Import aom library

This is the reference implementation for the Alliance for Open Media's av1 video code.

The commit used was 4d668d7feb1f8abd809d1bca0418570a7f142a36.

third_party/aom/aom_dsp/arm/aom_convolve_neon.c

@@ -0,0 +1,66 @@
+/*
+ * Copyright (c) 2016, Alliance for Open Media. All rights reserved
+ *
+ * This source code is subject to the terms of the BSD 2 Clause License and
+ * the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License
+ * was not distributed with this source code in the LICENSE file, you can
+ * obtain it at www.aomedia.org/license/software. If the Alliance for Open
+ * Media Patent License 1.0 was not distributed with this source code in the
+ * PATENTS file, you can obtain it at www.aomedia.org/license/patent.
+ */
+
+#include <assert.h>
+
+#include "./aom_dsp_rtcd.h"
+#include "aom_dsp/aom_dsp_common.h"
+#include "aom_ports/mem.h"
+
+void aom_convolve8_neon(const uint8_t *src, ptrdiff_t src_stride, uint8_t *dst,
+                        ptrdiff_t dst_stride, const int16_t *filter_x,
+                        int x_step_q4, const int16_t *filter_y, int y_step_q4,
+                        int w, int h) {
+  /* Given our constraints: w <= 64, h <= 64, taps == 8 we can reduce the
+   * maximum buffer size to 64 * 64 + 7 (+ 1 to make it divisible by 4).
+   */
+  DECLARE_ALIGNED(8, uint8_t, temp[64 * 72]);
+
+  // Account for the vertical phase needing 3 lines prior and 4 lines post
+  int intermediate_height = h + 7;
+
+  assert(y_step_q4 == 16);
+  assert(x_step_q4 == 16);
+
+  /* Filter starting 3 lines back. The neon implementation will ignore the
+   * given height and filter a multiple of 4 lines. Since this goes in to
+   * the temp buffer which has lots of extra room and is subsequently discarded
+   * this is safe if somewhat less than ideal.
+   */
+  aom_convolve8_horiz_neon(src - src_stride * 3, src_stride, temp, 64, filter_x,
+                           x_step_q4, filter_y, y_step_q4, w,
+                           intermediate_height);
+
+  /* Step into the temp buffer 3 lines to get the actual frame data */
+  aom_convolve8_vert_neon(temp + 64 * 3, 64, dst, dst_stride, filter_x,
+                          x_step_q4, filter_y, y_step_q4, w, h);
+}
+
+void aom_convolve8_avg_neon(const uint8_t *src, ptrdiff_t src_stride,
+                            uint8_t *dst, ptrdiff_t dst_stride,
+                            const int16_t *filter_x, int x_step_q4,
+                            const int16_t *filter_y, int y_step_q4, int w,
+                            int h) {
+  DECLARE_ALIGNED(8, uint8_t, temp[64 * 72]);
+  int intermediate_height = h + 7;
+
+  assert(y_step_q4 == 16);
+  assert(x_step_q4 == 16);
+
+  /* This implementation has the same issues as above. In addition, we only want
+   * to average the values after both passes.
+   */
+  aom_convolve8_horiz_neon(src - src_stride * 3, src_stride, temp, 64, filter_x,
+                           x_step_q4, filter_y, y_step_q4, w,
+                           intermediate_height);
+  aom_convolve8_avg_vert_neon(temp + 64 * 3, 64, dst, dst_stride, filter_x,
+                              x_step_q4, filter_y, y_step_q4, w, h);
+}