arm64: int32_to_float_fmul neon asm

3% faster dts decoding on a cortex-a57.

                                 cortex-a57   cortex-a53
int32_to_float_fmul_array8_c:    1270.9       4475.6
int32_to_float_fmul_array8_neon:  328.6        569.2
int32_to_float_fmul_scalar_c:     928.5       4119.6
int32_to_float_fmul_scalar_neon:  309.1        524.1

1 files changed, 76 insertions, 0 deletions

diff --git a/libavcodec/aarch64/fmtconvert_neon.S b/libavcodec/aarch64/fmtconvert_neon.S
new file mode 100644
index 0000000000..3b33c87ade
--- /dev/null
+++ b/libavcodec/aarch64/fmtconvert_neon.S
@@ -0,0 +1,76 @@
+/*
+ * ARM NEON optimised Format Conversion Utils
+ * Copyright (c) 2008 Mans Rullgard <mans@mansr.com>
+ * Copyright (c) 2015 Janne Grunau  <janne-libav@jannau.net>
+ *
+ * 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/aarch64/asm.S"
+
+function ff_int32_to_float_fmul_scalar_neon, export=1
+        ld1             {v1.4s,v2.4s}, [x1], #32
+        scvtf           v1.4s,  v1.4s
+        scvtf           v2.4s,  v2.4s
+1:
+        subs            w2,  w2,  #8
+        fmul            v3.4s,  v1.4s,  v0.s[0]
+        fmul            v4.4s,  v2.4s,  v0.s[0]
+        b.le            2f
+        ld1             {v1.4s,v2.4s}, [x1], #32
+        st1             {v3.4s,v4.4s}, [x0], #32
+        scvtf           v1.4s,  v1.4s
+        scvtf           v2.4s,  v2.4s
+        b               1b
+2:
+        st1             {v3.4s,v4.4s}, [x0]
+        ret
+endfunc
+
+function ff_int32_to_float_fmul_array8_neon, export=1
+        lsr             w4,  w4,  #3
+        subs            w5,  w4,  #1
+        b.eq            1f
+2:
+        ld1             {v0.4s,v1.4s}, [x2], #32
+        ld1             {v2.4s,v3.4s}, [x2], #32
+        scvtf           v0.4s,  v0.4s
+        scvtf           v1.4s,  v1.4s
+        ld1             {v16.2s},  [x3], #8
+        scvtf           v2.4s,  v2.4s
+        scvtf           v3.4s,  v3.4s
+        fmul            v4.4s,  v0.4s,  v16.s[0]
+        fmul            v5.4s,  v1.4s,  v16.s[0]
+        fmul            v6.4s,  v2.4s,  v16.s[1]
+        fmul            v7.4s,  v3.4s,  v16.s[1]
+        st1             {v4.4s,v5.4s}, [x1], #32
+        st1             {v6.4s,v7.4s}, [x1], #32
+        subs            w5,  w5,  #2
+        b.gt            2b
+        b.eq            1f
+        ret
+1:
+        ld1             {v0.4s,v1.4s}, [x2]
+        ld1             {v16.s}[0],  [x3]
+        scvtf           v0.4s,  v0.4s
+        scvtf           v1.4s,  v1.4s
+        fmul            v4.4s,  v0.4s,  v16.s[0]
+        fmul            v5.4s,  v1.4s,  v16.s[0]
+        st1             {v4.4s,v5.4s}, [x1]
+        ret
+endfunc