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Diff for /OpenXM_contrib/gmp/mpn/generic/Attic/bdivmod.c between version 1.1.1.1 and 1.1.1.3

version 1.1.1.1, 2000/01/10 15:35:23

version 1.1.1.3, 2003/08/25 16:06:20

Line 1

/* mpn/bdivmod.c: mpn_bdivmod for computing U/V mod 2^d.

Foundation, Inc.

This file is part of the GNU MP Library.

The GNU MP Library is free software; you can redistribute it and/or modify

it under the terms of the GNU Library General Public License as published by

it under the terms of the GNU Lesser General Public License as published by

the Free Software Foundation; either version 2 of the License, or (at your

the Free Software Foundation; either version 2.1 of the License, or (at your

option) any later version.

The GNU MP Library is distributed in the hope that it will be useful, but

WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY

or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public

or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public

License for more details.

You should have received a copy of the GNU Library General Public License

You should have received a copy of the GNU Lesser General Public License

along with the GNU MP Library; see the file COPYING.LIB. If not, write to

the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,

MA 02111-1307, USA. */

Line 51 MA 02111-1307, USA. */

Line 52 MA 02111-1307, USA. */

#include "gmp-impl.h"

#include "longlong.h"

mp_limb_t

#if __STDC__

mpn_bdivmod (mp_ptr qp, mp_ptr up, mp_size_t usize,

mp_srcptr vp, mp_size_t vsize, unsigned long int d)

#else

mpn_bdivmod (qp, up, usize, vp, vsize, d)

mp_ptr qp;

mp_ptr up;

mp_size_t usize;

mp_srcptr vp;

mp_size_t vsize;

unsigned long int d;

#endif

{

/* Cache for v_inv is used to make mpn_accelgcd faster. */

mp_limb_t v_inv;

static mp_limb_t previous_low_vlimb = 0;

static mp_limb_t v_inv; /* 1/V mod 2^BITS_PER_MP_LIMB. */

if (vp[0] != previous_low_vlimb) /* Cache miss; compute v_inv. */

ASSERT (usize >= 1);

{

ASSERT (vsize >= 1);

mp_limb_t v = previous_low_vlimb = vp[0];

ASSERT (usize * GMP_NUMB_BITS >= d);

mp_limb_t make_zero = 1;

ASSERT (! MPN_OVERLAP_P (up, usize, vp, vsize));

mp_limb_t two_i = 1;

ASSERT (! MPN_OVERLAP_P (qp, d/GMP_NUMB_BITS, vp, vsize));

v_inv = 0;

ASSERT (MPN_SAME_OR_INCR2_P (qp, d/GMP_NUMB_BITS, up, usize));

ASSERT_MPN (up, usize);

{

ASSERT_MPN (vp, vsize);

while ((two_i & make_zero) == 0)

two_i <<= 1, v <<= 1;

v_inv += two_i;

make_zero -= v;

}

while (make_zero);

}

/* Need faster computation for some common cases in mpn_accelgcd. */

/* 1/V mod 2^GMP_NUMB_BITS. */

modlimb_invert (v_inv, vp[0]);

/* Fast code for two cases previously used by the accel part of mpn_gcd.

(Could probably remove this now it's inlined there.) */

if (usize == 2 && vsize == 2 &&

(d == BITS_PER_MP_LIMB || d == 2*BITS_PER_MP_LIMB))

(d == GMP_NUMB_BITS || d == 2*GMP_NUMB_BITS))

{

mp_limb_t hi, lo;

mp_limb_t q = up[0] * v_inv;

mp_limb_t q = (up[0] * v_inv) & GMP_NUMB_MASK;

umul_ppmm (hi, lo, q, vp[0]);

umul_ppmm (hi, lo, q, vp[0] << GMP_NAIL_BITS);

up[0] = 0, up[1] -= hi + q*vp[1], qp[0] = q;

up[0] = 0;

if (d == 2*BITS_PER_MP_LIMB)

up[1] -= hi + q*vp[1];

q = up[1] * v_inv, up[1] = 0, qp[1] = q;

qp[0] = q;

if (d == 2*GMP_NUMB_BITS)

{

q = (up[1] * v_inv) & GMP_NUMB_MASK;

up[1] = 0;

qp[1] = q;

}

return 0;

}

/* Main loop. */

while (d >= BITS_PER_MP_LIMB)

while (d >= GMP_NUMB_BITS)

{

mp_limb_t q = up[0] * v_inv;

mp_limb_t q = (up[0] * v_inv) & GMP_NUMB_MASK;

mp_limb_t b = mpn_submul_1 (up, vp, MIN (usize, vsize), q);

if (usize > vsize)

mpn_sub_1 (up + vsize, up + vsize, usize - vsize, b);

d -= BITS_PER_MP_LIMB;

d -= GMP_NUMB_BITS;

up += 1, usize -= 1;

*qp++ = q;

}

Line 114 mpn_bdivmod (qp, up, usize, vp, vsize, d)

Line 107 mpn_bdivmod (qp, up, usize, vp, vsize, d)

{

mp_limb_t b;

mp_limb_t q = (up[0] * v_inv) & (((mp_limb_t)1<<d) - 1);

switch (q)

if (q <= 1)

{

case 0: return 0;

if (q == 0)

case 1: b = mpn_sub_n (up, up, vp, MIN (usize, vsize)); break;

return 0;

default: b = mpn_submul_1 (up, vp, MIN (usize, vsize), q); break;

else

b = mpn_sub_n (up, up, vp, MIN (usize, vsize));

}

else

b = mpn_submul_1 (up, vp, MIN (usize, vsize), q);

if (usize > vsize)

mpn_sub_1 (up + vsize, up + vsize, usize - vsize, b);

return q;

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