vasilito
ff4ff35918
Red Bear OS is a full fork. All sources must be available from git clone with zero network access. Removed gitignore rules that excluded fetched source trees under recipes/*/source/, local/recipes/kde/*/source/, local/recipes/qt/*/source/, and vendor source trees. Build artifacts (target/, build/, source.tar, *.o, *.so) remain excluded. 127291 files added — kernel, relibc, base, bootloader, pkgar, all KDE/Qt frameworks, mesa, wayland, DRM drivers, and every other recipe source.
134 lines
3.9 KiB
C
134 lines
3.9 KiB
C
/* mpfr_ui_pow_ui -- compute the power between two machine integers
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Copyright 1999-2025 Free Software Foundation, Inc.
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Contributed by the Pascaline and Caramba projects, INRIA.
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This file is part of the GNU MPFR Library.
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The GNU MPFR Library is free software; you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 3 of the License, or (at your
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option) any later version.
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The GNU MPFR Library is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
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License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with the GNU MPFR Library; see the file COPYING.LESSER.
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If not, see <https://www.gnu.org/licenses/>. */
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#include "mpfr-impl.h"
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int
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mpfr_ui_pow_ui (mpfr_ptr x, unsigned long int k, unsigned long int n,
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mpfr_rnd_t rnd)
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{
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mpfr_exp_t err;
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unsigned long m;
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mpfr_t res;
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mpfr_prec_t prec;
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int size_n;
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int inexact;
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MPFR_ZIV_DECL (loop);
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MPFR_SAVE_EXPO_DECL (expo);
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MPFR_LOG_FUNC
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(("k=%lu n=%lu rnd=%d", k, n, rnd),
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("y[%Pd]=%.*Rg inexact=%d",
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mpfr_get_prec (x), mpfr_log_prec, x, inexact));
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if (MPFR_UNLIKELY (n <= 1))
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{
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if (n == 1)
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return mpfr_set_ui (x, k, rnd); /* k^1 = k */
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else
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return mpfr_set_ui (x, 1, rnd); /* k^0 = 1 for any k */
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}
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else if (MPFR_UNLIKELY (k <= 1))
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{
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if (k == 1)
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return mpfr_set_ui (x, 1, rnd); /* 1^n = 1 for any n > 0 */
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else
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return mpfr_set_ui (x, 0, rnd); /* 0^n = 0 for any n > 0 */
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}
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for (size_n = 0, m = n; m != 0; size_n++, m >>= 1)
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;
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MPFR_SAVE_EXPO_MARK (expo);
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prec = MPFR_PREC (x) + 3 + size_n;
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mpfr_init2 (res, prec);
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MPFR_ZIV_INIT (loop, prec);
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for (;;)
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{
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int i = size_n;
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unsigned int inex_res;
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inex_res = mpfr_set_ui (res, k, MPFR_RNDU);
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err = 1;
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/* now 2^(i-1) <= n < 2^i: i=1+floor(log2(n)) */
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for (i -= 2; i >= 0; i--)
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{
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inex_res |= mpfr_sqr (res, res, MPFR_RNDU);
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err++;
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if (n & (1UL << i))
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inex_res |= mpfr_mul_ui (res, res, k, MPFR_RNDU);
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}
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if (MPFR_UNLIKELY (MPFR_IS_INF (res)))
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{
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mpfr_t kf;
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mpz_t z;
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int size_k;
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MPFR_BLOCK_DECL (flags);
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/* Let's handle the overflow by calling mpfr_pow_z.
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Alternatively, we could call mpfr_pow_ui; this would
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need a bit shorter code below, but mpfr_pow_ui handles
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the overflow by calling mpfr_pow_z, so that calling
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mpfr_pow_z directly should be a bit more efficient. */
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MPFR_ZIV_FREE (loop);
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mpfr_clear (res);
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for (size_k = 0, m = k; m != 0; size_k++, m >>= 1)
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;
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mpfr_init2 (kf, size_k);
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inexact = mpfr_set_ui (kf, k, MPFR_RNDN);
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MPFR_ASSERTD (inexact == 0);
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mpz_init (z);
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mpz_set_ui (z, n);
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MPFR_BLOCK (flags, inexact = mpfr_pow_z (x, kf, z, rnd););
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mpz_clear (z);
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mpfr_clear (kf);
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MPFR_SAVE_EXPO_UPDATE_FLAGS (expo, flags);
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goto end;
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}
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/* since the loop is executed floor(log2(n)) times,
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we have err = 1+floor(log2(n)).
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Since prec >= MPFR_PREC(x) + 4 + floor(log2(n)), prec > err */
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err = prec - err;
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MPFR_LOG_VAR (res);
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if (MPFR_LIKELY (!inex_res
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|| MPFR_CAN_ROUND (res, err, MPFR_PREC (x), rnd)))
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break;
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/* Actualisation of the precision */
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MPFR_ZIV_NEXT (loop, prec);
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mpfr_set_prec (res, prec);
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}
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MPFR_ZIV_FREE (loop);
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inexact = mpfr_set (x, res, rnd);
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mpfr_clear (res);
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end:
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MPFR_SAVE_EXPO_FREE (expo);
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return mpfr_check_range (x, inexact, rnd);
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}
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