1 /* mpfr_init2 -- initialize a floating-point number with given precision 2 3 Copyright 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013 Free Software Foundation, Inc. 4 Contributed by the AriC and Caramel 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 3 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.LESSER. If not, see 20 http://www.gnu.org/licenses/ or write to the Free Software Foundation, Inc., 21 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA. */ 22 23 #include "mpfr-impl.h" 24 25 void 26 mpfr_init2 (mpfr_ptr x, mpfr_prec_t p) 27 { 28 mp_size_t xsize; 29 mpfr_limb_ptr tmp; 30 31 /* Check if we can represent the number of limbs 32 * associated to the maximum of mpfr_prec_t*/ 33 MPFR_ASSERTN( MP_SIZE_T_MAX >= (MPFR_PREC_MAX/BYTES_PER_MP_LIMB) ); 34 35 /* Check for correct GMP_NUMB_BITS and BYTES_PER_MP_LIMB */ 36 MPFR_ASSERTN( GMP_NUMB_BITS == BYTES_PER_MP_LIMB * CHAR_BIT 37 && sizeof(mp_limb_t) == BYTES_PER_MP_LIMB ); 38 39 MPFR_ASSERTN (mp_bits_per_limb == GMP_NUMB_BITS); 40 41 /* Check for correct EXP NAN, ZERO & INF in both mpfr.h and mpfr-impl.h */ 42 MPFR_ASSERTN( __MPFR_EXP_NAN == MPFR_EXP_NAN ); 43 MPFR_ASSERTN( __MPFR_EXP_ZERO == MPFR_EXP_ZERO ); 44 MPFR_ASSERTN( __MPFR_EXP_INF == MPFR_EXP_INF ); 45 46 MPFR_ASSERTN( MPFR_EMAX_MAX <= (MPFR_EXP_MAX >> 1) ); 47 MPFR_ASSERTN( MPFR_EMIN_MIN >= -(MPFR_EXP_MAX >> 1) ); 48 49 /* p=1 is not allowed since the rounding to nearest even rule requires at 50 least two bits of mantissa: the neighbours of 3/2 are 1*2^0 and 1*2^1, 51 which both have an odd mantissa */ 52 MPFR_ASSERTN(p >= MPFR_PREC_MIN && p <= MPFR_PREC_MAX); 53 54 xsize = MPFR_PREC2LIMBS (p); 55 tmp = (mpfr_limb_ptr) (*__gmp_allocate_func)(MPFR_MALLOC_SIZE(xsize)); 56 57 MPFR_PREC(x) = p; /* Set prec */ 58 MPFR_EXP (x) = MPFR_EXP_INVALID; /* make sure that the exp field has a 59 valid value in the C point of view */ 60 MPFR_SET_POS(x); /* Set a sign */ 61 MPFR_SET_MANT_PTR(x, tmp); /* Set Mantissa ptr */ 62 MPFR_SET_ALLOC_SIZE(x, xsize); /* Fix alloc size of Mantissa */ 63 MPFR_SET_NAN(x); /* initializes to NaN */ 64 } 65 66 #ifdef MPFR_USE_OWN_MPFR_TMP_ALLOC 67 static unsigned char mpfr_stack_tab[8000000]; 68 unsigned char *mpfr_stack = mpfr_stack_tab; 69 #endif 70