101 lines
2.8 KiB
C
101 lines
2.8 KiB
C
/* mpn_sub_err2_n -- sub_n with two error terms
|
|
|
|
Copyright (C) 2009, David Harvey
|
|
|
|
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 THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``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 THE COPYRIGHT HOLDERS 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.
|
|
|
|
*/
|
|
|
|
#include "mpir.h"
|
|
#include "gmp-impl.h"
|
|
|
|
|
|
/*
|
|
Same as mpn_sub_err1_n, but computes both
|
|
|
|
c[1]*yp1[n-1] + ... + c[n]*yp1[0]
|
|
and c[1]*yp2[n-1] + ... + c[n]*yp2[0],
|
|
|
|
storing results at {ep,2}, {ep+2,2} respectively.
|
|
*/
|
|
mp_limb_t
|
|
mpn_sub_err2_n (mp_ptr rp, mp_srcptr up, mp_srcptr vp,
|
|
mp_ptr ep, mp_srcptr yp1, mp_srcptr yp2,
|
|
mp_size_t n, mp_limb_t cy)
|
|
{
|
|
mp_limb_t el1, eh1, el2, eh2, ul, vl, yl1, yl2, zl1, zl2, rl, sl, cy1, cy2;
|
|
|
|
ASSERT (n >= 1);
|
|
ASSERT (MPN_SAME_OR_SEPARATE_P (rp, up, n));
|
|
ASSERT (MPN_SAME_OR_SEPARATE_P (rp, vp, n));
|
|
ASSERT (!MPN_OVERLAP_P (rp, n, yp1, n));
|
|
ASSERT (!MPN_OVERLAP_P (rp, n, yp2, n));
|
|
|
|
/* FIXME: first addition into eh:el is redundant */
|
|
|
|
yp1 += n - 1;
|
|
yp2 += n - 1;
|
|
el1 = eh1 = 0;
|
|
el2 = eh2 = 0;
|
|
|
|
do
|
|
{
|
|
yl1 = *yp1--;
|
|
yl2 = *yp2--;
|
|
ul = *up++;
|
|
vl = *vp++;
|
|
|
|
/* ordinary sub_n */
|
|
SUBC_LIMB (cy1, sl, ul, vl);
|
|
SUBC_LIMB (cy2, rl, sl, cy);
|
|
cy = cy1 | cy2;
|
|
*rp++ = rl;
|
|
|
|
/* update (eh1:el1) */
|
|
zl1 = cy ? yl1 : 0;
|
|
el1 += zl1;
|
|
eh1 += el1 < zl1;
|
|
|
|
/* update (eh2:el2) */
|
|
zl2 = cy ? yl2 : 0;
|
|
el2 += zl2;
|
|
eh2 += el2 < zl2;
|
|
}
|
|
while (--n != 0);
|
|
|
|
#if GMP_NAIL_BITS != 0
|
|
eh1 = (eh1 << GMP_NAIL_BITS) + (el1 >> GMP_NUMB_BITS);
|
|
el1 &= GMP_NUMB_MASK;
|
|
eh2 = (eh2 << GMP_NAIL_BITS) + (el2 >> GMP_NUMB_BITS);
|
|
el2 &= GMP_NUMB_MASK;
|
|
#endif
|
|
|
|
ep[0] = el1;
|
|
ep[1] = eh1;
|
|
ep[2] = el2;
|
|
ep[3] = eh2;
|
|
|
|
return cy;
|
|
}
|