DetilePlane and unittest for NEON

Bug: libyuv:915, b/215425056
Change-Id: Iccab1ed3f6d385f02895d44faa94d198ad79d693
Reviewed-on: https://chromium-review.googlesource.com/c/libyuv/libyuv/+/3424820
Reviewed-by: Justin Green <greenjustin@google.com>
Reviewed-by: Frank Barchard <fbarchard@chromium.org>
Commit-Queue: Frank Barchard <fbarchard@chromium.org>

1 files changed, 47 insertions, 0 deletions

diff --git a/source/planar_functions.cc b/source/planar_functions.cc
index 4147cfbb..d7cb8dc7 100644
--- a/source/planar_functions.cc
+++ b/source/planar_functions.cc
@@ -853,6 +853,53 @@ int NV21ToNV12(const uint8_t* src_y,
   return 0;
 }
 
+// Detile a plane of data
+// tile width is 16 and assumed.
+// tile_height is 16 or 32 for MM21.
+// src_stride_y is bytes per row of source ignoring tiling. e.g. 640
+// TODO: More detile row functions.
+
+LIBYUV_API
+void DetilePlane(const uint8_t* src_y,
+                 int src_stride_y,
+                 uint8_t* dst_y,
+                 int dst_stride_y,
+                 int width,
+                 int height,
+                 int tile_height) {
+  const ptrdiff_t src_tile_stride = 16 * tile_height;
+  int y;
+  void (*DetileRow)(const uint8_t* src, ptrdiff_t src_tile_stride, uint8_t* dst,
+                    int width) = DetileRow_C;
+  assert(src_stride_y >= 0);
+  assert(tile_height > 0);
+  assert(src_stride_y > 0);
+
+  // Negative height means invert the image.
+  if (height < 0) {
+    height = -height;
+    dst_y = dst_y + (height - 1) * dst_stride_y;
+    dst_stride_y = -dst_stride_y;
+  }
+
+#if defined(HAS_DETILEROW_NEON)
+  if (TestCpuFlag(kCpuHasNEON) && IS_ALIGNED(width, 16)) {
+    DetileRow = DetileRow_NEON;
+  }
+#endif
+
+  // Detile plane
+  for (y = 0; y < height; ++y) {
+    DetileRow(src_y, src_tile_stride, dst_y, width);
+    dst_y += dst_stride_y;
+    src_y += 16;
+    // Advance to next row of tiles.
+    if ((y & (tile_height - 1)) == (tile_height - 1)) {
+      src_y = src_y - src_tile_stride + src_stride_y * tile_height;
+    }
+  }
+}
+
 // Support function for NV12 etc RGB channels.
 // Width and height are plane sizes (typically half pixel width).
 LIBYUV_API