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1 files changed, 147 insertions, 0 deletions

diff --git a/contrib/SDL-3.2.8/include/SDL3/SDL_bits.h b/contrib/SDL-3.2.8/include/SDL3/SDL_bits.h
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+++ b/contrib/SDL-3.2.8/include/SDL3/SDL_bits.h
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+/*
+  Simple DirectMedia Layer
+  Copyright (C) 1997-2025 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.
+*/
+
+/**
+ * # CategoryBits
+ *
+ * Functions for fiddling with bits and bitmasks.
+ */
+
+#ifndef SDL_bits_h_
+#define SDL_bits_h_
+
+#include <SDL3/SDL_stdinc.h>
+
+#include <SDL3/SDL_begin_code.h>
+/* Set up for C function definitions, even when using C++ */
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#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
+
+/**
+ * Get the index of the most significant (set) bit in a 32-bit number.
+ *
+ * Result is undefined when called with 0. This operation can also be stated
+ * as "count leading zeroes" and "log base 2".
+ *
+ * Note that this is a forced-inline function in a header, and not a public
+ * API function available in the SDL library (which is to say, the code is
+ * embedded in the calling program and the linker and dynamic loader will not
+ * be able to find this function inside SDL itself).
+ *
+ * \param x the 32-bit value to examine.
+ * \returns the index of the most significant bit, or -1 if the value is 0.
+ *
+ * \threadsafety It is safe to call this function from any thread.
+ *
+ * \since This function is available since SDL 3.2.0.
+ */
+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) && _MSC_VER >= 1400
+    unsigned long index;
+    if (_BitScanReverse(&index, x)) {
+        return (int)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
+}
+
+/**
+ * Determine if a unsigned 32-bit value has exactly one bit set.
+ *
+ * If there are no bits set (`x` is zero), or more than one bit set, this
+ * returns false. If any one bit is exclusively set, this returns true.
+ *
+ * Note that this is a forced-inline function in a header, and not a public
+ * API function available in the SDL library (which is to say, the code is
+ * embedded in the calling program and the linker and dynamic loader will not
+ * be able to find this function inside SDL itself).
+ *
+ * \param x the 32-bit value to examine.
+ * \returns true if exactly one bit is set in `x`, false otherwise.
+ *
+ * \threadsafety It is safe to call this function from any thread.
+ *
+ * \since This function is available since SDL 3.2.0.
+ */
+SDL_FORCE_INLINE bool SDL_HasExactlyOneBitSet32(Uint32 x)
+{
+    if (x && !(x & (x - 1))) {
+        return true;
+    }
+    return false;
+}
+
+/* Ends C function definitions when using C++ */
+#ifdef __cplusplus
+}
+#endif
+#include <SDL3/SDL_close_code.h>
+
+#endif /* SDL_bits_h_ */