aarch64: implement videodsp.prefetch

8% faster h264 decoding on Apple A7.

libavcodec/aarch64/Makefile

@@ -3,10 +3,13 @@ OBJS-$(CONFIG_H264DSP)                  += aarch64/h264dsp_init_aarch64.o
 OBJS-$(CONFIG_H264QPEL)                 += aarch64/h264qpel_init_aarch64.o
 OBJS-$(CONFIG_HPELDSP)                  += aarch64/hpeldsp_init_aarch64.o
 OBJS-$(CONFIG_NEON_CLOBBER_TEST)        += aarch64/neontest.o
+OBJS-$(CONFIG_VIDEODSP)                 += aarch64/videodsp_init.o
 
 OBJS-$(CONFIG_RV40_DECODER)             += aarch64/rv40dsp_init_aarch64.o
 OBJS-$(CONFIG_VC1_DECODER)              += aarch64/vc1dsp_init_aarch64.o
 
+ARMV8-OBJS-$(CONFIG_VIDEODSP)           += aarch64/videodsp.o
+
 NEON-OBJS-$(CONFIG_H264CHROMA)          += aarch64/h264cmc_neon.o
 NEON-OBJS-$(CONFIG_H264DSP)             += aarch64/h264dsp_neon.o              \
                                            aarch64/h264idct_neon.o

libavcodec/aarch64/videodsp.S

@@ -0,0 +1,28 @@
+/*
+ * 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 "libavutil/aarch64/asm.S"
+
+function ff_prefetch_aarch64, export=1
+        subs            w2,  w2,  #2
+        prfm            pldl1strm, [x0]
+        prfm            pldl1strm, [x0,  x1]
+        add             x0,  x0,  x1,  lsl #1
+        b.gt            X(ff_prefetch_aarch64)
+        ret
+endfunc

libavcodec/aarch64/videodsp_init.c

@@ -0,0 +1,32 @@
+/*
+ * 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 "libavutil/attributes.h"
+#include "libavutil/cpu.h"
+#include "libavutil/aarch64/cpu.h"
+#include "libavcodec/videodsp.h"
+
+void ff_prefetch_aarch64(uint8_t *mem, ptrdiff_t stride, int h);
+
+av_cold void ff_videodsp_init_aarch64(VideoDSPContext *ctx, int bpc)
+{
+    int cpu_flags = av_get_cpu_flags();
+
+    if (have_armv8(cpu_flags))
+        ctx->prefetch = ff_prefetch_aarch64;
+}

libavcodec/videodsp.c

@@ -43,6 +43,8 @@ av_cold void ff_videodsp_init(VideoDSPContext *ctx, int bpc)
         ctx->emulated_edge_mc = ff_emulated_edge_mc_16;
     }
 
+    if (ARCH_AARCH64)
+        ff_videodsp_init_aarch64(ctx, bpc);
     if (ARCH_ARM)
         ff_videodsp_init_arm(ctx, bpc);
     if (ARCH_PPC)

libavcodec/videodsp.h

@@ -68,6 +68,7 @@ typedef struct VideoDSPContext {
 void ff_videodsp_init(VideoDSPContext *ctx, int bpc);
 
 /* for internal use only (i.e. called by ff_videodsp_init() */
+void ff_videodsp_init_aarch64(VideoDSPContext *ctx, int bpc);
 void ff_videodsp_init_arm(VideoDSPContext *ctx, int bpc);
 void ff_videodsp_init_ppc(VideoDSPContext *ctx, int bpc);
 void ff_videodsp_init_x86(VideoDSPContext *ctx, int bpc);