74 lines
2.1 KiB
C++
74 lines
2.1 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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// This file should only be compiled if you're on x86 or x86_64. Additionally,
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// you'll need to compile this file with -msse2 if you're using gcc.
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#include <emmintrin.h>
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#include "nscore.h"
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#include "nsAlgorithm.h"
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#include "nsTextFragmentImpl.h"
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#include <algorithm>
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namespace mozilla {
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namespace SSE2 {
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static inline bool
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is_zero (__m128i x)
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{
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return
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_mm_movemask_epi8(_mm_cmpeq_epi8(x, _mm_setzero_si128())) == 0xffff;
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}
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int32_t
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FirstNon8Bit(const char16_t *str, const char16_t *end)
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{
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const uint32_t numUnicharsPerVector = 8;
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typedef Non8BitParameters<sizeof(size_t)> p;
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const size_t mask = p::mask();
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const uint32_t numUnicharsPerWord = p::numUnicharsPerWord();
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const int32_t len = end - str;
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int32_t i = 0;
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// Align ourselves to a 16-byte boundary, as required by _mm_load_si128
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// (i.e. MOVDQA).
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int32_t alignLen =
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std::min(len, int32_t(((-NS_PTR_TO_INT32(str)) & 0xf) / sizeof(char16_t)));
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for (; i < alignLen; i++) {
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if (str[i] > 255)
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return i;
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}
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// Check one XMM register (16 bytes) at a time.
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const int32_t vectWalkEnd = ((len - i) / numUnicharsPerVector) * numUnicharsPerVector;
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const uint16_t shortMask = 0xff00;
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__m128i vectmask = _mm_set1_epi16(static_cast<int16_t>(shortMask));
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for(; i < vectWalkEnd; i += numUnicharsPerVector) {
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const __m128i vect = *reinterpret_cast<const __m128i*>(str + i);
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if (!is_zero(_mm_and_si128(vect, vectmask)))
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return i;
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}
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// Check one word at a time.
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const int32_t wordWalkEnd = ((len - i) / numUnicharsPerWord) * numUnicharsPerWord;
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for(; i < wordWalkEnd; i += numUnicharsPerWord) {
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const size_t word = *reinterpret_cast<const size_t*>(str + i);
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if (word & mask)
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return i;
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}
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// Take care of the remainder one character at a time.
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for (; i < len; i++) {
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if (str[i] > 255) {
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return i;
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}
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}
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return -1;
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}
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} // namespace SSE2
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} // namespace mozilla
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