ioq3/code/SDL2/include/SDL_bits.h
Zack Middleton 02a12f2dec Update to SDL 2.24.0 and add separate macOS UB2 dylib
Update mingw and macOS SDL libraries to 2.24.0. (MSVC .lib files and
Xcode project haven't been updated.)

There is now a separate SDL dylib for macOS Universal Binary 1 and 2
because SDL 2.24.0 dropped support for macOS 10.6 (which is last to
support x86). Documentation says SDL 2.24.0 also dropped macOS 10.7
and 10.8 too. So UB2 is now 10.9 or later while 10.5 to 10.8 live in
UB1.

Compiled using osxcross with macOS 11.3 SDK. Ran "strip -x" on Windows
and macOS libraries. Ad-hoc signed dylib using PyOxidizer rcodesign to
fix digest checksums after strip.
2023-02-19 13:08:36 -05:00

126 lines
3.1 KiB
C

/*
Simple DirectMedia Layer
Copyright (C) 1997-2022 Sam Lantinga <slouken@libsdl.org>
This software is provided 'as-is', without any express or implied
warranty. In no event will the authors be held liable for any damages
arising from the use of this software.
Permission is granted to anyone to use this software for any purpose,
including commercial applications, and to alter it and redistribute it
freely, subject to the following restrictions:
1. The origin of this software must not be misrepresented; you must not
claim that you wrote the original software. If you use this software
in a product, an acknowledgment in the product documentation would be
appreciated but is not required.
2. Altered source versions must be plainly marked as such, and must not be
misrepresented as being the original software.
3. This notice may not be removed or altered from any source distribution.
*/
/**
* \file SDL_bits.h
*
* Functions for fiddling with bits and bitmasks.
*/
#ifndef SDL_bits_h_
#define SDL_bits_h_
#include "SDL_stdinc.h"
#include "begin_code.h"
/* Set up for C function definitions, even when using C++ */
#ifdef __cplusplus
extern "C" {
#endif
/**
* \file SDL_bits.h
*/
/**
* Get the index of the most significant bit. Result is undefined when called
* with 0. This operation can also be stated as "count leading zeroes" and
* "log base 2".
*
* \return the index of the most significant bit, or -1 if the value is 0.
*/
#if defined(__WATCOMC__) && defined(__386__)
extern __inline int _SDL_bsr_watcom(Uint32);
#pragma aux _SDL_bsr_watcom = \
"bsr eax, eax" \
parm [eax] nomemory \
value [eax] \
modify exact [eax] nomemory;
#endif
SDL_FORCE_INLINE int
SDL_MostSignificantBitIndex32(Uint32 x)
{
#if defined(__GNUC__) && (__GNUC__ >= 4 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 4))
/* Count Leading Zeroes builtin in GCC.
* http://gcc.gnu.org/onlinedocs/gcc-4.3.4/gcc/Other-Builtins.html
*/
if (x == 0) {
return -1;
}
return 31 - __builtin_clz(x);
#elif defined(__WATCOMC__) && defined(__386__)
if (x == 0) {
return -1;
}
return _SDL_bsr_watcom(x);
#elif defined(_MSC_VER)
unsigned long index;
if (_BitScanReverse(&index, x)) {
return index;
}
return -1;
#else
/* Based off of Bit Twiddling Hacks by Sean Eron Anderson
* <seander@cs.stanford.edu>, released in the public domain.
* http://graphics.stanford.edu/~seander/bithacks.html#IntegerLog
*/
const Uint32 b[] = {0x2, 0xC, 0xF0, 0xFF00, 0xFFFF0000};
const int S[] = {1, 2, 4, 8, 16};
int msbIndex = 0;
int i;
if (x == 0) {
return -1;
}
for (i = 4; i >= 0; i--)
{
if (x & b[i])
{
x >>= S[i];
msbIndex |= S[i];
}
}
return msbIndex;
#endif
}
SDL_FORCE_INLINE SDL_bool
SDL_HasExactlyOneBitSet32(Uint32 x)
{
if (x && !(x & (x - 1))) {
return SDL_TRUE;
}
return SDL_FALSE;
}
/* Ends C function definitions when using C++ */
#ifdef __cplusplus
}
#endif
#include "close_code.h"
#endif /* SDL_bits_h_ */
/* vi: set ts=4 sw=4 expandtab: */