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      1 /* mpz_set_d(integer, val) -- Assign INTEGER with a double value VAL.
      2 
      3 Copyright 1995, 1996, 2000-2003, 2006, 2015 Free Software Foundation, Inc.
      4 
      5 This file is part of the GNU MP Library.
      6 
      7 The GNU MP Library is free software; you can redistribute it and/or modify
      8 it under the terms of either:
      9 
     10   * the GNU Lesser General Public License as published by the Free
     11     Software Foundation; either version 3 of the License, or (at your
     12     option) any later version.
     13 
     14 or
     15 
     16   * the GNU General Public License as published by the Free Software
     17     Foundation; either version 2 of the License, or (at your option) any
     18     later version.
     19 
     20 or both in parallel, as here.
     21 
     22 The GNU MP Library is distributed in the hope that it will be useful, but
     23 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
     24 or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
     25 for more details.
     26 
     27 You should have received copies of the GNU General Public License and the
     28 GNU Lesser General Public License along with the GNU MP Library.  If not,
     29 see https://www.gnu.org/licenses/.  */
     30 
     31 #include "config.h"
     32 
     33 #if HAVE_FLOAT_H
     34 #include <float.h>  /* for DBL_MAX */
     35 #endif
     36 
     37 #include "gmp-impl.h"
     38 
     39 
     40 /* We used to have a special case for d < MP_BASE_AS_DOUBLE, just casting
     41    double -> limb.  Unfortunately gcc 3.3 on powerpc970-apple-darwin6.8.5
     42    got this wrong.  (It assumed __fixunsdfdi returned its result in a single
     43    64-bit register, where instead that function followed the calling
     44    conventions and gave the result in two parts r3 and r4.)  Hence the use
     45    of __gmp_extract_double in all cases.  */
     46 
     47 void
     48 mpz_set_d (mpz_ptr r, double d)
     49 {
     50   int negative;
     51   mp_limb_t tp[LIMBS_PER_DOUBLE];
     52   mp_ptr rp;
     53   mp_size_t rn;
     54 
     55   DOUBLE_NAN_INF_ACTION (d,
     56 			 __gmp_invalid_operation (),
     57 			 __gmp_invalid_operation ());
     58 
     59   negative = d < 0;
     60   d = ABS (d);
     61 
     62   rn = __gmp_extract_double (tp, d);
     63 
     64   if (rn <= 0)
     65     rn = 0;
     66 
     67   rp = MPZ_NEWALLOC (r, rn);
     68 
     69   switch (rn)
     70     {
     71     default:
     72       MPN_ZERO (rp, rn - LIMBS_PER_DOUBLE);
     73       rp += rn - LIMBS_PER_DOUBLE;
     74       /* fall through */
     75 #if LIMBS_PER_DOUBLE == 2
     76     case 2:
     77       rp[1] = tp[1], rp[0] = tp[0];
     78       break;
     79     case 1:
     80       rp[0] = tp[1];
     81       break;
     82 #endif
     83 #if LIMBS_PER_DOUBLE == 3
     84     case 3:
     85       rp[2] = tp[2], rp[1] = tp[1], rp[0] = tp[0];
     86       break;
     87     case 2:
     88       rp[1] = tp[2], rp[0] = tp[1];
     89       break;
     90     case 1:
     91       rp[0] = tp[2];
     92       break;
     93 #endif
     94 #if LIMBS_PER_DOUBLE == 4
     95     case 4:
     96       rp[3] = tp[3], rp[2] = tp[2], rp[1] = tp[1], rp[0] = tp[0];
     97       break;
     98     case 3:
     99       rp[2] = tp[3], rp[1] = tp[2], rp[0] = tp[1];
    100       break;
    101     case 2:
    102       rp[1] = tp[3], rp[0] = tp[2];
    103       break;
    104     case 1:
    105       rp[0] = tp[3];
    106       break;
    107 #endif
    108     case 0:
    109       break;
    110     }
    111 
    112   SIZ(r) = negative ? -rn : rn;
    113 }
    114