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

1.1     ! maekawa     1: /* mpn_sqr_basecase -- Internal routine to square two natural numbers
        !             2:    of length m and n.
        !             3:
        !             4:    THIS IS AN INTERNAL FUNCTION WITH A MUTABLE INTERFACE.  IT IS ONLY
        !             5:    SAFE TO REACH THIS FUNCTION THROUGH DOCUMENTED INTERFACES.
        !             6:
        !             7:
        !             8: Copyright (C) 1991, 1992, 1993, 1994, 1996, 1997, 2000 Free Software
        !             9: Foundation, Inc.
        !            10:
        !            11: This file is part of the GNU MP Library.
        !            12:
        !            13: The GNU MP Library is free software; you can redistribute it and/or modify
        !            14: it under the terms of the GNU Lesser General Public License as published by
        !            15: the Free Software Foundation; either version 2.1 of the License, or (at your
        !            16: option) any later version.
        !            17:
        !            18: The GNU MP Library is distributed in the hope that it will be useful, but
        !            19: WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
        !            20: or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
        !            21: License for more details.
        !            22:
        !            23: You should have received a copy of the GNU Lesser General Public License
        !            24: along with the GNU MP Library; see the file COPYING.LIB.  If not, write to
        !            25: the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
        !            26: MA 02111-1307, USA. */
        !            27:
        !            28: #include "gmp.h"
        !            29: #include "gmp-impl.h"
        !            30: #include "longlong.h"
        !            31:
        !            32: void
        !            33: #if __STDC__
        !            34: mpn_sqr_basecase (mp_ptr prodp, mp_srcptr up, mp_size_t n)
        !            35: #else
        !            36: mpn_sqr_basecase (prodp, up, n)
        !            37:      mp_ptr prodp;
        !            38:      mp_srcptr up;
        !            39:      mp_size_t n;
        !            40: #endif
        !            41: {
        !            42:   mp_size_t i;
        !            43:
        !            44:   {
        !            45:     /* N.B.!  We need the superfluous indirection through argh to work around
        !            46:        a reloader bug in GCC 2.7.*.  */
        !            47:     mp_limb_t x;
        !            48:     mp_limb_t argh;
        !            49:     x = up[0];
        !            50:     umul_ppmm (argh, prodp[0], x, x);
        !            51:     prodp[1] = argh;
        !            52:   }
        !            53:   if (n > 1)
        !            54:     {
        !            55:       mp_limb_t tarr[2 * KARATSUBA_SQR_THRESHOLD];
        !            56:       mp_ptr tp = tarr;
        !            57:       mp_limb_t cy;
        !            58:
        !            59:       /* must fit 2*n limbs in tarr */
        !            60:       ASSERT (n <= KARATSUBA_SQR_THRESHOLD);
        !            61:
        !            62:       cy = mpn_mul_1 (tp, up + 1, n - 1, up[0]);
        !            63:       tp[n - 1] = cy;
        !            64:       for (i = 2; i < n; i++)
        !            65:        {
        !            66:          mp_limb_t cy;
        !            67:          cy = mpn_addmul_1 (tp + 2 * i - 2, up + i, n - i, up[i - 1]);
        !            68:          tp[n + i - 2] = cy;
        !            69:        }
        !            70:       for (i = 1; i < n; i++)
        !            71:        {
        !            72:          mp_limb_t x;
        !            73:          x = up[i];
        !            74:          umul_ppmm (prodp[2 * i + 1], prodp[2 * i], x, x);
        !            75:        }
        !            76:       {
        !            77:        mp_limb_t cy;
        !            78:        cy = mpn_lshift (tp, tp, 2 * n - 2, 1);
        !            79:        cy += mpn_add_n (prodp + 1, prodp + 1, tp, 2 * n - 2);
        !            80:        prodp[2 * n - 1] += cy;
        !            81:       }
        !            82:     }
        !            83: }