version 1.1, 2000/01/10 15:35:27 |
version 1.1.1.3, 2003/08/25 16:06:33 |
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/* mpz_pow_ui(res, base, exp) -- Set RES to BASE**EXP. |
/* mpz_pow_ui -- mpz raised to ulong. |
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Copyright (C) 1991, 1993, 1994, 1996 Free Software Foundation, Inc. |
Copyright 2001 Free Software Foundation, Inc. |
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This file is part of the GNU MP Library. |
This file is part of the GNU MP Library. |
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The GNU MP Library is free software; you can redistribute it and/or modify |
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 |
it under the terms of the GNU Lesser General Public License as published by |
the Free Software Foundation; either version 2 of the License, or (at your |
the Free Software Foundation; either version 2.1 of the License, or (at your |
option) any later version. |
option) any later version. |
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The GNU MP Library is distributed in the hope that it will be useful, but |
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 |
WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY |
or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public |
or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public |
License for more details. |
License for more details. |
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You should have received a copy of the GNU Library General Public License |
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 |
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, |
the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, |
MA 02111-1307, USA. */ |
MA 02111-1307, USA. */ |
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#ifdef BERKELEY_MP |
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#include "mp.h" |
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#endif |
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#include "gmp.h" |
#include "gmp.h" |
#include "gmp-impl.h" |
#include "gmp-impl.h" |
#include "longlong.h" |
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#ifndef BERKELEY_MP |
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void |
void |
#if __STDC__ |
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mpz_pow_ui (mpz_ptr r, mpz_srcptr b, unsigned long int e) |
mpz_pow_ui (mpz_ptr r, mpz_srcptr b, unsigned long int e) |
#else |
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mpz_pow_ui (r, b, e) |
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mpz_ptr r; |
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mpz_srcptr b; |
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unsigned long int e; |
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#endif |
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#else /* BERKELEY_MP */ |
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void |
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#if __STDC__ |
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rpow (const MINT *b, signed short int e, MINT *r) |
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#else |
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rpow (b, e, r) |
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const MINT *b; |
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signed short int e; |
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MINT *r; |
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#endif |
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#endif /* BERKELEY_MP */ |
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{ |
{ |
mp_ptr rp, bp, tp, xp; |
mpz_n_pow_ui (r, PTR(b), (mp_size_t) SIZ(b), e); |
mp_size_t rsize, bsize; |
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int cnt, i; |
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mp_limb_t blimb; |
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TMP_DECL (marker); |
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bsize = ABS (b->_mp_size); |
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/* Single out cases that give result == 0 or 1. These tests are here |
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to simplify the general code below, not to optimize. */ |
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if (e == 0) |
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{ |
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r->_mp_d[0] = 1; |
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r->_mp_size = 1; |
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return; |
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} |
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if (bsize == 0 |
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#ifdef BERKELEY_MP |
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|| e < 0 |
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#endif |
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) |
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{ |
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r->_mp_size = 0; |
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return; |
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} |
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bp = b->_mp_d; |
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blimb = bp[bsize - 1]; |
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if (bsize == 1 && blimb < 0x100) |
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{ |
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/* Estimate space requirements accurately. Using the code from the |
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`else' path would over-estimate space requirements wildly. */ |
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float lb = __mp_bases[blimb].chars_per_bit_exactly; |
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rsize = 2 + ((mp_size_t) (e / lb) / BITS_PER_MP_LIMB); |
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} |
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else |
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{ |
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/* Over-estimate space requirements somewhat. */ |
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count_leading_zeros (cnt, blimb); |
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rsize = bsize * e - cnt * e / BITS_PER_MP_LIMB + 1; |
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} |
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TMP_MARK (marker); |
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/* The two areas are used to alternatingly hold the input and recieve the |
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product for mpn_mul. (This scheme is used to fulfill the requirements |
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of mpn_mul; that the product space may not be the same as any of the |
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input operands.) */ |
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rp = (mp_ptr) TMP_ALLOC (rsize * BYTES_PER_MP_LIMB); |
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tp = (mp_ptr) TMP_ALLOC (rsize * BYTES_PER_MP_LIMB); |
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MPN_COPY (rp, bp, bsize); |
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rsize = bsize; |
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count_leading_zeros (cnt, e); |
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for (i = BITS_PER_MP_LIMB - cnt - 2; i >= 0; i--) |
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{ |
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mpn_mul_n (tp, rp, rp, rsize); |
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rsize = 2 * rsize; |
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rsize -= tp[rsize - 1] == 0; |
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xp = tp; tp = rp; rp = xp; |
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if ((e & ((mp_limb_t) 1 << i)) != 0) |
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{ |
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rsize = rsize + bsize - (mpn_mul (tp, rp, rsize, bp, bsize) == 0); |
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xp = tp; tp = rp; rp = xp; |
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} |
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} |
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/* Now then we know the exact space requirements, reallocate if |
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necessary. */ |
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if (r->_mp_alloc < rsize) |
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_mpz_realloc (r, rsize); |
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MPN_COPY (r->_mp_d, rp, rsize); |
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r->_mp_size = (e & 1) == 0 || b->_mp_size >= 0 ? rsize : -rsize; |
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TMP_FREE (marker); |
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} |
} |