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author | markm <markm@FreeBSD.org> | 1996-10-20 08:09:18 +0000 |
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committer | markm <markm@FreeBSD.org> | 1996-10-20 08:09:18 +0000 |
commit | 95051df139229f811dc922523d1891a293f026f2 (patch) | |
tree | 9585e7166d60983ae58d5a9cef796d1ba00eb841 /gnu/lib/libgmp/mpz/ui_pow_ui.c | |
parent | 8fb2c1d48a4e45c88b648528be59e08aede061de (diff) | |
download | FreeBSD-src-95051df139229f811dc922523d1891a293f026f2.zip FreeBSD-src-95051df139229f811dc922523d1891a293f026f2.tar.gz |
Import of GNU MP 2.0.2
This is a clean import with only the non-x86 bits removed. Makefiles and
other will follow.
Requested by: Andrey Chernov
Made world by: Chuck Robey
Diffstat (limited to 'gnu/lib/libgmp/mpz/ui_pow_ui.c')
-rw-r--r-- | gnu/lib/libgmp/mpz/ui_pow_ui.c | 111 |
1 files changed, 111 insertions, 0 deletions
diff --git a/gnu/lib/libgmp/mpz/ui_pow_ui.c b/gnu/lib/libgmp/mpz/ui_pow_ui.c new file mode 100644 index 0000000..19baca1 --- /dev/null +++ b/gnu/lib/libgmp/mpz/ui_pow_ui.c @@ -0,0 +1,111 @@ +/* mpz_ui_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. */ + +#include "gmp.h" +#include "gmp-impl.h" +#include "longlong.h" + +void +#if __STDC__ +mpz_ui_pow_ui (mpz_ptr r, unsigned long int b, unsigned long int e) +#else +mpz_ui_pow_ui (r, b, e) + mpz_ptr r; + unsigned long int b; + unsigned long int e; +#endif +{ + mp_ptr rp, tp, xp; + mp_size_t rsize; + int cnt, i; + mp_limb_t blimb = b; + TMP_DECL (marker); + + /* 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 (blimb == 0) + { + r->_mp_size = 0; + return; + } + + if (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 = 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); + + rp[0] = blimb; + rsize = 1; + 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) + { + mp_limb_t cy; + cy = mpn_mul_1 (tp, rp, rsize, blimb); + if (cy != 0) + { + tp[rsize] = cy; + rsize++; + } + 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 = rsize; + TMP_FREE (marker); +} |