70 lines
2.0 KiB
C++
70 lines
2.0 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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#include <emmintrin.h>
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#include "nsReadableUtilsImpl.h"
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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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FirstNonASCII(const char16_t* aBegin, const char16_t* aEnd)
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{
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const size_t kNumUnicharsPerVector = sizeof(__m128i) / sizeof(char16_t);
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typedef NonASCIIParameters<sizeof(size_t)> p;
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const size_t kMask = p::mask();
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const uintptr_t kXmmAlignMask = 0xf;
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const uint16_t kShortMask = 0xff80;
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const size_t kNumUnicharsPerWord = p::numUnicharsPerWord();
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const char16_t* idx = aBegin;
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// Align ourselves to a 16-byte boundary as required by _mm_load_si128
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for (; idx != aEnd && ((uintptr_t(idx) & kXmmAlignMask) != 0); idx++) {
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if (!IsASCII(*idx)) {
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return idx - aBegin;
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}
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}
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// Check one XMM register (16 bytes) at a time.
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const char16_t* vectWalkEnd = aligned(aEnd, kXmmAlignMask);
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__m128i vectmask = _mm_set1_epi16(static_cast<int16_t>(kShortMask));
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for (; idx != vectWalkEnd; idx += kNumUnicharsPerVector) {
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const __m128i vect = *reinterpret_cast<const __m128i*>(idx);
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if (!is_zero(_mm_and_si128(vect, vectmask))) {
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return idx - aBegin;
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}
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}
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// Check one word at a time.
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const char16_t* wordWalkEnd = aligned(aEnd, p::alignMask());
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for(; idx != wordWalkEnd; idx += kNumUnicharsPerWord) {
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const size_t word = *reinterpret_cast<const size_t*>(idx);
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if (word & kMask) {
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return idx - aBegin;
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}
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}
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// Take care of the remainder one character at a time.
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for (; idx != aEnd; idx++) {
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if (!IsASCII(*idx)) {
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return idx - aBegin;
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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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