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Annotation of OpenXM_contrib/gmp/mpn/generic/pre_mod_1.c, Revision 1.1.1.1

1.1       maekawa     1: /* mpn_preinv_mod_1 (dividend_ptr, dividend_size, divisor_limb,
                      2:                       divisor_limb_inverted) --
                      3:    Divide (DIVIDEND_PTR,,DIVIDEND_SIZE) by the normalized DIVISOR_LIMB.
                      4:    DIVISOR_LIMB_INVERTED should be 2^(2*BITS_PER_MP_LIMB) / DIVISOR_LIMB +
                      5:    - 2^BITS_PER_MP_LIMB.
                      6:    Return the single-limb remainder.
                      7:
                      8: Copyright (C) 1991, 1993, 1994, Free Software Foundation, Inc.
                      9:
                     10: This file is part of the GNU MP Library.
                     11:
                     12: The GNU MP Library is free software; you can redistribute it and/or modify
                     13: it under the terms of the GNU Library General Public License as published by
                     14: the Free Software Foundation; either version 2 of the License, or (at your
                     15: option) any later version.
                     16:
                     17: The GNU MP Library is distributed in the hope that it will be useful, but
                     18: WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
                     19: or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Library General Public
                     20: License for more details.
                     21:
                     22: You should have received a copy of the GNU Library General Public License
                     23: along with the GNU MP Library; see the file COPYING.LIB.  If not, write to
                     24: the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
                     25: MA 02111-1307, USA. */
                     26:
                     27: #include "gmp.h"
                     28: #include "gmp-impl.h"
                     29: #include "longlong.h"
                     30:
                     31: #ifndef UMUL_TIME
                     32: #define UMUL_TIME 1
                     33: #endif
                     34:
                     35: #ifndef UDIV_TIME
                     36: #define UDIV_TIME UMUL_TIME
                     37: #endif
                     38:
                     39: mp_limb_t
                     40: #if __STDC__
                     41: mpn_preinv_mod_1 (mp_srcptr dividend_ptr, mp_size_t dividend_size,
                     42:                  mp_limb_t divisor_limb, mp_limb_t divisor_limb_inverted)
                     43: #else
                     44: mpn_preinv_mod_1 (dividend_ptr, dividend_size, divisor_limb, divisor_limb_inverted)
                     45:      mp_srcptr dividend_ptr;
                     46:      mp_size_t dividend_size;
                     47:      mp_limb_t divisor_limb;
                     48:      mp_limb_t divisor_limb_inverted;
                     49: #endif
                     50: {
                     51:   mp_size_t i;
                     52:   mp_limb_t n0, r;
                     53:   int dummy;
                     54:
                     55:   i = dividend_size - 1;
                     56:   r = dividend_ptr[i];
                     57:
                     58:   if (r >= divisor_limb)
                     59:     r = 0;
                     60:   else
                     61:     i--;
                     62:
                     63:   for (; i >= 0; i--)
                     64:     {
                     65:       n0 = dividend_ptr[i];
                     66:       udiv_qrnnd_preinv (dummy, r, r, n0, divisor_limb, divisor_limb_inverted);
                     67:     }
                     68:   return r;
                     69: }