avcodec/ac3: Implement float_to_fixed24 for aarch64 NEON

Signed-off-by: Geoff Hill <geoff@geoffhill.org>
Signed-off-by: Martin Storsjö <martin@martin.st>

libavcodec/aarch64/Makefile

@@ -1,4 +1,5 @@
 # subsystems
+OBJS-$(CONFIG_AC3DSP)                   += aarch64/ac3dsp_init_aarch64.o
 OBJS-$(CONFIG_FMTCONVERT)               += aarch64/fmtconvert_init.o
 OBJS-$(CONFIG_H264CHROMA)               += aarch64/h264chroma_init_aarch64.o
 OBJS-$(CONFIG_H264DSP)                  += aarch64/h264dsp_init_aarch64.o
@@ -35,6 +36,7 @@ ARMV8-OBJS-$(CONFIG_VIDEODSP)           += aarch64/videodsp.o
 
 # subsystems
 NEON-OBJS-$(CONFIG_AAC_DECODER)         += aarch64/sbrdsp_neon.o
+NEON-OBJS-$(CONFIG_AC3DSP)              += aarch64/ac3dsp_neon.o
 NEON-OBJS-$(CONFIG_FMTCONVERT)          += aarch64/fmtconvert_neon.o
 NEON-OBJS-$(CONFIG_H264CHROMA)          += aarch64/h264cmc_neon.o
 NEON-OBJS-$(CONFIG_H264DSP)             += aarch64/h264dsp_neon.o              \

libavcodec/aarch64/ac3dsp_init_aarch64.c

@@ -0,0 +1,36 @@
+/*
+ * Copyright (c) 2024 Geoff Hill <geoff@geoffhill.org>
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg 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.
+ *
+ * FFmpeg 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 FFmpeg; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include <stdint.h>
+
+#include "libavutil/arm/cpu.h"
+#include "libavutil/attributes.h"
+#include "libavcodec/ac3dsp.h"
+#include "config.h"
+
+void ff_float_to_fixed24_neon(int32_t *dst, const float *src, size_t len);
+
+av_cold void ff_ac3dsp_init_aarch64(AC3DSPContext *c)
+{
+    int cpu_flags = av_get_cpu_flags();
+    if (!have_neon(cpu_flags)) return;
+
+    c->float_to_fixed24 = ff_float_to_fixed24_neon;
+}

libavcodec/aarch64/ac3dsp_neon.S

@@ -0,0 +1,36 @@
+/*
+ * Copyright (c) 2011 Mans Rullgard <mans@mansr.com>
+ * Copyright (c) 2024 Geoff Hill <geoff@geoffhill.org>
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg 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.
+ *
+ * FFmpeg 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 FFmpeg; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "libavutil/aarch64/asm.S"
+
+function ff_float_to_fixed24_neon, export=1
+1:      ld1             {v0.4s, v1.4s}, [x1], #32
+        fcvtzs          v0.4s, v0.4s, #24
+        ld1             {v2.4s, v3.4s}, [x1], #32
+        fcvtzs          v1.4s, v1.4s, #24
+        fcvtzs          v2.4s, v2.4s, #24
+        st1             {v0.4s, v1.4s}, [x0], #32
+        fcvtzs          v3.4s, v3.4s, #24
+        st1             {v2.4s, v3.4s}, [x0], #32
+        subs            w2, w2, #16
+        b.ne            1b
+        ret
+endfunc

libavcodec/ac3dsp.c

@@ -389,7 +389,9 @@ av_cold void ff_ac3dsp_init(AC3DSPContext *c)
     c->downmix               = NULL;
     c->downmix_fixed         = NULL;
 
-#if ARCH_ARM
+#if ARCH_AARCH64
+    ff_ac3dsp_init_aarch64(c);
+#elif ARCH_ARM
     ff_ac3dsp_init_arm(c);
 #elif ARCH_X86
     ff_ac3dsp_init_x86(c);

libavcodec/ac3dsp.h

@@ -106,7 +106,8 @@ typedef struct AC3DSPContext {
     void (*downmix_fixed)(int32_t **samples, int16_t **matrix, int len);
 } AC3DSPContext;
 
-void ff_ac3dsp_init    (AC3DSPContext *c);
+void ff_ac3dsp_init(AC3DSPContext *c);
+void ff_ac3dsp_init_aarch64(AC3DSPContext *c);
 void ff_ac3dsp_init_arm(AC3DSPContext *c);
 void ff_ac3dsp_init_x86(AC3DSPContext *c);
 void ff_ac3dsp_init_mips(AC3DSPContext *c);