aa9bc17601
BMakefiles and other bits will follow. Requested by: Andrey Chernov Made world by: Chuck Robey
130 lines
3.4 KiB
C
130 lines
3.4 KiB
C
/* mpz_pow_ui(res, base, exp) -- Set RES to BASE**EXP.
|
|
|
|
Copyright (C) 1991, 1993, 1994, 1996 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. */
|
|
|
|
#ifdef BERKELEY_MP
|
|
#include "mp.h"
|
|
#endif
|
|
#include "gmp.h"
|
|
#include "gmp-impl.h"
|
|
#include "longlong.h"
|
|
|
|
#ifndef BERKELEY_MP
|
|
void
|
|
#if __STDC__
|
|
mpz_pow_ui (mpz_ptr r, mpz_srcptr b, unsigned long int e)
|
|
#else
|
|
mpz_pow_ui (r, b, e)
|
|
mpz_ptr r;
|
|
mpz_srcptr b;
|
|
unsigned long int e;
|
|
#endif
|
|
#else /* BERKELEY_MP */
|
|
void
|
|
#if __STDC__
|
|
rpow (const MINT *b, signed short int e, MINT *r)
|
|
#else
|
|
rpow (b, e, r)
|
|
const MINT *b;
|
|
signed short int e;
|
|
MINT *r;
|
|
#endif
|
|
#endif /* BERKELEY_MP */
|
|
{
|
|
mp_ptr rp, bp, tp, xp;
|
|
mp_size_t rsize, bsize;
|
|
int cnt, i;
|
|
mp_limb_t blimb;
|
|
TMP_DECL (marker);
|
|
|
|
bsize = ABS (b->_mp_size);
|
|
|
|
/* Single out cases that give result == 0 or 1. These tests are here
|
|
to simplify the general code below, not to optimize. */
|
|
if (e == 0)
|
|
{
|
|
r->_mp_d[0] = 1;
|
|
r->_mp_size = 1;
|
|
return;
|
|
}
|
|
if (bsize == 0
|
|
#ifdef BERKELEY_MP
|
|
|| e < 0
|
|
#endif
|
|
)
|
|
{
|
|
r->_mp_size = 0;
|
|
return;
|
|
}
|
|
|
|
bp = b->_mp_d;
|
|
|
|
blimb = bp[bsize - 1];
|
|
if (bsize == 1 && blimb < 0x100)
|
|
{
|
|
/* Estimate space requirements accurately. Using the code from the
|
|
`else' path would over-estimate space requirements wildly. */
|
|
float lb = __mp_bases[blimb].chars_per_bit_exactly;
|
|
rsize = 2 + ((mp_size_t) (e / lb) / BITS_PER_MP_LIMB);
|
|
}
|
|
else
|
|
{
|
|
/* Over-estimate space requirements somewhat. */
|
|
count_leading_zeros (cnt, blimb);
|
|
rsize = bsize * e - cnt * e / BITS_PER_MP_LIMB + 1;
|
|
}
|
|
|
|
TMP_MARK (marker);
|
|
|
|
/* The two areas are used to alternatingly hold the input and recieve the
|
|
product for mpn_mul. (This scheme is used to fulfill the requirements
|
|
of mpn_mul; that the product space may not be the same as any of the
|
|
input operands.) */
|
|
rp = (mp_ptr) TMP_ALLOC (rsize * BYTES_PER_MP_LIMB);
|
|
tp = (mp_ptr) TMP_ALLOC (rsize * BYTES_PER_MP_LIMB);
|
|
|
|
MPN_COPY (rp, bp, bsize);
|
|
rsize = bsize;
|
|
count_leading_zeros (cnt, e);
|
|
|
|
for (i = BITS_PER_MP_LIMB - cnt - 2; i >= 0; i--)
|
|
{
|
|
mpn_mul_n (tp, rp, rp, rsize);
|
|
rsize = 2 * rsize;
|
|
rsize -= tp[rsize - 1] == 0;
|
|
xp = tp; tp = rp; rp = xp;
|
|
|
|
if ((e & ((mp_limb_t) 1 << i)) != 0)
|
|
{
|
|
rsize = rsize + bsize - (mpn_mul (tp, rp, rsize, bp, bsize) == 0);
|
|
xp = tp; tp = rp; rp = xp;
|
|
}
|
|
}
|
|
|
|
/* Now then we know the exact space requirements, reallocate if
|
|
necessary. */
|
|
if (r->_mp_alloc < rsize)
|
|
_mpz_realloc (r, rsize);
|
|
|
|
MPN_COPY (r->_mp_d, rp, rsize);
|
|
r->_mp_size = (e & 1) == 0 || b->_mp_size >= 0 ? rsize : -rsize;
|
|
TMP_FREE (marker);
|
|
}
|