Coverage Report

Created: 2024-11-21 07:03

/src/libgmp/mpn/scan0.c
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/* mpn_scan0 -- Scan from a given bit position for the next clear bit.
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Copyright 1994, 1996, 2001, 2002, 2004 Free Software Foundation, Inc.
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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
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it under the terms of either:
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  * the GNU Lesser General Public License as published by the Free
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    Software Foundation; either version 3 of the License, or (at your
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    option) any later version.
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or
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  * the GNU General Public License as published by the Free Software
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    Foundation; either version 2 of the License, or (at your option) any
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    later version.
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or both in parallel, as here.
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The GNU MP 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 General Public License
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for more details.
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You should have received copies of the GNU General Public License and the
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GNU Lesser General Public License along with the GNU MP Library.  If not,
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see https://www.gnu.org/licenses/.  */
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#include "gmp-impl.h"
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#include "longlong.h"
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/* Argument constraints:
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   1. U must sooner or later have a limb with a clear bit.
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 */
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mp_bitcnt_t
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mpn_scan0 (mp_srcptr up, mp_bitcnt_t starting_bit)
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{
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  mp_size_t starting_word;
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  mp_limb_t alimb;
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  int cnt;
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  mp_srcptr p;
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  /* Start at the word implied by STARTING_BIT.  */
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  starting_word = starting_bit / GMP_NUMB_BITS;
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  p = up + starting_word;
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  alimb = *p++ ^ GMP_NUMB_MASK;
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  /* Mask off any bits before STARTING_BIT in the first limb.  */
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  alimb &= - (mp_limb_t) 1 << (starting_bit % GMP_NUMB_BITS);
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  while (alimb == 0)
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    alimb = *p++ ^ GMP_NUMB_MASK;
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  count_trailing_zeros (cnt, alimb);
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  return (p - up - 1) * GMP_NUMB_BITS + cnt;
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}