1 /* mpfr_init2 -- initialize a floating-point number with given precision
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.
6 This file is part of the GNU MPFR Library.
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.
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.
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. */
23 #include "mpfr-impl.h"
26 mpfr_init2 (mpfr_ptr x
, mpfr_prec_t p
)
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
) );
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
);
39 MPFR_ASSERTN (mp_bits_per_limb
== GMP_NUMB_BITS
);
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
);
46 MPFR_ASSERTN( MPFR_EMAX_MAX
<= (MPFR_EXP_MAX
>> 1) );
47 MPFR_ASSERTN( MPFR_EMIN_MIN
>= -(MPFR_EXP_MAX
>> 1) );
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
);
54 xsize
= MPFR_PREC2LIMBS (p
);
55 tmp
= (mpfr_limb_ptr
) (*__gmp_allocate_func
)(MPFR_MALLOC_SIZE(xsize
));
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 */
66 #ifdef MPFR_USE_OWN_MPFR_TMP_ALLOC
67 static unsigned char mpfr_stack_tab
[8000000];
68 unsigned char *mpfr_stack
= mpfr_stack_tab
;