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Annotation of OpenXM_contrib/gmp/mpfr/set_f.c, Revision 1.1.1.1

1.1       maekawa     1: /* mpfr_set_f -- set a MPFR number from a GNU MPF number
                      2:
                      3: Copyright (C) 1999-2000 PolKA project, Inria Lorraine and Loria
                      4:
                      5: This file is part of the MPFR Library.
                      6:
                      7: The MPFR Library is free software; you can redistribute it and/or modify
                      8: it under the terms of the GNU Library General Public License as published by
                      9: the Free Software Foundation; either version 2 of the License, or (at your
                     10: option) any later version.
                     11:
                     12: The MPFR 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 Library General Public
                     15: License for more details.
                     16:
                     17: You should have received a copy of the GNU Library General Public License
                     18: along with the MPFR Library; see the file COPYING.LIB.  If not, write to
                     19: the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
                     20: MA 02111-1307, USA. */
                     21:
                     22: #include <stdio.h>
                     23: #include "gmp.h"
                     24: #include "gmp-impl.h"
                     25: #include "longlong.h"
                     26: #include "mpfr.h"
                     27:
                     28: void
                     29: #if __STDC__
                     30: mpfr_set_f(mpfr_ptr y, mpf_srcptr x, char rnd_mode)
                     31: #else
                     32: mpfr_set_f(y, x, rnd_mode)
                     33:      mpfr_ptr y;
                     34:      mpf_srcptr x;
                     35:      char rnd_mode;
                     36: #endif
                     37: {
                     38:   mp_limb_t *my, *mx, *tmp; unsigned long cnt, sx, sy;
                     39:   TMP_DECL(marker);
                     40:
                     41:   sx = ABS(SIZ(x)); sy = ABSSIZE(y);
                     42:   my = MANT(y); mx = MANT(x);
                     43:
                     44:   if (sx==0) { /* x is zero */
                     45:     SET_ZERO(y); return;
                     46:   }
                     47:
                     48:   count_leading_zeros(cnt, mx[sx - 1]);
                     49:
                     50:   if (SIZ(x)*SIGN(y)<0) CHANGE_SIGN(y);
                     51:
                     52:   if (sy < sx)
                     53:     {
                     54:       unsigned long xprec = sx * BITS_PER_MP_LIMB;
                     55:
                     56:       tmp = (mp_limb_t*) TMP_ALLOC(xprec);
                     57:       if (cnt) mpn_lshift(tmp, mx, sx, cnt);
                     58:       else MPN_COPY(tmp, mx, sx);
                     59:       mpfr_round_raw(my, tmp, xprec, (SIZ(x)<0), PREC(y), rnd_mode);
                     60:     }
                     61:   else
                     62:     {
                     63:       if (cnt) mpn_lshift(my + sy - sx, mx, sx, cnt);
                     64:       else MPN_COPY(my + sy - sx, mx, sy);
                     65:       MPN_ZERO(my, sy - sx);
                     66:       /* no rounding necessary, since y has a larger mantissa */
                     67:     }
                     68:
                     69:   EXP(y) = EXP(x) * BITS_PER_MP_LIMB - cnt;
                     70:
                     71:   TMP_FREE(marker);
                     72: }