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// file included directly
template <endianness big_endian>
size_t icelake_convert_latin1_to_utf16(const char *latin1_input, size_t len,
char16_t *utf16_output) {
size_t rounded_len = len & ~0x1F; // Round down to nearest multiple of 32
__m512i byteflip = _mm512_setr_epi64(0x0607040502030001, 0x0e0f0c0d0a0b0809,
0x0607040502030001, 0x0e0f0c0d0a0b0809,
0x0607040502030001, 0x0e0f0c0d0a0b0809,
0x0607040502030001, 0x0e0f0c0d0a0b0809);
for (size_t i = 0; i < rounded_len; i += 32) {
// Load 32 Latin1 characters into a 256-bit register
__m256i in = _mm256_loadu_si256((__m256i *)&latin1_input[i]);
// Zero extend each set of 8 Latin1 characters to 32 16-bit integers
__m512i out = _mm512_cvtepu8_epi16(in);
if (big_endian) {
out = _mm512_shuffle_epi8(out, byteflip);
}
// Store the results back to memory
_mm512_storeu_si512((__m512i *)&utf16_output[i], out);
}
if (rounded_len != len) {
uint32_t mask = uint32_t(1 << (len - rounded_len)) - 1;
__m256i in = _mm256_maskz_loadu_epi8(mask, latin1_input + rounded_len);
// Zero extend each set of 8 Latin1 characters to 32 16-bit integers
__m512i out = _mm512_cvtepu8_epi16(in);
if (big_endian) {
out = _mm512_shuffle_epi8(out, byteflip);
}
// Store the results back to memory
_mm512_mask_storeu_epi16(utf16_output + rounded_len, mask, out);
}
return len;
}
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