aa9bc17601
BMakefiles and other bits will follow. Requested by: Andrey Chernov Made world by: Chuck Robey
80 lines
2.2 KiB
C
80 lines
2.2 KiB
C
/* mpz_tdiv_r_2exp -- Divide a integer by 2**CNT and produce a remainder.
|
|
|
|
Copyright (C) 1991, 1993, 1994, 1995 Free Software 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
|
|
the Free Software Foundation; either version 2 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
|
|
License for more details.
|
|
|
|
You should have received a copy of the GNU Library 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. */
|
|
|
|
#include "gmp.h"
|
|
#include "gmp-impl.h"
|
|
|
|
void
|
|
#if __STDC__
|
|
mpz_tdiv_r_2exp (mpz_ptr res, mpz_srcptr in, unsigned long int cnt)
|
|
#else
|
|
mpz_tdiv_r_2exp (res, in, cnt)
|
|
mpz_ptr res;
|
|
mpz_srcptr in;
|
|
unsigned long int cnt;
|
|
#endif
|
|
{
|
|
mp_size_t in_size = ABS (in->_mp_size);
|
|
mp_size_t res_size;
|
|
mp_size_t limb_cnt = cnt / BITS_PER_MP_LIMB;
|
|
mp_srcptr in_ptr = in->_mp_d;
|
|
|
|
if (in_size > limb_cnt)
|
|
{
|
|
/* The input operand is (probably) greater than 2**CNT. */
|
|
mp_limb_t x;
|
|
|
|
x = in_ptr[limb_cnt] & (((mp_limb_t) 1 << cnt % BITS_PER_MP_LIMB) - 1);
|
|
if (x != 0)
|
|
{
|
|
res_size = limb_cnt + 1;
|
|
if (res->_mp_alloc < res_size)
|
|
_mpz_realloc (res, res_size);
|
|
|
|
res->_mp_d[limb_cnt] = x;
|
|
}
|
|
else
|
|
{
|
|
res_size = limb_cnt;
|
|
MPN_NORMALIZE (in_ptr, res_size);
|
|
|
|
if (res->_mp_alloc < res_size)
|
|
_mpz_realloc (res, res_size);
|
|
|
|
limb_cnt = res_size;
|
|
}
|
|
}
|
|
else
|
|
{
|
|
/* The input operand is smaller than 2**CNT. We perform a no-op,
|
|
apart from that we might need to copy IN to RES. */
|
|
res_size = in_size;
|
|
if (res->_mp_alloc < res_size)
|
|
_mpz_realloc (res, res_size);
|
|
|
|
limb_cnt = res_size;
|
|
}
|
|
|
|
if (res != in)
|
|
MPN_COPY (res->_mp_d, in->_mp_d, limb_cnt);
|
|
res->_mp_size = in->_mp_size >= 0 ? res_size : -res_size;
|
|
}
|