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| 1 /* mpfr_fits_*_p -- test whether an mpfr fits a C unsigned type. | |
| 2 | |
| 3 Copyright 2003, 2004, 2005, 2006, 2007, 2008, 2009 Free Software Foundation, Inc
. | |
| 4 Contributed by the Arenaire and Cacao projects, INRIA. | |
| 5 | |
| 6 This file is part of the GNU MPFR Library. | |
| 7 | |
| 8 The GNU MPFR Library is free software; you can redistribute it and/or modify | |
| 9 it under the terms of the GNU Lesser General Public License as published by | |
| 10 the Free Software Foundation; either version 2.1 of the License, or (at your | |
| 11 option) any later version. | |
| 12 | |
| 13 The GNU MPFR Library is distributed in the hope that it will be useful, but | |
| 14 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY | |
| 15 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public | |
| 16 License for more details. | |
| 17 | |
| 18 You should have received a copy of the GNU Lesser General Public License | |
| 19 along with the GNU MPFR Library; see the file COPYING.LIB. If not, write to | |
| 20 the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, | |
| 21 MA 02110-1301, USA. */ | |
| 22 | |
| 23 #include "mpfr-impl.h" | |
| 24 | |
| 25 int | |
| 26 FUNCTION (mpfr_srcptr f, mp_rnd_t rnd) | |
| 27 { | |
| 28 mp_exp_t exp; | |
| 29 mp_prec_t prec; | |
| 30 TYPE s; | |
| 31 mpfr_t x; | |
| 32 int res; | |
| 33 | |
| 34 if (MPFR_UNLIKELY (MPFR_IS_SINGULAR (f))) | |
| 35 /* Zero always fit */ | |
| 36 return MPFR_IS_ZERO (f) ? 1 : 0; | |
| 37 else if (MPFR_IS_NEG (f)) | |
| 38 /* Negative numbers doesn't fit */ | |
| 39 return 0; | |
| 40 /* now it fits if | |
| 41 (a) f <= MAXIMUM | |
| 42 (b) round(f, prec(slong), rnd) <= MAXIMUM */ | |
| 43 | |
| 44 exp = MPFR_GET_EXP (f); | |
| 45 if (exp < 1) | |
| 46 return 1; /* |f| < 1: always fits */ | |
| 47 | |
| 48 /* first compute prec(MAXIMUM) */ | |
| 49 for (s = MAXIMUM, prec = 0; s != 0; s /= 2, prec ++); | |
| 50 | |
| 51 /* MAXIMUM needs prec bits, i.e. 2^(prec-1) <= |MAXIMUM| < 2^prec */ | |
| 52 | |
| 53 /* if exp < prec - 1, then f < 2^(prec-1) < |MAXIMUM| */ | |
| 54 if ((mpfr_prec_t) exp < prec - 1) | |
| 55 return 1; | |
| 56 | |
| 57 /* if exp > prec + 1, then f >= 2^prec > MAXIMUM */ | |
| 58 if ((mpfr_prec_t) exp > prec + 1) | |
| 59 return 0; | |
| 60 | |
| 61 /* remains cases exp = prec-1 to prec+1 */ | |
| 62 | |
| 63 /* hard case: first round to prec bits, then check */ | |
| 64 mpfr_init2 (x, prec); | |
| 65 mpfr_set (x, f, rnd); | |
| 66 res = mpfr_cmp_ui (x, MAXIMUM) <= 0; | |
| 67 mpfr_clear (x); | |
| 68 | |
| 69 return res; | |
| 70 } | |
| 71 | |
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Chromium Code Reviews
Issue 3050029:
[gcc] GCC 4.5.0=>4.5.1 (Closed)
Base URL: ssh://git@gitrw.chromium.org:9222/nacl-toolchain.git