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/* PCSX2 - PS2 Emulator for PCs
* Copyright (C) 2014- PCSX2 Dev Team
*
* PCSX2 is free software: you can redistribute it and/or modify it under the terms
* of the GNU Lesser General Public License as published by the Free Software Found-
* ation, either version 3 of the License, or (at your option) any later version.
*
* PCSX2 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 a copy of the GNU General Public License along with PCSX2.
* If not, see <http://www.gnu.org/licenses/>.
*/
#pragma once
// Hopefully this file will be used for cross-source math utilities.
// Currently these are strewn across the code base. Please collect them all!
#include "Pcsx2Defs.h"
// On GCC >= 4.7, this is equivalent to __builtin_clrsb(n);
inline u32 count_leading_sign_bits(s32 n)
{
// If the sign bit is 1, we invert the bits to 0 for count-leading-zero.
if (n < 0)
n = ~n;
// If BSR is used directly, it would have an undefined value for 0.
if (n == 0)
return 32;
// Perform our count leading zero.
#ifdef _MSC_VER
unsigned long ret;
_BitScanReverse(&ret, n);
return 31 - (u32)ret;
#else
return __builtin_clz(n);
#endif
}
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