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Use SSE intrinsics for uint64_t byte swapping

This commit is contained in:
raven02 2015-07-02 23:26:02 +08:00
parent fcf89a61e7
commit 3ce6e0ccd8
1 changed files with 28 additions and 1 deletions
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29
src/xenia/base/memory_generic.cc
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@ -100,7 +100,34 @@ void copy_and_swap_64_aligned(uint64_t* dest, const uint64_t* src,
void copy_and_swap_64_unaligned(uint64_t* dest, const uint64_t* src,
size_t count) {
for (size_t i = 0; i < count; ++i) {
size_t i;
__m128i input, byte1, byte2, byte3, byte4, output;
__m128i byte2mask = _mm_set1_epi32(0x00FF0000);
__m128i byte3mask = _mm_set1_epi32(0x0000FF00);
for (i = 0; i + 2 <= count; i += 2) {
input = _mm_loadu_si128((__m128i*)&src[i]);
// Do the four shifts
byte1 = _mm_slli_epi32(input, 24);
byte2 = _mm_slli_epi32(input, 8);
byte3 = _mm_srli_epi32(input, 8);
byte4 = _mm_srli_epi32(input, 24);
// Or bytes together
output = _mm_or_si128(byte1, byte4);
byte2 = _mm_and_si128(byte2, byte2mask);
output = _mm_or_si128(output, byte2);
byte3 = _mm_and_si128(byte3, byte3mask);
output = _mm_or_si128(output, byte3);
// Reorder the two words
output = _mm_shuffle_epi32(output, _MM_SHUFFLE(2, 3, 0, 1));
_mm_storeu_si128((__m128i*)&dest[i], output);
}
for (; i < count; ++i) { // handle residual elements
dest[i] = byte_swap(src[i]);
}
}