Files
RedBear-OS/recipes/libs/libgmp/source/mpz/setbit.c
T
vasilito ff4ff35918 feat: track all source trees in git — full fork offline-first model
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.
2026-05-14 10:55:53 +01:00

105 lines
2.7 KiB
C

/* mpz_setbit -- set a specified bit.
Copyright 1991, 1993-1995, 1997, 1999, 2001, 2002, 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 "gmp-impl.h"
void
mpz_setbit (mpz_ptr d, mp_bitcnt_t bit_idx)
{
mp_size_t dsize = SIZ (d);
mp_ptr dp = PTR (d);
mp_size_t limb_idx;
mp_limb_t mask;
limb_idx = bit_idx / GMP_NUMB_BITS;
mask = CNST_LIMB(1) << (bit_idx % GMP_NUMB_BITS);
if (dsize >= 0)
{
if (limb_idx < dsize)
{
dp[limb_idx] |= mask;
}
else
{
/* Ugh. The bit should be set outside of the end of the
number. We have to increase the size of the number. */
dp = MPZ_REALLOC (d, limb_idx + 1);
SIZ (d) = limb_idx + 1;
MPN_ZERO (dp + dsize, limb_idx - dsize);
dp[limb_idx] = mask;
}
}
else
{
/* Simulate two's complement arithmetic, i.e. simulate
1. Set OP = ~(OP - 1) [with infinitely many leading ones].
2. Set the bit.
3. Set OP = ~OP + 1. */
dsize = -dsize;
if (limb_idx < dsize)
{
mp_size_t zero_bound;
/* No index upper bound on this loop, we're sure there's a non-zero limb
sooner or later. */
zero_bound = 0;
while (dp[zero_bound] == 0)
zero_bound++;
if (limb_idx > zero_bound)
{
mp_limb_t dlimb;
dlimb = dp[limb_idx] & ~mask;
dp[limb_idx] = dlimb;
if (UNLIKELY ((dlimb == 0) + limb_idx == dsize)) /* dsize == limb_idx + 1 */
{
/* high limb became zero, must normalize */
MPN_NORMALIZE (dp, limb_idx);
SIZ (d) = -limb_idx;
}
}
else if (limb_idx == zero_bound)
{
dp[limb_idx] = ((dp[limb_idx] - 1) & ~mask) + 1;
ASSERT (dp[limb_idx] != 0);
}
else
{
MPN_DECR_U (dp + limb_idx, dsize - limb_idx, mask);
dsize -= dp[dsize - 1] == 0;
SIZ (d) = -dsize;
}
}
}
}