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