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Annotation of OpenXM_contrib/gmp/mpf/integer.c, Revision 1.1.1.1

1.1       maekawa     1: /* mpf_trunc, mpf_floor, mpf_ceil -- Assign a float from another float while
                      2:    rounding it to an integer.
                      3:
                      4: Copyright (C) 1997, 1998, 2000 Free Software Foundation, Inc.
                      5:
                      6: This file is part of the GNU MP Library.
                      7:
                      8: The GNU MP 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 2.1 of the License, or (at your
                     11: option) any later version.
                     12:
                     13: The GNU MP 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 MP Library; see the file COPYING.LIB.  If not, write to
                     20: the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
                     21: MA 02111-1307, USA. */
                     22:
                     23: #include "gmp.h"
                     24: #include "gmp-impl.h"
                     25:
                     26:
                     27: #if defined (OPERATION_floor)
                     28: #define _MPF_FLOOR_OR_CEIL
                     29: #define FUNC_NAME mpf_floor
                     30: #define MPF_FLOOR 1
                     31: #define MPF_CEIL 0
                     32:
                     33: #elif defined (OPERATION_ceil)
                     34: #define _MPF_FLOOR_OR_CEIL
                     35: #define FUNC_NAME mpf_ceil
                     36: #define MPF_CEIL 1
                     37: #define MPF_FLOOR 0
                     38:
                     39: #elif defined (OPERATION_trunc)
                     40: #define FUNC_NAME mpf_trunc
                     41:
                     42: #else
                     43: Error, error, unrecognised OPERATION
                     44: #endif
                     45:
                     46:
                     47: #ifdef _MPF_FLOOR_OR_CEIL
                     48: static int
                     49: #if __STDC__
                     50: mpn_zero_p (mp_ptr p, mp_size_t n)
                     51: #else
                     52: mpn_zero_p (p, n)
                     53:      mp_ptr p;
                     54:      mp_size_t n;
                     55: #endif
                     56: {
                     57:   mp_size_t i;
                     58:
                     59:   for (i = 0; i < n; i++)
                     60:     {
                     61:       if (p[i] != 0)
                     62:        return 0;
                     63:     }
                     64:
                     65:   return 1;
                     66: }
                     67: #endif
                     68:
                     69: void
                     70: #if __STDC__
                     71: FUNC_NAME (mpf_ptr r, mpf_srcptr u)
                     72: #else
                     73: FUNC_NAME (r, u)
                     74:      mpf_ptr r;
                     75:      mpf_srcptr u;
                     76: #endif
                     77: {
                     78:   mp_ptr rp, up;
                     79:   mp_size_t size, asize;
                     80:   mp_size_t prec;
                     81:   mp_size_t ignored_n;
                     82:   mp_exp_t exp;
                     83:
                     84:   size = u->_mp_size;
                     85:   rp = r->_mp_d;
                     86:   exp = u->_mp_exp;
                     87:
                     88:   /* Single out the case where |u| < 1.  */
                     89:   if (exp <= 0)
                     90:     {
                     91: #ifdef _MPF_FLOOR_OR_CEIL
                     92:       if ((MPF_FLOOR && size < 0) || (MPF_CEIL && size >= 0))
                     93:        {
                     94:          rp[0] = 1;
                     95:          r->_mp_size = MPF_FLOOR ? -1 : 1;
                     96:          r->_mp_exp = 1;
                     97:          return;
                     98:        }
                     99: #endif
                    100:       r->_mp_size = 0;
                    101:       return;
                    102:     }
                    103:
                    104:   prec = r->_mp_prec /* + 1 */;
                    105:   asize = ABS (size);
                    106:
                    107: #ifdef _MPF_FLOOR_OR_CEIL
                    108:   ignored_n = 0;
                    109: #endif
                    110:   up = u->_mp_d;
                    111:
                    112:   if (asize > prec)
                    113:     {
                    114: #ifdef _MPF_FLOOR_OR_CEIL
                    115:       ignored_n = asize - prec;
                    116: #endif
                    117:       up += asize - prec;
                    118:       asize = prec;
                    119:     }
                    120:
                    121:   if (asize > exp)
                    122:     {
                    123:       long diff = asize - exp;
                    124: #ifdef _MPF_FLOOR_OR_CEIL
                    125:       ignored_n += diff;
                    126: #endif
                    127:       up += diff;
                    128:       asize = exp;
                    129:     }
                    130:
                    131: #ifdef _MPF_FLOOR_OR_CEIL
                    132:   if (((MPF_FLOOR && size < 0) || (MPF_CEIL && size >= 0))
                    133:       && ! mpn_zero_p (up - ignored_n, ignored_n))
                    134:     {
                    135:       mp_limb_t cy;
                    136:       cy = mpn_add_1 (rp, up, asize, (mp_limb_t) 1);
                    137:       if (cy != 0)
                    138:        {
                    139:          rp[asize++] = cy;
                    140:          exp++;
                    141:        }
                    142:     }
                    143:   else
                    144: #endif
                    145:   MPN_COPY_INCR (rp, up, asize);
                    146:
                    147:   r->_mp_exp = exp;
                    148:   r->_mp_size = size >= 0 ? asize : -asize;
                    149: }