117 lines
3.6 KiB
C
117 lines
3.6 KiB
C
/*
|
|
|
|
Copyright 2009, 2011 William Hart. All rights reserved.
|
|
|
|
Redistribution and use in source and binary forms, with or without modification, are
|
|
permitted provided that the following conditions are met:
|
|
|
|
1. Redistributions of source code must retain the above copyright notice, this list of
|
|
conditions and the following disclaimer.
|
|
|
|
2. Redistributions in binary form must reproduce the above copyright notice, this list
|
|
of conditions and the following disclaimer in the documentation and/or other materials
|
|
provided with the distribution.
|
|
|
|
THIS SOFTWARE IS PROVIDED BY William Hart ``AS IS'' AND ANY EXPRESS OR IMPLIED
|
|
WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
|
|
FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL William Hart OR
|
|
CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
|
|
CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
|
|
SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
|
|
ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
|
|
NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
|
|
ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
|
|
|
|
The views and conclusions contained in the software and documentation are those of the
|
|
authors and should not be interpreted as representing official policies, either expressed
|
|
or implied, of William Hart.
|
|
|
|
*/
|
|
|
|
#include "mpir.h"
|
|
#include "gmp-impl.h"
|
|
|
|
void mpir_fft_butterfly_sqrt2(mp_ptr s, mp_ptr t,
|
|
mp_ptr i1, mp_ptr i2, mp_size_t i,
|
|
mp_size_t limbs, mp_bitcnt_t w, mp_ptr temp)
|
|
{
|
|
mp_bitcnt_t wn = limbs*GMP_LIMB_BITS;
|
|
mp_limb_t cy = 0;
|
|
mp_size_t j = i/2, k = w/2;
|
|
mp_size_t y;
|
|
mp_bitcnt_t b1;
|
|
int negate = 0;
|
|
|
|
b1 = j + wn/4 + i*k;
|
|
if (b1 >= wn)
|
|
{
|
|
negate = 1;
|
|
b1 -= wn;
|
|
}
|
|
y = b1/GMP_LIMB_BITS;
|
|
b1 = b1%GMP_LIMB_BITS;
|
|
|
|
/* sumdiff and multiply by 2^{j + wn/4 + i*k} */
|
|
mpir_butterfly_lshB(s, t, i1, i2, limbs, 0, y);
|
|
mpn_mul_2expmod_2expp1(t, t, limbs, b1);
|
|
|
|
/* multiply by 2^{wn/2} */
|
|
y = limbs/2;
|
|
|
|
mpn_copyi(temp + y, t, limbs - y);
|
|
temp[limbs] = 0;
|
|
if (y) cy = mpn_neg_n(temp, t + limbs - y, y);
|
|
mpn_addmod_2expp1_1(temp + y, limbs - y, -t[limbs]);
|
|
mpn_sub_1(temp + y, temp + y, limbs - y + 1, cy);
|
|
|
|
/* shift by an additional half limb (rare) */
|
|
if (limbs & 1)
|
|
mpn_mul_2expmod_2expp1(temp, temp, limbs, GMP_LIMB_BITS/2);
|
|
|
|
/* subtract */
|
|
if (negate)
|
|
mpn_sub_n(t, t, temp, limbs + 1);
|
|
else
|
|
mpn_sub_n(t, temp, t, limbs + 1);
|
|
}
|
|
|
|
void mpir_fft_trunc_sqrt2(mp_ptr * ii, mp_size_t n, mp_bitcnt_t w,
|
|
mp_ptr * t1, mp_ptr * t2, mp_ptr * temp, mp_size_t trunc)
|
|
{
|
|
mp_size_t i;
|
|
mp_size_t limbs = (w*n)/GMP_LIMB_BITS;
|
|
|
|
if ((w & 1) == 0)
|
|
{
|
|
mpir_fft_trunc(ii, 2*n, w/2, t1, t2, trunc);
|
|
return;
|
|
}
|
|
|
|
for (i = 0; i < trunc - 2*n; i++)
|
|
{
|
|
mpir_fft_butterfly(*t1, *t2, ii[i], ii[2*n+i], i/2, limbs, w);
|
|
|
|
MP_PTR_SWAP(ii[i], *t1);
|
|
MP_PTR_SWAP(ii[i+2*n], *t2);
|
|
|
|
i++;
|
|
|
|
mpir_fft_butterfly_sqrt2(*t1, *t2, ii[i], ii[2*n+i], i, limbs, w, *temp);
|
|
|
|
MP_PTR_SWAP(ii[i], *t1);
|
|
MP_PTR_SWAP(ii[2*n+i], *t2);
|
|
}
|
|
|
|
for (i = trunc - 2*n; i < 2*n; i++)
|
|
{
|
|
mpir_fft_adjust(ii[i+2*n], ii[i], i/2, limbs, w);
|
|
|
|
i++;
|
|
|
|
mpir_fft_adjust_sqrt2(ii[i+2*n], ii[i], i, limbs, w, *temp);
|
|
}
|
|
|
|
mpir_fft_radix2(ii, n, w, t1, t2);
|
|
mpir_fft_trunc1(ii + 2*n, n, w, t1, t2, trunc - 2*n);
|
|
}
|