75 lines
2.4 KiB
C
75 lines
2.4 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(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_size_t y;
|
|
mp_bitcnt_t b1;
|
|
|
|
b1 = i*w;
|
|
y = b1/GMP_LIMB_BITS;
|
|
b1 = b1%GMP_LIMB_BITS;
|
|
|
|
mpir_butterfly_lshB(s, t, i1, i2, limbs, 0, y);
|
|
mpn_mul_2expmod_2expp1(t, t, limbs, b1);
|
|
}
|
|
|
|
void mpir_fft_radix2(mp_ptr * ii,
|
|
mp_size_t n, mp_bitcnt_t w, mp_ptr * t1, mp_ptr * t2)
|
|
{
|
|
mp_size_t i;
|
|
mp_size_t limbs = (w*n)/GMP_LIMB_BITS;
|
|
ASSERT(n!=0);
|
|
if (n == 1)
|
|
{
|
|
mpir_fft_butterfly(*t1, *t2, ii[0], ii[1], 0, limbs, w);
|
|
|
|
MP_PTR_SWAP(ii[0], *t1);
|
|
MP_PTR_SWAP(ii[1], *t2);
|
|
|
|
return;
|
|
}
|
|
|
|
for (i = 0; i < n; i++)
|
|
{
|
|
mpir_fft_butterfly(*t1, *t2, ii[i], ii[n+i], i, limbs, w);
|
|
|
|
MP_PTR_SWAP(ii[i], *t1);
|
|
MP_PTR_SWAP(ii[n+i], *t2);
|
|
}
|
|
|
|
mpir_fft_radix2(ii, n/2, 2*w, t1, t2);
|
|
mpir_fft_radix2(ii + n, n/2, 2*w, t1, t2);
|
|
}
|