1 /* mpfr_set_uj -- set a MPFR number from a huge machine unsigned integer 2 3 Copyright 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 #ifdef HAVE_CONFIG_H 24 # include "config.h" /* for a build within gmp */ 25 #endif 26 27 #define MPFR_NEED_LONGLONG_H 28 #include "mpfr-intmax.h" 29 #include "mpfr-impl.h" 30 31 #ifdef _MPFR_H_HAVE_INTMAX_T 32 33 int 34 mpfr_set_uj (mpfr_t x, uintmax_t j, mpfr_rnd_t rnd) 35 { 36 return mpfr_set_uj_2exp (x, j, 0, rnd); 37 } 38 39 int 40 mpfr_set_uj_2exp (mpfr_t x, uintmax_t j, intmax_t e, mpfr_rnd_t rnd) 41 { 42 unsigned int cnt, i; 43 mp_size_t k, len; 44 mp_limb_t limb; 45 mp_limb_t yp[sizeof(uintmax_t) / sizeof(mp_limb_t)]; 46 mpfr_t y; 47 unsigned long uintmax_bit_size = sizeof(uintmax_t) * CHAR_BIT; 48 unsigned long bpml = GMP_NUMB_BITS % uintmax_bit_size; 49 50 /* Special case */ 51 if (j == 0) 52 { 53 MPFR_SET_POS(x); 54 MPFR_SET_ZERO(x); 55 MPFR_RET(0); 56 } 57 58 MPFR_ASSERTN (sizeof(uintmax_t) % sizeof(mp_limb_t) == 0); 59 60 /* Create an auxillary var */ 61 MPFR_TMP_INIT1 (yp, y, uintmax_bit_size); 62 k = numberof (yp); 63 if (k == 1) 64 limb = yp[0] = j; 65 else 66 { 67 /* Note: either GMP_NUMB_BITS = uintmax_bit_size, then k = 1 the 68 shift j >>= bpml is never done, or GMP_NUMB_BITS < uintmax_bit_size 69 and bpml = GMP_NUMB_BITS. */ 70 for (i = 0; i < k; i++, j >>= bpml) 71 yp[i] = j; /* Only the low bits are copied */ 72 73 /* Find the first limb not equal to zero. */ 74 do 75 { 76 MPFR_ASSERTD (k > 0); 77 limb = yp[--k]; 78 } 79 while (limb == 0); 80 k++; 81 } 82 count_leading_zeros(cnt, limb); 83 len = numberof (yp) - k; 84 85 /* Normalize it: len = number of last 0 limb, k number of non-zero limbs */ 86 if (MPFR_LIKELY(cnt)) 87 mpn_lshift (yp+len, yp, k, cnt); /* Normalize the High Limb*/ 88 else if (len != 0) 89 MPN_COPY_DECR (yp+len, yp, k); /* Must use DECR */ 90 if (len != 0) 91 /* Note: when numberof(yp)==1, len is constant and null, so the compiler 92 can optimize out this code. */ 93 { 94 if (len == 1) 95 yp[0] = (mp_limb_t) 0; 96 else 97 MPN_ZERO (yp, len); /* Zeroing the last limbs */ 98 } 99 e += k * GMP_NUMB_BITS - cnt; /* Update Expo */ 100 MPFR_ASSERTD (MPFR_LIMB_MSB(yp[numberof (yp) - 1]) != 0); 101 102 /* Check expo underflow / overflow (can't use mpfr_check_range) */ 103 if (MPFR_UNLIKELY(e < __gmpfr_emin)) 104 { 105 /* The following test is necessary because in the rounding to the 106 * nearest mode, mpfr_underflow always rounds away from 0. In 107 * this rounding mode, we need to round to 0 if: 108 * _ |x| < 2^(emin-2), or 109 * _ |x| = 2^(emin-2) and the absolute value of the exact 110 * result is <= 2^(emin-2). */ 111 if (rnd == MPFR_RNDN && (e+1 < __gmpfr_emin || mpfr_powerof2_raw(y))) 112 rnd = MPFR_RNDZ; 113 return mpfr_underflow (x, rnd, MPFR_SIGN_POS); 114 } 115 if (MPFR_UNLIKELY(e > __gmpfr_emax)) 116 return mpfr_overflow (x, rnd, MPFR_SIGN_POS); 117 MPFR_SET_EXP (y, e); 118 119 /* Final: set x to y (rounding if necessary) */ 120 return mpfr_set (x, y, rnd); 121 } 122 123 #endif 124