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-rw-r--r--contrib/libgmp/mpz/pow_ui.c129
1 files changed, 129 insertions, 0 deletions
diff --git a/contrib/libgmp/mpz/pow_ui.c b/contrib/libgmp/mpz/pow_ui.c
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+++ b/contrib/libgmp/mpz/pow_ui.c
@@ -0,0 +1,129 @@
+/* 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);
+}
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