1 /* mpf_set_prec(x) -- Change the precision of x.
3 Copyright 1993, 1994, 1995, 2000, 2001 Free Software Foundation, Inc.
5 This file is part of the GNU MP Library.
7 The GNU MP Library is free software; you can redistribute it and/or modify
8 it under the terms of the GNU Lesser General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or (at your
10 option) any later version.
12 The GNU MP Library is distributed in the hope that it will be useful, but
13 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
14 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
15 License for more details.
17 You should have received a copy of the GNU Lesser General Public License
18 along with the GNU MP Library. If not, see http://www.gnu.org/licenses/. */
24 /* A full new_prec+1 limbs are always retained, even though just new_prec
25 would satisfy the requested precision. If size==new_prec+1 then
26 certainly new_prec+1 should be kept since no copying is needed in that
27 case. If just new_prec was kept for size>new_prec+1 it'd be a bit
31 mpf_set_prec (mpf_ptr x
, mp_bitcnt_t new_prec_in_bits
)
33 mp_size_t old_prec
, new_prec
, new_prec_plus1
;
37 new_prec
= __GMPF_BITS_TO_PREC (new_prec_in_bits
);
40 /* do nothing if already the right precision */
41 if (new_prec
== old_prec
)
45 new_prec_plus1
= new_prec
+ 1;
47 /* retain most significant limbs */
51 if (size
> new_prec_plus1
)
53 SIZ(x
) = (sign
>= 0 ? new_prec_plus1
: -new_prec_plus1
);
54 MPN_COPY_INCR (xp
, xp
+ size
- new_prec_plus1
, new_prec_plus1
);
57 PTR(x
) = __GMP_REALLOCATE_FUNC_LIMBS (xp
, old_prec
+1, new_prec_plus1
);