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Optimize char16_t parsing for digit_comparison.h

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This commit is contained in:
Maya Warrier 2023-04-02 00:32:30 -04:00
parent 2d57c09530
commit cda25408bc
1 changed files with 36 additions and 23 deletions
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59
include/fast_float/ascii_number.h
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@ -120,27 +120,56 @@ uint32_t parse_eight_digits_unrolled(uint64_t val) {
return uint32_t(val);
}
// http://0x80.pl/articles/simd-parsing-int-sequences.html
#if FASTFLOAT_SSE2
fastfloat_really_inline
uint32_t parse_eight_digits_unrolled_c16(const __m128i val) {
// x - '0'
const __m128i s1digits16 = _mm_sub_epi16(val, _mm_set1_epi16('0'));
// 10 * x(b) + x(b-1) -> 2 digit numbers
const __m128i s2digits32 = _mm_madd_epi16(s1digits16, _mm_setr_epi16(10, 1, 10, 1, 10, 1, 10, 1));
const __m128i s2digits16 = _mm_packus_epi16(s2digits32, s2digits32);
// 100 * x(b) + x(b-1) -> 4 digit numbers
const __m128i s4digits32 = _mm_madd_epi16(s2digits16, _mm_setr_epi16(100, 1, 100, 1, 100, 1, 100, 1));
const __m128i s4digits16 = _mm_packus_epi16(s4digits32, s4digits32);
// 10000 * x(b) + x(b-1) -> 8 digit number
const __m128i s8digits32 = _mm_madd_epi16(s4digits16, _mm_setr_epi16(10000, 1, 10000, 1, 10000, 1, 10000, 1));
uint32_t value;
_mm_storeu_si32(&value, s8digits32);
return value;
}
#endif
// credit @aqrit
fastfloat_really_inline constexpr bool is_made_of_eight_digits_fast(uint64_t val) noexcept {
return !((((val + 0x4646464646464646) | (val - 0x3030303030303030)) &
0x8080808080808080));
}
template <typename CharT>
fastfloat_really_inline FASTFLOAT_CONSTEXPR20
uint32_t parse_eight_digits_unrolled(const CharT* chars) noexcept {
uint32_t parse_eight_digits_unrolled(const char* chars) noexcept {
return parse_eight_digits_unrolled(read_u64(chars));
}
fastfloat_really_inline FASTFLOAT_CONSTEXPR20
bool is_made_of_eight_digits_fast(const char *chars) noexcept {
return is_made_of_eight_digits_fast(read_u64(chars));
uint32_t parse_eight_digits_unrolled(const char16_t* chars) noexcept {
if (cpp20_and_in_constexpr() || !has_simd()) {
return parse_eight_digits_unrolled(read_u64(chars));
}
#if !FASTFLOAT_SSE2
return 0; // never reaches here, satisfy compiler
#else
FASTFLOAT_SIMD_DISABLE_WARNINGS
return parse_eight_digits_unrolled_c16(_mm_loadu_si128(reinterpret_cast<const __m128i*>(chars)));
FASTFLOAT_SIMD_RESTORE_WARNINGS
#endif
}
fastfloat_really_inline FASTFLOAT_CONSTEXPR20
bool parse_if_eight_digits_unrolled(const char* chars, std::uint64_t& i) noexcept {
const bool all = is_made_of_eight_digits_fast(chars);
if (all) i = i * 100000000 + parse_eight_digits_unrolled(chars);
const bool all = is_made_of_eight_digits_fast(read_u64(chars));
if (all) i = i * 100000000 + parse_eight_digits_unrolled(read_u64(chars));
return all;
}
@ -160,28 +189,13 @@ bool parse_if_eight_digits_unrolled(const char16_t* chars, std::uint64_t& i) noe
#else
FASTFLOAT_SIMD_DISABLE_WARNINGS
const __m128i data = _mm_loadu_si128(reinterpret_cast<const __m128i*>(chars));
// (x - '0') <= 9
const __m128i t0 = _mm_sub_epi16(data, _mm_set1_epi16(80));
const __m128i t1 = _mm_cmpgt_epi16(t0, _mm_set1_epi16(-119));
const bool is_digits = _mm_movemask_epi8(t1) == 0;
if (is_digits) {
// x - '0'
const __m128i s1digits16 = _mm_sub_epi16(data, _mm_set1_epi16('0'));
// 10 * x(b) + x(b-1) -> 2 digit numbers
const __m128i s2digits32 = _mm_madd_epi16(s1digits16, _mm_setr_epi16(10, 1, 10, 1, 10, 1, 10, 1));
const __m128i s2digits16 = _mm_packus_epi16(s2digits32, s2digits32);
// 100 * x(b) + x(b-1) -> 4 digit numbers
const __m128i s4digits32 = _mm_madd_epi16(s2digits16, _mm_setr_epi16(100, 1, 100, 1, 100, 1, 100, 1));
const __m128i s4digits16 = _mm_packus_epi16(s4digits32, s4digits32);
// 10000 * x(b) + x(b-1) -> 8 digit number
const __m128i s8digits32 = _mm_madd_epi16(s4digits16, _mm_setr_epi16(10000, 1, 10000, 1, 10000, 1, 10000, 1));
uint32_t value;
_mm_storeu_si32(&value, s8digits32);
i = i * 100000000 + value;
i = i * 100000000 + parse_eight_digits_unrolled_c16(data);
return true;
}
else return false;
@ -190,7 +204,6 @@ FASTFLOAT_SIMD_RESTORE_WARNINGS
}
typedef span<const char> byte_span;
template <typename CharT>