ARM: libavresample: NEON optimised flat float to s16 conversion

Signed-off-by: Mans Rullgard <mans@mansr.com>

libavresample/arm/Makefile

+OBJS      += arm/audio_convert_init.o
+NEON-OBJS += arm/audio_convert_neon.o

libavresample/arm/audio_convert_init.c

+/*
+ * This file is part of Libav.
+ *
+ * Libav is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * Libav is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <stdint.h>
+
+#include "config.h"
+#include "libavutil/attributes.h"
+#include "libavutil/cpu.h"
+#include "libavutil/arm/cpu.h"
+#include "libavutil/samplefmt.h"
+#include "libavresample/audio_convert.h"
+
+void ff_conv_flt_to_s16_neon(int16_t *dst, const float *src, int len);
+
+av_cold void ff_audio_convert_init_arm(AudioConvert *ac)
+{
+    int cpu_flags = av_get_cpu_flags();
+
+    if (have_neon(cpu_flags)) {
+        ff_audio_convert_set_func(ac, AV_SAMPLE_FMT_S16, AV_SAMPLE_FMT_FLT,
+                                  0, 16, 8, "NEON",
+                                  ff_conv_flt_to_s16_neon);
+    }
+}

libavresample/arm/audio_convert_neon.S

+/*
+ * Copyright (c) 2008 Mans Rullgard <mans@mansr.com>
+ *
+ * This file is part of Libav.
+ *
+ * Libav is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * Libav is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "config.h"
+#include "libavutil/arm/asm.S"
+
+function ff_conv_flt_to_s16_neon, export=1
+        subs            r2,  r2,  #8
+        vld1.32         {q0},     [r1,:128]!
+        vcvt.s32.f32    q8,  q0,  #31
+        vld1.32         {q1},     [r1,:128]!
+        vcvt.s32.f32    q9,  q1,  #31
+        beq             3f
+        bics            r12, r2,  #15
+        beq             2f
+1:      subs            r12, r12, #16
+        vqrshrn.s32     d4,  q8,  #16
+        vld1.32         {q0},     [r1,:128]!
+        vcvt.s32.f32    q0,  q0,  #31
+        vqrshrn.s32     d5,  q9,  #16
+        vld1.32         {q1},     [r1,:128]!
+        vcvt.s32.f32    q1,  q1,  #31
+        vqrshrn.s32     d6,  q0,  #16
+        vst1.16         {q2},     [r0,:128]!
+        vqrshrn.s32     d7,  q1,  #16
+        vld1.32         {q8},     [r1,:128]!
+        vcvt.s32.f32    q8,  q8,  #31
+        vld1.32         {q9},     [r1,:128]!
+        vcvt.s32.f32    q9,  q9,  #31
+        vst1.16         {q3},     [r0,:128]!
+        bne             1b
+        ands            r2,  r2,  #15
+        beq             3f
+2:      vld1.32         {q0},     [r1,:128]!
+        vqrshrn.s32     d4,  q8,  #16
+        vcvt.s32.f32    q0,  q0,  #31
+        vld1.32         {q1},     [r1,:128]!
+        vqrshrn.s32     d5,  q9,  #16
+        vcvt.s32.f32    q1,  q1,  #31
+        vqrshrn.s32     d6,  q0,  #16
+        vst1.16         {q2},     [r0,:128]!
+        vqrshrn.s32     d7,  q1,  #16
+        vst1.16         {q3},     [r0,:128]!
+        bx              lr
+3:      vqrshrn.s32     d4,  q8,  #16
+        vqrshrn.s32     d5,  q9,  #16
+        vst1.16         {q2},     [r0,:128]!
+        bx              lr
+endfunc

libavresample/audio_convert.c

@@ -276,6 +276,8 @@ AudioConvert *ff_audio_convert_alloc(AVAudioResampleContext *avr,
 
     set_generic_function(ac);
 
+    if (ARCH_ARM)
+        ff_audio_convert_init_arm(ac);
     if (ARCH_X86)
         ff_audio_convert_init_x86(ac);
 

libavresample/audio_convert.h

@@ -82,6 +82,7 @@ int ff_audio_convert(AudioConvert *ac, AudioData *out, AudioData *in, int len);
 
 /* arch-specific initialization functions */
 
+void ff_audio_convert_init_arm(AudioConvert *ac);
 void ff_audio_convert_init_x86(AudioConvert *ac);
 
 #endif /* AVRESAMPLE_AUDIO_CONVERT_H */