=================================================================== RCS file: /home/cvs/OpenXM_contrib/gmp/mpf/Attic/set_prc.c,v retrieving revision 1.1.1.2 retrieving revision 1.1.1.3 diff -u -p -r1.1.1.2 -r1.1.1.3 --- OpenXM_contrib/gmp/mpf/Attic/set_prc.c 2000/09/09 14:13:14 1.1.1.2 +++ OpenXM_contrib/gmp/mpf/Attic/set_prc.c 2003/08/25 16:06:35 1.1.1.3 @@ -1,6 +1,6 @@ /* mpf_set_prec(x) -- Change the precision of x. -Copyright (C) 1993, 1994, 1995, 2000 Free Software Foundation, Inc. +Copyright 1993, 1994, 1995, 2000, 2001 Free Software Foundation, Inc. This file is part of the GNU MP Library. @@ -22,36 +22,39 @@ MA 02111-1307, USA. */ #include "gmp.h" #include "gmp-impl.h" + +/* A full new_prec+1 limbs are always retained, even though just new_prec + would satisfy the requested precision. If size==new_prec+1 then + certainly new_prec+1 should be kept since no copying is needed in that + case. If just new_prec was kept for size>new_prec+1 it'd be a bit + inconsistent. */ + void -#if __STDC__ -mpf_set_prec (mpf_ptr x, unsigned long int prec_in_bits) -#else -mpf_set_prec (x, prec_in_bits) - mpf_ptr x; - unsigned long int prec_in_bits; -#endif +mpf_set_prec (mpf_ptr x, unsigned long int new_prec_in_bits) { - mp_size_t prec; - mp_size_t size = ABS (x->_mp_size); + mp_size_t old_prec, new_prec, new_prec_plus1; + mp_size_t size, sign; + mp_ptr xp; - prec = (MAX (53, prec_in_bits) + 2 * BITS_PER_MP_LIMB - 1)/BITS_PER_MP_LIMB; + new_prec = __GMPF_BITS_TO_PREC (new_prec_in_bits); + old_prec = PREC(x); - /* We want the most significant limbs, so move the limbs down if we are - about to truncate the value. */ - if (size > prec + 1) - { - mp_size_t offset = size - (prec + 1); - mp_ptr xp = x->_mp_d; + /* do nothing if already the right precision */ + if (new_prec == old_prec) + return; - MPN_COPY_INCR (xp, xp + offset, prec + 1); + PREC(x) = new_prec; + new_prec_plus1 = new_prec + 1; + + /* retain most significant limbs */ + sign = SIZ(x); + size = ABS (sign); + xp = PTR(x); + if (size > new_prec_plus1) + { + SIZ(x) = (sign >= 0 ? new_prec_plus1 : -new_prec_plus1); + MPN_COPY_INCR (xp, xp + size - new_prec_plus1, new_prec_plus1); } - x->_mp_d = (mp_ptr) (*_mp_reallocate_func) - (x->_mp_d, - (x->_mp_prec + 1) * BYTES_PER_MP_LIMB, (prec + 1) * BYTES_PER_MP_LIMB); - x->_mp_prec = prec; - - /* If the precision decreased, truncate the number. */ - if (size > prec + 1) - x->_mp_size = x->_mp_size >= 0 ? (prec + 1) : -(prec + 1); + PTR(x) = __GMP_REALLOCATE_FUNC_LIMBS (xp, old_prec+1, new_prec_plus1); }