1 files changed, 65 insertions, 0 deletions
diff --git a/dom/base/nsTextFragmentSSE2.cpp b/dom/base/nsTextFragmentSSE2.cpp
new file mode 100644
index 0000000000..c634717457
--- /dev/null
+++ b/dom/base/nsTextFragmentSSE2.cpp
@@ -0,0 +1,65 @@
+/* -*- 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/. */
+
+// This file should only be compiled if you're on x86 or x86_64.  Additionally,
+// you'll need to compile this file with -msse2 if you're using gcc.
+
+#include <emmintrin.h>
+#include "nscore.h"
+#include "nsTextFragmentImpl.h"
+#include <algorithm>
+
+namespace mozilla::SSE2 {
+
+static inline bool is_zero(__m128i x) {
+  return _mm_movemask_epi8(_mm_cmpeq_epi8(x, _mm_setzero_si128())) == 0xffff;
+}
+
+int32_t FirstNon8Bit(const char16_t* str, const char16_t* end) {
+  const uint32_t numUnicharsPerVector = 8;
+  using p = Non8BitParameters<sizeof(size_t)>;
+  const size_t mask = p::mask();
+  const uint32_t numUnicharsPerWord = p::numUnicharsPerWord();
+  const int32_t len = end - str;
+  int32_t i = 0;
+
+  // Align ourselves to a 16-byte boundary, as required by _mm_load_si128
+  // (i.e. MOVDQA).
+  int32_t alignLen = std::min(
+      len, int32_t(((-NS_PTR_TO_INT32(str)) & 0xf) / sizeof(char16_t)));
+  for (; i < alignLen; i++) {
+    if (str[i] > 255) return i;
+  }
+
+  // Check one XMM register (16 bytes) at a time.
+  const int32_t vectWalkEnd =
+      ((len - i) / numUnicharsPerVector) * numUnicharsPerVector;
+  const uint16_t shortMask = 0xff00;
+  __m128i vectmask = _mm_set1_epi16(static_cast<int16_t>(shortMask));
+  for (; i < vectWalkEnd; i += numUnicharsPerVector) {
+    const __m128i vect = *reinterpret_cast<const __m128i*>(str + i);
+    if (!is_zero(_mm_and_si128(vect, vectmask))) return i;
+  }
+
+  // Check one word at a time.
+  const int32_t wordWalkEnd =
+      ((len - i) / numUnicharsPerWord) * numUnicharsPerWord;
+  for (; i < wordWalkEnd; i += numUnicharsPerWord) {
+    const size_t word = *reinterpret_cast<const size_t*>(str + i);
+    if (word & mask) return i;
+  }
+
+  // Take care of the remainder one character at a time.
+  for (; i < len; i++) {
+    if (str[i] > 255) {
+      return i;
+    }
+  }
+
+  return -1;
+}
+
+}  // namespace mozilla::SSE2