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Annotation of OpenXM_contrib/gmp/mpn/generic/mul_1.c, Revision 1.1

1.1     ! maekawa     1: /* mpn_mul_1 -- Multiply a limb vector with a single limb and
        !             2:    store the product in a second limb vector.
        !             3:
        !             4: Copyright (C) 1991, 1992, 1993, 1994, 1996 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 Library General Public License as published by
        !            10: the Free Software Foundation; either version 2 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 Library General Public
        !            16: License for more details.
        !            17:
        !            18: You should have received a copy of the GNU Library 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: #include "longlong.h"
        !            26:
        !            27: mp_limb_t
        !            28: mpn_mul_1 (res_ptr, s1_ptr, s1_size, s2_limb)
        !            29:      register mp_ptr res_ptr;
        !            30:      register mp_srcptr s1_ptr;
        !            31:      mp_size_t s1_size;
        !            32:      register mp_limb_t s2_limb;
        !            33: {
        !            34:   register mp_limb_t cy_limb;
        !            35:   register mp_size_t j;
        !            36:   register mp_limb_t prod_high, prod_low;
        !            37:
        !            38:   /* The loop counter and index J goes from -S1_SIZE to -1.  This way
        !            39:      the loop becomes faster.  */
        !            40:   j = -s1_size;
        !            41:
        !            42:   /* Offset the base pointers to compensate for the negative indices.  */
        !            43:   s1_ptr -= j;
        !            44:   res_ptr -= j;
        !            45:
        !            46:   cy_limb = 0;
        !            47:   do
        !            48:     {
        !            49:       umul_ppmm (prod_high, prod_low, s1_ptr[j], s2_limb);
        !            50:
        !            51:       prod_low += cy_limb;
        !            52:       cy_limb = (prod_low < cy_limb) + prod_high;
        !            53:
        !            54:       res_ptr[j] = prod_low;
        !            55:     }
        !            56:   while (++j != 0);
        !            57:
        !            58:   return cy_limb;
        !            59: }