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.
104 lines
3.1 KiB
C
104 lines
3.1 KiB
C
/* mpz_combit -- complement a specified bit.
|
|
|
|
Copyright 2002, 2003, 2012, 2015 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_combit (mpz_ptr d, mp_bitcnt_t bit_index)
|
|
{
|
|
mp_size_t dsize = SIZ(d);
|
|
mp_ptr dp = PTR(d);
|
|
|
|
mp_size_t limb_index = bit_index / GMP_NUMB_BITS;
|
|
mp_limb_t bit = (CNST_LIMB (1) << (bit_index % GMP_NUMB_BITS));
|
|
|
|
/* Check for the most common case: Positive input, no realloc or
|
|
normalization needed. */
|
|
if (limb_index + 1 < dsize)
|
|
dp[limb_index] ^= bit;
|
|
|
|
/* Check for the hairy case. d < 0, and we have all zero bits to the
|
|
right of the bit to toggle. */
|
|
else if (limb_index < -dsize
|
|
&& (limb_index == 0 || mpn_zero_p (dp, limb_index))
|
|
&& (dp[limb_index] & (bit - 1)) == 0)
|
|
{
|
|
ASSERT (dsize < 0);
|
|
dsize = -dsize;
|
|
|
|
if (dp[limb_index] & bit)
|
|
{
|
|
/* We toggle the least significant one bit. Corresponds to
|
|
an add, with potential carry propagation, on the absolute
|
|
value. */
|
|
dp = MPZ_REALLOC (d, 1 + dsize);
|
|
dp[dsize] = 0;
|
|
MPN_INCR_U (dp + limb_index, 1 + dsize - limb_index, bit);
|
|
SIZ(d) = - dsize - dp[dsize];
|
|
}
|
|
else
|
|
{
|
|
/* We toggle a zero bit, subtract from the absolute value. */
|
|
MPN_DECR_U (dp + limb_index, dsize - limb_index, bit);
|
|
/* The absolute value shrinked by at most one bit. */
|
|
dsize -= dp[dsize - 1] == 0;
|
|
ASSERT (dsize > 0 && dp[dsize - 1] != 0);
|
|
SIZ (d) = -dsize;
|
|
}
|
|
}
|
|
else
|
|
{
|
|
/* Simple case: Toggle the bit in the absolute value. */
|
|
dsize = ABS(dsize);
|
|
if (limb_index < dsize)
|
|
{
|
|
mp_limb_t dlimb;
|
|
dlimb = dp[limb_index] ^ bit;
|
|
dp[limb_index] = dlimb;
|
|
|
|
/* Can happen only when limb_index = dsize - 1. Avoid SIZ(d)
|
|
bookkeeping in the common case. */
|
|
if (UNLIKELY ((dlimb == 0) + limb_index == dsize)) /* dsize == limb_index + 1 */
|
|
{
|
|
/* high limb became zero, must normalize */
|
|
MPN_NORMALIZE (dp, limb_index);
|
|
SIZ (d) = SIZ (d) >= 0 ? limb_index : -limb_index;
|
|
}
|
|
}
|
|
else
|
|
{
|
|
dp = MPZ_REALLOC (d, limb_index + 1);
|
|
MPN_ZERO(dp + dsize, limb_index - dsize);
|
|
dp[limb_index++] = bit;
|
|
SIZ(d) = SIZ(d) >= 0 ? limb_index : -limb_index;
|
|
}
|
|
}
|
|
}
|