SDL_atomic.h in gosu-1.4.5

- old
+ new
@@ -235,9 +235,29 @@
 #define SDL_MemoryBarrierRelease()  SDL_CompilerBarrier()
 #define SDL_MemoryBarrierAcquire()  SDL_CompilerBarrier()
 #endif
 #endif
 
+/* "REP NOP" is PAUSE, coded for tools that don't know it by that name. */
+#if (defined(__GNUC__) || defined(__clang__)) && (defined(__i386__) || defined(__x86_64__))
+    #define SDL_CPUPauseInstruction() __asm__ __volatile__("pause\n")  /* Some assemblers can't do REP NOP, so go with PAUSE. */
+#elif (defined(__arm__) && __ARM_ARCH >= 7) || defined(__aarch64__)
+    #define SDL_CPUPauseInstruction() __asm__ __volatile__("yield" ::: "memory")
+#elif (defined(__powerpc__) || defined(__powerpc64__))
+    #define SDL_CPUPauseInstruction() __asm__ __volatile__("or 27,27,27");
+#elif defined(_MSC_VER) && (defined(_M_IX86) || defined(_M_X64))
+    #define SDL_CPUPauseInstruction() _mm_pause()  /* this is actually "rep nop" and not a SIMD instruction. No inline asm in MSVC x86-64! */
+#elif defined(_MSC_VER) && (defined(_M_ARM) || defined(_M_ARM64))
+    #define SDL_CPUPauseInstruction() __yield()
+#elif defined(__WATCOMC__) && defined(__386__)
+    /* watcom assembler rejects PAUSE if CPU < i686, and it refuses REP NOP as an invalid combination. Hardcode the bytes.  */
+    extern __inline void SDL_CPUPauseInstruction(void);
+    #pragma aux SDL_CPUPauseInstruction = "db 0f3h,90h"
+#else
+    #define SDL_CPUPauseInstruction()
+#endif
+
+
 /**
  * \brief A type representing an atomic integer value.  It is a struct
  *        so people don't accidentally use numeric operations on it.
  */
 typedef struct { int value; } SDL_atomic_t;