/*
Simple DirectMedia Layer
- Copyright (C) 1997-2014 Sam Lantinga <slouken@libsdl.org>
+ Copyright (C) 1997-2019 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
* Functions for fiddling with bits and bitmasks.
*/
-#ifndef _SDL_bits_h
-#define _SDL_bits_h
+#ifndef SDL_bits_h_
+#define SDL_bits_h_
#include "SDL_stdinc.h"
*
* \return Index of the most significant bit, or -1 if the value is 0.
*/
+#if defined(__WATCOMC__) && defined(__386__)
+extern _inline int _SDL_clz_watcom (Uint32);
+#pragma aux _SDL_clz_watcom = \
+ "bsr eax, eax" \
+ "xor eax, 31" \
+ parm [eax] nomemory \
+ value [eax] \
+ modify exact [eax] nomemory;
+#endif
+
SDL_FORCE_INLINE int
SDL_MostSignificantBitIndex32(Uint32 x)
{
-#if defined(__GNUC__) && __GNUC__ >= 4
+#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
*/
return -1;
}
return 31 - __builtin_clz(x);
+#elif defined(__WATCOMC__) && defined(__386__)
+ if (x == 0) {
+ return -1;
+ }
+ return 31 - _SDL_clz_watcom(x);
#else
/* Based off of Bit Twiddling Hacks by Sean Eron Anderson
* <seander@cs.stanford.edu>, released in the public domain.
#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 */
+#endif /* SDL_bits_h_ */
/* vi: set ts=4 sw=4 expandtab: */