1 files changed, 83 insertions, 0 deletions
diff --git a/gfx/2d/SwizzleAVX2.cpp b/gfx/2d/SwizzleAVX2.cpp
new file mode 100644
index 0000000000..fe8fbf4530
--- /dev/null
+++ b/gfx/2d/SwizzleAVX2.cpp
@@ -0,0 +1,83 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "Swizzle.h"
+
+#include <immintrin.h>
+#include <tmmintrin.h>
+
+namespace mozilla::gfx {
+
+template <bool aSwapRB>
+void UnpackRowRGB24_SSSE3(const uint8_t* aSrc, uint8_t* aDst, int32_t aLength);
+
+template <bool aSwapRB>
+void UnpackRowRGB24_AVX2(const uint8_t* aSrc, uint8_t* aDst, int32_t aLength) {
+  // Because this implementation will read an additional 8 bytes of data that
+  // is ignored and masked over, we cannot use the accelerated version for the
+  // last 1-10 pixels (3-30 bytes remaining) to guarantee we don't access memory
+  // outside the buffer (we read in 32 byte chunks).
+  if (aLength < 11) {
+    UnpackRowRGB24_SSSE3<aSwapRB>(aSrc, aDst, aLength);
+    return;
+  }
+
+  // Because we are expanding, we can only process the data back to front in
+  // case we are performing this in place.
+  int32_t alignedRow = (aLength - 4) & ~7;
+  int32_t remainder = aLength - alignedRow;
+
+  const uint8_t* src = aSrc + alignedRow * 3;
+  uint8_t* dst = aDst + alignedRow * 4;
+
+  // Handle any 3-10 remaining pixels.
+  UnpackRowRGB24_SSSE3<aSwapRB>(src, dst, remainder);
+
+  // Used to shuffle the two final 32-bit words which we ignore into the last
+  // 32-bit word of each 128-bit lane, such that
+  //   RGBR GBRG BRGB RGBR GBRG BRGB RGBR GBRG
+  //   BRGB RGBR GBRG BRGB ZZZZ ZZZZ ZZZZ ZZZZ
+  // becomes
+  //   RGBR GBRG BRGB RGBR GBRG BRGB ZZZZ ZZZZ
+  //   RGBR GBRG BRGB RGBR GBRG BRGB ZZZZ ZZZZ
+  const __m256i discardMask = _mm256_set_epi32(7, 5, 4, 3, 6, 2, 1, 0);
+
+  // Used to shuffle 8-bit words within a 128-bit lane, such that we transform
+  //   RGBR GBRG BRGB RGBR GBRG BRGB ZZZZ ZZZZ
+  // into
+  //   RGBZ RGBZ RGBZ RGBZ RGBZ RGBZ RGBZ RGBZ
+  // or
+  //   BGRZ BGRZ BGRZ BGRZ BGRZ BGRZ BGRZ BGRZ
+  const __m256i colorMask =
+      aSwapRB ? _mm256_set_epi8(15, 9, 10, 11, 14, 6, 7, 8, 13, 3, 4, 5, 12, 0,
+                                1, 2, 15, 9, 10, 11, 14, 6, 7, 8, 13, 3, 4, 5,
+                                12, 0, 1, 2)
+              : _mm256_set_epi8(15, 11, 10, 9, 14, 8, 7, 6, 13, 5, 4, 3, 12, 2,
+                                1, 0, 15, 11, 10, 9, 14, 8, 7, 6, 13, 5, 4, 3,
+                                12, 2, 1, 0);
+
+  // Used to transform RGBZ/BGRZ to RGBX/BGRX, or force the alpha opaque.
+  const __m256i alphaMask = _mm256_set1_epi32(0xFF000000);
+
+  // Process all 8-pixel chunks as one vector.
+  src -= 8 * 3;
+  dst -= 8 * 4;
+  while (src >= aSrc) {
+    __m256i px = _mm256_loadu_si256(reinterpret_cast<const __m256i*>(src));
+    px = _mm256_permutevar8x32_epi32(px, discardMask);
+    px = _mm256_shuffle_epi8(px, colorMask);
+    px = _mm256_or_si256(px, alphaMask);
+    _mm256_storeu_si256(reinterpret_cast<__m256i*>(dst), px);
+    src -= 8 * 3;
+    dst -= 8 * 4;
+  }
+}
+
+// Force instantiation of swizzle variants here.
+template void UnpackRowRGB24_AVX2<false>(const uint8_t*, uint8_t*, int32_t);
+template void UnpackRowRGB24_AVX2<true>(const uint8_t*, uint8_t*, int32_t);
+
+}  // namespace mozilla::gfx