NEON float to fixed point vectorized conversion

modules/audio_filter/converter/Modules.am

 SOURCES_converter_fixed = fixed.c
 SOURCES_converter_float = float.c
+SOURCES_converter_neon = neon.c
 SOURCES_a52tospdif = a52tospdif.c
 SOURCES_a52tofloat32 = a52tofloat32.c
 SOURCES_dtstospdif = dtstospdif.c
@@ -9,3 +10,6 @@ SOURCES_mpgatofixed32 = mpgatofixed32.c
 libvlc_LTLIBRARIES += \
 	libconverter_fixed_plugin.la \
 	$(NULL)
+if HAVE_NEON
+libvlc_LTLIBRARIES += libconverter_neon_plugin.la
+endif

modules/audio_filter/converter/neon.c

+/*****************************************************************************
+ * arm_neon.c: NEON assembly optimized audio conversions
+ *****************************************************************************
+ * Copyright (C) 2009 Rémi Denis-Courmont
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
+ *****************************************************************************/
+
+#ifdef HAVE_CONFIG_H
+# include "config.h"
+#endif
+
+#include <vlc_common.h>
+#include <vlc_plugin.h>
+#include <vlc_aout.h>
+
+static int Open (vlc_object_t *);
+
+vlc_module_begin ()
+    set_description (N_("ARM NEON audio format conversions") )
+    add_submodule ()
+        set_capability ("audio filter", 20)
+        set_callbacks (Open, NULL)
+vlc_module_end ()
+
+static void Do_F32_S32 (aout_instance_t *, aout_filter_t *,
+                        aout_buffer_t *, aout_buffer_t *);
+
+static int Open (vlc_object_t *obj)
+{
+    aout_filter_t *filter = (aout_filter_t *)obj;
+
+    if (!(vlc_CPU () & CPU_CAPABILITY_NEON))
+        return VLC_EGENERIC;
+    if (!AOUT_FMTS_SIMILAR (&filter->input, &filter->output))
+        return VLC_EGENERIC;
+
+    if (filter->input.i_format == VLC_CODEC_FL32)
+    {
+        if (filter->output.i_format == VLC_CODEC_FI32)
+            filter->pf_do_work = Do_F32_S32;
+        else
+            return VLC_EGENERIC;
+    }
+    else
+        return VLC_EGENERIC;
+
+    filter->b_in_place = true;
+    return 0;
+}
+
+/**
+ * Half-precision floating point to signed fixed point conversion.
+ */
+static void Do_F32_S32 (aout_instance_t *aout, aout_filter_t *filter,
+                        aout_buffer_t *inbuf, aout_buffer_t *outbuf)
+{
+    unsigned nb_samples = inbuf->i_nb_samples
+                     * aout_FormatNbChannels (&filter->input);
+    const float *inp = (float *)inbuf->p_buffer;
+    const float *endp = inp + nb_samples;
+    int32_t *outp = (int32_t *)outbuf->p_buffer;
+
+    if (nb_samples & 1)
+        *(outp++) = *(inp++) * FIXED32_ONE;
+
+    if (nb_samples & 2)
+        asm volatile (
+            "vld1.f32 {d0}, [%[inp]]!\n"
+            "vcvt.s32.f32 d1, d0, #28\n"
+            "vst1.s32 {d1}, [%[outp]]!\n"
+            : [outp] "+r" (outp), [inp] "+r" (inp)
+            :
+            : "q0", "memory");
+
+    if (nb_samples & 4)
+        asm volatile (
+            "vld2.f32 {q0}, [%[inp]]!\n"
+            "vcvt.s32.f32 q1, q0, #28\n"
+            "vst2.s32 {q1}, [%[outp]]!\n"
+            : [outp] "+r" (outp), [inp] "+r" (inp)
+            :
+            : "q0", "q1", "memory");
+
+    while (inp != endp)
+        asm volatile (
+            "vld4.f32 {q0-q1}, [%[inp]]!\n"
+            "vcvt.s32.f32 q2, q0, #28\n"
+            "vcvt.s32.f32 q3, q1, #28\n"
+            "vst4.s32 {q2-q3}, [%[outp]]!\n"
+            : [outp] "+r" (outp), [inp] "+r" (inp)
+            :
+            : "q0", "q1", "q2", "q3", "memory");
+
+    outbuf->i_nb_samples = inbuf->i_nb_samples;
+    outbuf->i_nb_bytes = inbuf->i_nb_bytes;
+    (void) aout;
+}