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/*
* University of Illinois/NCSA Open Source License
*
* Copyright (c) 2003-2012 University of Illinois at Urbana-Champaign.
* All rights reserved.
*
* Developed by:
*
* LLVM Team
*
* University of Illinois at Urbana-Champaign
*
* http://llvm.org
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* with the Software without restriction, including without limitation the
* rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
* sell copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* * Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimers.
*
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimers in the
* documentation and/or other materials provided with the distribution.
*
* * Neither the names of the LLVM Team, University of Illinois at
* Urbana-Champaign, nor the names of its contributors may be used to
* endorse or promote products derived from this Software without specific
* prior written permission.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* CONTRIBUTORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS WITH
* THE SOFTWARE.
*/
/*
* C compiler runtime logic for popcount() related builtins taken from LLVM. See
* also the Hacker's Delight 2nd Edition.
*/
int
__popcountdi2(unsigned long long val)
{
unsigned long long x2 = (unsigned long long)val;
x2 = x2 - ((x2 >> 1) & 0x5555555555555555uLL);
/* Every 2 bits holds the sum of every pair of bits (32) */
x2 = ((x2 >> 2) & 0x3333333333333333uLL) + (x2 & 0x3333333333333333uLL);
/*
* Every 4 bits holds the sum of every 4-set of bits (3 significant
* bits) (16)
*/
x2 = (x2 + (x2 >> 4)) & 0x0F0F0F0F0F0F0F0FuLL;
/*
* Every 8 bits holds the sum of every 8-set of bits (4 significant
* bits) (8).
*/
unsigned x = (unsigned)(x2 + (x2 >> 32));
/*
* The lower 32 bits hold four 16 bit sums (5 significant bits). The
* upper 32 bits are garbage.
*/
x = x + (x >> 16);
/*
* The lower 16 bits hold two 32 bit sums (6 significant bits). The
* upper 16 bits are garbage. Extract the 7 significant bits.
*/
return ((x + (x >> 8)) & 0x0000007F);
}
int
__popcountsi2(unsigned val)
{
unsigned x = (unsigned)val;
x = x - ((x >> 1) & 0x55555555);
/* Every 2 bits holds the sum of every pair of bits */
x = ((x >> 2) & 0x33333333) + (x & 0x33333333);
/*
* Every 4 bits holds the sum of every 4-set of bits (3 significant
* bits).
*/
x = (x + (x >> 4)) & 0x0F0F0F0F;
/*
* Every 8 bits holds the sum of every 8-set of bits (4 significant
* bits).
*/
x = (x + (x >> 16));
/*
* The lower 16 bits hold two 8 bit sums (5 significant bits). The
* upper 16 bits are garbage. Extract the 6 significant bits.
*/
return ((x + (x >> 8)) & 0x0000003F); /* (6 significant bits) */
}
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