105 lines
4.0 KiB
C++
105 lines
4.0 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 "nscore.h"
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#include "nsAlgorithm.h"
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#include <emmintrin.h>
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#include <nsUTF8Utils.h>
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void
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LossyConvertEncoding16to8::write_sse2(const char16_t* aSource,
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uint32_t aSourceLength)
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{
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char* dest = mDestination;
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// Align source to a 16-byte boundary.
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uint32_t i = 0;
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uint32_t alignLen =
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XPCOM_MIN<uint32_t>(aSourceLength,
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uint32_t(-NS_PTR_TO_INT32(aSource) & 0xf) / sizeof(char16_t));
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for (; i < alignLen; ++i) {
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dest[i] = static_cast<unsigned char>(aSource[i]);
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}
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// Walk 64 bytes (four XMM registers) at a time.
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__m128i vectmask = _mm_set1_epi16(0x00ff);
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for (; aSourceLength - i > 31; i += 32) {
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__m128i source1 = _mm_load_si128(reinterpret_cast<const __m128i*>(aSource + i));
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source1 = _mm_and_si128(source1, vectmask);
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__m128i source2 = _mm_load_si128(reinterpret_cast<const __m128i*>(aSource + i + 8));
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source2 = _mm_and_si128(source2, vectmask);
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__m128i source3 = _mm_load_si128(reinterpret_cast<const __m128i*>(aSource + i + 16));
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source3 = _mm_and_si128(source3, vectmask);
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__m128i source4 = _mm_load_si128(reinterpret_cast<const __m128i*>(aSource + i + 24));
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source4 = _mm_and_si128(source4, vectmask);
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// Pack the source data. SSE2 views this as a saturating uint16_t to
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// uint8_t conversion, but since we masked off the high-order byte of every
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// uint16_t, we're really just grabbing the low-order bytes of source1 and
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// source2.
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__m128i packed1 = _mm_packus_epi16(source1, source2);
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__m128i packed2 = _mm_packus_epi16(source3, source4);
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// This store needs to be unaligned since there's no guarantee that the
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// alignment we did above for the source will align the destination.
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_mm_storeu_si128(reinterpret_cast<__m128i*>(dest + i), packed1);
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_mm_storeu_si128(reinterpret_cast<__m128i*>(dest + i + 16), packed2);
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}
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// Finish up the rest.
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for (; i < aSourceLength; ++i) {
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dest[i] = static_cast<unsigned char>(aSource[i]);
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}
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mDestination += i;
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}
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void
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LossyConvertEncoding8to16::write_sse2(const char* aSource,
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uint32_t aSourceLength)
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{
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char16_t* dest = mDestination;
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// Align source to a 16-byte boundary. We choose to align source rather than
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// dest because we'd rather have our loads than our stores be fast. You have
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// to wait for a load to complete, but you can keep on moving after issuing a
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// store.
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uint32_t i = 0;
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uint32_t alignLen = XPCOM_MIN(aSourceLength,
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uint32_t(-NS_PTR_TO_INT32(aSource) & 0xf));
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for (; i < alignLen; ++i) {
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dest[i] = static_cast<unsigned char>(aSource[i]);
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}
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// Walk 32 bytes (two XMM registers) at a time.
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for (; aSourceLength - i > 31; i += 32) {
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__m128i source1 = _mm_load_si128(reinterpret_cast<const __m128i*>(aSource + i));
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__m128i source2 = _mm_load_si128(reinterpret_cast<const __m128i*>(aSource + i + 16));
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// Interleave 0s in with the bytes of source to create lo and hi.
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__m128i lo1 = _mm_unpacklo_epi8(source1, _mm_setzero_si128());
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__m128i hi1 = _mm_unpackhi_epi8(source1, _mm_setzero_si128());
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__m128i lo2 = _mm_unpacklo_epi8(source2, _mm_setzero_si128());
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__m128i hi2 = _mm_unpackhi_epi8(source2, _mm_setzero_si128());
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// store lo and hi into dest.
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_mm_storeu_si128(reinterpret_cast<__m128i*>(dest + i), lo1);
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_mm_storeu_si128(reinterpret_cast<__m128i*>(dest + i + 8), hi1);
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_mm_storeu_si128(reinterpret_cast<__m128i*>(dest + i + 16), lo2);
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_mm_storeu_si128(reinterpret_cast<__m128i*>(dest + i + 24), hi2);
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}
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// Finish up whatever's left.
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for (; i < aSourceLength; ++i) {
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dest[i] = static_cast<unsigned char>(aSource[i]);
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}
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mDestination += i;
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}
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