chromium / native_client / nacl-gcc / f80d6b9ee7f94755c697ffb7194fb01dd0c537dd / . / mpfr-2.4.1 / get_sj.c

/* mpfr_get_sj -- convert a MPFR number to a huge machine signed integer | |

Copyright 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. */ | |

#ifdef 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 | |

#if HAVE_INTTYPES_H | |

# include <inttypes.h> /* for intmax_t */ | |

#else | |

# if HAVE_STDINT_H | |

# include <stdint.h> | |

# endif | |

#endif | |

#include "mpfr-impl.h" | |

#ifdef _MPFR_H_HAVE_INTMAX_T | |

intmax_t | |

mpfr_get_sj (mpfr_srcptr f, mpfr_rnd_t rnd) | |

{ | |

intmax_t r; | |

mp_prec_t prec; | |

mpfr_t x; | |

if (!mpfr_fits_intmax_p (f, rnd)) | |

{ | |

MPFR_SET_ERANGE (); | |

return MPFR_IS_NEG (f) ? INTMAX_MIN : INTMAX_MAX; | |

} | |

if (MPFR_IS_ZERO (f)) | |

return (intmax_t) 0; | |

/* determine the precision of intmax_t */ | |

for (r = INTMAX_MIN, prec = 0; r != 0; r /= 2, prec++) | |

{ | |

} | |

/* Note: though INTMAX_MAX would have been sufficient for the conversion, | |

we chose INTMAX_MIN so that INTMAX_MIN - 1 is always representable in | |

precision prec; this is useful to detect overflows in GMP_RNDZ (will | |

be needed later). */ | |

/* Now, r = 0. */ | |

mpfr_init2 (x, prec); | |

mpfr_rint (x, f, rnd); | |

MPFR_ASSERTN (MPFR_IS_FP (x)); | |

if (MPFR_NOTZERO (x)) | |

{ | |

mp_limb_t *xp; | |

int sh, n; /* An int should be sufficient in this context. */ | |

xp = MPFR_MANT (x); | |

sh = MPFR_GET_EXP (x); | |

MPFR_ASSERTN ((mp_prec_t) sh <= prec); | |

if (INTMAX_MIN + INTMAX_MAX != 0 | |

&& MPFR_UNLIKELY ((mp_prec_t) sh == prec)) | |

{ | |

/* 2's complement and x <= INTMAX_MIN: in the case mp_limb_t | |

has the same size as intmax_t, we cannot use the code in | |

the for loop since the operations would be performed in | |

unsigned arithmetic. */ | |

MPFR_ASSERTN (MPFR_IS_NEG (x) && (mpfr_powerof2_raw (x))); | |

r = INTMAX_MIN; | |

} | |

else if (MPFR_IS_POS (x)) | |

{ | |

for (n = MPFR_LIMB_SIZE (x) - 1; n >= 0; n--) | |

{ | |

sh -= BITS_PER_MP_LIMB; | |

/* Note the concerning the casts below: | |

When sh >= 0, the cast must be performed before the shift | |

for the case sizeof(intmax_t) > sizeof(mp_limb_t). | |

When sh < 0, the cast must be performed after the shift | |

for the case sizeof(intmax_t) == sizeof(mp_limb_t), as | |

mp_limb_t is unsigned, therefore not representable as an | |

intmax_t when the MSB is 1 (this is the case here). */ | |

r += (sh >= 0 | |

? (intmax_t) xp[n] << sh | |

: (intmax_t) (xp[n] >> (-sh))); | |

} | |

} | |

else | |

{ | |

for (n = MPFR_LIMB_SIZE (x) - 1; n >= 0; n--) | |

{ | |

sh -= BITS_PER_MP_LIMB; | |

/* See above for the note concerning the casts. */ | |

r -= (sh >= 0 | |

? (intmax_t) xp[n] << sh | |

: (intmax_t) (xp[n] >> (-sh))); | |

} | |

} | |

} | |

mpfr_clear (x); | |

return r; | |

} | |

#endif |