audioflinger: Optimze ditherAndClamp with ARM NEON (7c4e8709) · Commits · e / os / android_frameworks_base

services/audioflinger/Android.mk

+4 −0

Original line number	Diff line number	Diff line
		@@ -34,4 +34,8 @@ ifeq ($(BOARD_USE_MOTO_DOCK_HACK),true)
		LOCAL_CFLAGS += -DMOTO_DOCK_HACK
		endif

		ifeq ($(ARCH_ARM_HAVE_NEON),true)
		LOCAL_CFLAGS += -D__ARM_HAVE_NEON
		endif

		include $(BUILD_SHARED_LIBRARY)

+15 −0

Original line number	Diff line number	Diff line
		@@ -32,6 +32,10 @@

		#include "AudioMixer.h"

		#if defined(__ARM_HAVE_NEON)
		#include <arm_neon.h>
		#endif

		namespace android {
		// ----------------------------------------------------------------------------

		@@ -864,7 +868,18 @@ void AudioMixer::track__16BitsMono(track_t* t, int32_t* out, size_t frameCount,

		void AudioMixer::ditherAndClamp(int32_t* out, int32_t const *sums, size_t c)
		{
		#if defined(__ARM_HAVE_NEON)
		for (size_t i=0; i<(c>>1); i++) {
		int16x4_t clamped_vec = vqshrn_n_s32(vld1q_s32(sums), 12);
		vst1_s16((int16_t*)out, clamped_vec);
		sums += 4;
		out += 2;
		}
		/* the remaining */
		for (size_t i=0; i<(c&1); i++) {
		#else
		for (size_t i=0 ; i<c ; i++) {
		#endif
		int32_t l = *sums++;
		int32_t r = *sums++;
		int32_t nl = l >> 12;