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Diffstat (limited to 'Build/source/libs/gmp/gmp-6.0.0/mpz/lucnum2_ui.c')
-rw-r--r-- | Build/source/libs/gmp/gmp-6.0.0/mpz/lucnum2_ui.c | 90 |
1 files changed, 90 insertions, 0 deletions
diff --git a/Build/source/libs/gmp/gmp-6.0.0/mpz/lucnum2_ui.c b/Build/source/libs/gmp/gmp-6.0.0/mpz/lucnum2_ui.c new file mode 100644 index 00000000000..f8e4fb356f0 --- /dev/null +++ b/Build/source/libs/gmp/gmp-6.0.0/mpz/lucnum2_ui.c @@ -0,0 +1,90 @@ +/* mpz_lucnum2_ui -- calculate Lucas numbers. + +Copyright 2001, 2003, 2005, 2012 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 either: + + * the GNU Lesser General Public License as published by the Free + Software Foundation; either version 3 of the License, or (at your + option) any later version. + +or + + * the GNU General Public License as published by the Free Software + Foundation; either version 2 of the License, or (at your option) any + later version. + +or both in parallel, as here. + +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 General Public License +for more details. + +You should have received copies of the GNU General Public License and the +GNU Lesser General Public License along with the GNU MP Library. If not, +see https://www.gnu.org/licenses/. */ + +#include <stdio.h> +#include "gmp.h" +#include "gmp-impl.h" + + +void +mpz_lucnum2_ui (mpz_ptr ln, mpz_ptr lnsub1, unsigned long n) +{ + mp_ptr lp, l1p, f1p; + mp_size_t size; + mp_limb_t c; + TMP_DECL; + + ASSERT (ln != lnsub1); + + /* handle small n quickly, and hide the special case for L[-1]=-1 */ + if (n <= FIB_TABLE_LUCNUM_LIMIT) + { + mp_limb_t f = FIB_TABLE (n); + mp_limb_t f1 = FIB_TABLE ((int) n - 1); + + /* L[n] = F[n] + 2F[n-1] */ + PTR(ln)[0] = f + 2*f1; + SIZ(ln) = 1; + + /* L[n-1] = 2F[n] - F[n-1], but allow for L[-1]=-1 */ + PTR(lnsub1)[0] = (n == 0 ? 1 : 2*f - f1); + SIZ(lnsub1) = (n == 0 ? -1 : 1); + + return; + } + + TMP_MARK; + size = MPN_FIB2_SIZE (n); + f1p = TMP_ALLOC_LIMBS (size); + + lp = MPZ_REALLOC (ln, size+1); + l1p = MPZ_REALLOC (lnsub1, size+1); + + size = mpn_fib2_ui (l1p, f1p, n); + + /* L[n] = F[n] + 2F[n-1] */ +#if HAVE_NATIVE_mpn_addlsh1_n + c = mpn_addlsh1_n (lp, l1p, f1p, size); +#else + c = mpn_lshift (lp, f1p, size, 1); + c += mpn_add_n (lp, lp, l1p, size); +#endif + lp[size] = c; + SIZ(ln) = size + (c != 0); + + /* L[n-1] = 2F[n] - F[n-1] */ + c = mpn_lshift (l1p, l1p, size, 1); + c -= mpn_sub_n (l1p, l1p, f1p, size); + ASSERT ((mp_limb_signed_t) c >= 0); + l1p[size] = c; + SIZ(lnsub1) = size + (c != 0); + + TMP_FREE; +} |