != 0))
+ MPN_ZERO (tmpmant, k);
+
+ /* don't use MPFR_SET_EXP here since the exponent may be out of range */
+ MPFR_EXP(tmp) -= (mp_exp_t) (cnt + k * BITS_PER_MP_LIMB);
+
+ /* tmp is exact since PREC(tmp)=53 */
+ inexact = mpfr_set4 (r, tmp, rnd_mode, signd);
+
+ MPFR_SAVE_EXPO_FREE (expo);
+ return mpfr_check_range (r, inexact, rnd_mode);
+}
+
+
+
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