e554550755
for file in $(find -name \*.h ) ; do sed -e "s/#include \"gmp\.h\"/#include \"mpir.h\"/g" $file > temp ; mv temp $file ; done for file in $(find -name \*.cc) ; do sed -e "s/#include \"gmp\.h\"/#include \"mpir.h\"/g" $file > temp ; mv temp $file ; done
107 lines
2.7 KiB
C
107 lines
2.7 KiB
C
/* mpq_mul_2exp, mpq_div_2exp - multiply or divide by 2^N */
|
|
|
|
/*
|
|
Copyright 2000, 2002 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 Lesser General Public License as published by
|
|
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 Lesser General Public
|
|
License for more details.
|
|
|
|
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., 51 Franklin Street, Fifth Floor, Boston,
|
|
MA 02110-1301, USA.
|
|
*/
|
|
|
|
#include "mpir.h"
|
|
#include "gmp-impl.h"
|
|
#include "longlong.h"
|
|
|
|
|
|
/* The multiplier/divisor "n", representing 2^n, is applied by right shifting
|
|
"r" until it's odd (if it isn't already), and left shifting "l" for the
|
|
rest. */
|
|
|
|
static void
|
|
mord_2exp (mpz_ptr ldst, mpz_ptr rdst, mpz_srcptr lsrc, mpz_srcptr rsrc,
|
|
unsigned long n)
|
|
{
|
|
mp_size_t rsrc_size = SIZ(rsrc);
|
|
mp_size_t len = ABS (rsrc_size);
|
|
mp_ptr rsrc_ptr = PTR(rsrc);
|
|
mp_ptr p, rdst_ptr;
|
|
mp_limb_t plow;
|
|
|
|
p = rsrc_ptr;
|
|
plow = *p;
|
|
while (n >= GMP_NUMB_BITS && plow == 0)
|
|
{
|
|
n -= GMP_NUMB_BITS;
|
|
p++;
|
|
plow = *p;
|
|
}
|
|
|
|
/* no realloc here if rsrc==rdst, so p and rsrc_ptr remain valid */
|
|
len -= (p - rsrc_ptr);
|
|
MPZ_REALLOC (rdst, len);
|
|
rdst_ptr = PTR(rdst);
|
|
|
|
if ((plow & 1) || n == 0)
|
|
{
|
|
/* need DECR when src==dst */
|
|
if (p != rdst_ptr)
|
|
MPN_COPY_DECR (rdst_ptr, p, len);
|
|
}
|
|
else
|
|
{
|
|
unsigned long shift;
|
|
if (plow == 0)
|
|
shift = n;
|
|
else
|
|
{
|
|
count_trailing_zeros (shift, plow);
|
|
shift = MIN (shift, n);
|
|
}
|
|
mpn_rshift (rdst_ptr, p, len, shift);
|
|
len -= (rdst_ptr[len-1] == 0);
|
|
n -= shift;
|
|
}
|
|
SIZ(rdst) = (rsrc_size >= 0) ? len : -len;
|
|
|
|
if (n)
|
|
mpz_mul_2exp (ldst, lsrc, n);
|
|
else if (ldst != lsrc)
|
|
mpz_set (ldst, lsrc);
|
|
}
|
|
|
|
|
|
void
|
|
mpq_mul_2exp (mpq_ptr dst, mpq_srcptr src, unsigned long n)
|
|
{
|
|
mord_2exp (mpq_numref (dst), mpq_denref (dst),
|
|
mpq_numref (src), mpq_denref (src), n);
|
|
}
|
|
|
|
void
|
|
mpq_div_2exp (mpq_ptr dst, mpq_srcptr src, unsigned long n)
|
|
{
|
|
if (SIZ (mpq_numref(src)) == 0)
|
|
{
|
|
dst->_mp_num._mp_size = 0;
|
|
dst->_mp_den._mp_size = 1;
|
|
dst->_mp_den._mp_d[0] = 1;
|
|
return;
|
|
}
|
|
|
|
mord_2exp (mpq_denref (dst), mpq_numref (dst),
|
|
mpq_denref (src), mpq_numref (src), n);
|
|
}
|