audio: Added ARM NEON versions of audio converters.

These are _much_ faster than the scalar equivalents on the Raspberry Pi that I tested on. Often 3x to 4x as fast!
libsdl-org · May 16, 2018 · b7e88aa · b7e88aa
1 parent cb0e614
commit b7e88aa
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diff --git a/docs/README-raspberrypi.md b/docs/README-raspberrypi.md
@@ -27,6 +27,16 @@ OpenGL ES 2.x, it usually comes pre-installed, but in any case:
 
 sudo apt-get install libraspberrypi0 libraspberrypi-bin libraspberrypi-dev
 
+
+================================================================================
+ NEON
+================================================================================
+
+If your Pi has NEON support, make sure you add -mfpu=neon to your CFLAGS so
+that SDL will select some otherwise-disabled highly-optimized code. The
+original Pi units don't have NEON, the Pi2 probably does, and the Pi3
+definitely does.
+
 ================================================================================
  Cross compiling from x86 Linux
 ================================================================================

diff --git a/include/SDL_cpuinfo.h b/include/SDL_cpuinfo.h
@@ -57,6 +57,9 @@
 #undef bool
 #endif
 #endif
+#if defined(__ARM_NEON__) && !defined(SDL_DISABLE_ARM_NEON_H)
+#include <arm_neon.h>
+#endif
 #if defined(__3dNOW__) && !defined(SDL_DISABLE_MM3DNOW_H)
 #include <mm3dnow.h>
 #endif