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111 lines
3.1 KiB
C
111 lines
3.1 KiB
C
static inline int
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dec_loop_avx2_inner (const uint8_t **s, uint8_t **o, size_t *rounds)
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{
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const __m256i lut_lo = _mm256_setr_epi8(
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0x15, 0x11, 0x11, 0x11, 0x11, 0x11, 0x11, 0x11,
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0x11, 0x11, 0x13, 0x1A, 0x1B, 0x1B, 0x1B, 0x1A,
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0x15, 0x11, 0x11, 0x11, 0x11, 0x11, 0x11, 0x11,
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0x11, 0x11, 0x13, 0x1A, 0x1B, 0x1B, 0x1B, 0x1A);
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const __m256i lut_hi = _mm256_setr_epi8(
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0x10, 0x10, 0x01, 0x02, 0x04, 0x08, 0x04, 0x08,
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0x10, 0x10, 0x10, 0x10, 0x10, 0x10, 0x10, 0x10,
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0x10, 0x10, 0x01, 0x02, 0x04, 0x08, 0x04, 0x08,
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0x10, 0x10, 0x10, 0x10, 0x10, 0x10, 0x10, 0x10);
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const __m256i lut_roll = _mm256_setr_epi8(
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0, 16, 19, 4, -65, -65, -71, -71,
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0, 0, 0, 0, 0, 0, 0, 0,
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0, 16, 19, 4, -65, -65, -71, -71,
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0, 0, 0, 0, 0, 0, 0, 0);
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const __m256i mask_2F = _mm256_set1_epi8(0x2F);
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// Load input:
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__m256i str = _mm256_loadu_si256((__m256i *) *s);
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// See the SSSE3 decoder for an explanation of the algorithm.
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const __m256i hi_nibbles = _mm256_and_si256(_mm256_srli_epi32(str, 4), mask_2F);
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const __m256i lo_nibbles = _mm256_and_si256(str, mask_2F);
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const __m256i hi = _mm256_shuffle_epi8(lut_hi, hi_nibbles);
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const __m256i lo = _mm256_shuffle_epi8(lut_lo, lo_nibbles);
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if (!_mm256_testz_si256(lo, hi)) {
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return 0;
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}
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const __m256i eq_2F = _mm256_cmpeq_epi8(str, mask_2F);
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const __m256i roll = _mm256_shuffle_epi8(lut_roll, _mm256_add_epi8(eq_2F, hi_nibbles));
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// Now simply add the delta values to the input:
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str = _mm256_add_epi8(str, roll);
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// Reshuffle the input to packed 12-byte output format:
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str = dec_reshuffle(str);
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// Store the output:
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_mm256_storeu_si256((__m256i *) *o, str);
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*s += 32;
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*o += 24;
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*rounds -= 1;
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return 1;
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}
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static inline void
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dec_loop_avx2 (const uint8_t **s, size_t *slen, uint8_t **o, size_t *olen)
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{
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if (*slen < 45) {
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return;
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}
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// Process blocks of 32 bytes per round. Because 8 extra zero bytes are
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// written after the output, ensure that there will be at least 13
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// bytes of input data left to cover the gap. (11 data bytes and up to
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// two end-of-string markers.)
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size_t rounds = (*slen - 13) / 32;
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*slen -= rounds * 32; // 32 bytes consumed per round
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*olen += rounds * 24; // 24 bytes produced per round
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do {
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if (rounds >= 8) {
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if (dec_loop_avx2_inner(s, o, &rounds) &&
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dec_loop_avx2_inner(s, o, &rounds) &&
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dec_loop_avx2_inner(s, o, &rounds) &&
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dec_loop_avx2_inner(s, o, &rounds) &&
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dec_loop_avx2_inner(s, o, &rounds) &&
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dec_loop_avx2_inner(s, o, &rounds) &&
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dec_loop_avx2_inner(s, o, &rounds) &&
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dec_loop_avx2_inner(s, o, &rounds)) {
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continue;
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}
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break;
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}
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if (rounds >= 4) {
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if (dec_loop_avx2_inner(s, o, &rounds) &&
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dec_loop_avx2_inner(s, o, &rounds) &&
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dec_loop_avx2_inner(s, o, &rounds) &&
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dec_loop_avx2_inner(s, o, &rounds)) {
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continue;
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}
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break;
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}
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if (rounds >= 2) {
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if (dec_loop_avx2_inner(s, o, &rounds) &&
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dec_loop_avx2_inner(s, o, &rounds)) {
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continue;
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}
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break;
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}
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dec_loop_avx2_inner(s, o, &rounds);
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break;
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} while (rounds > 0);
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// Adjust for any rounds that were skipped:
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*slen += rounds * 32;
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*olen -= rounds * 24;
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}
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