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removing some dead code #4

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Merged
lemire merged 3 commits into from
Feb 19, 2026
Merged

removing some dead code #4

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e440ffb
removing some dead code
lemire Feb 18, 2026
856aa8b
more dead
lemire Feb 18, 2026
df905a9
add back `write_four_digits_10000`
jaja360 Feb 19, 2026
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97 changes: 0 additions & 97 deletions src/digits.h
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Original file line number Diff line number Diff line change
Expand Up @@ -52,47 +52,6 @@ champagne_lemire_really_inline std::pair<uint64_t, uint64_t> div10e16(uint64_t x
return {q, r};
}

champagne_lemire_really_inline std::array<char, 2> get_one_digit_with_dot(uint32_t value) {
constexpr static std::array<std::array<char, 2>, 10> digit_table = []() {
std::array<std::array<char, 2>, 10> table;
for (int i = 0; i < 10; ++i) {
// Calculate the tens digit
table[i][0] = i + '0';
table[i][1] = '.';
}
return table;
}();
return digit_table[value];
}

champagne_lemire_really_inline std::array<char, 3> get_two_digits_with_dot(uint32_t value) {
constexpr static std::array<std::array<char, 3>, 100> hundreds_digit_table =
[]() {
std::array<std::array<char, 3>, 100> table{};
for (int i = 0; i < 100; ++i) {
table[i] = {static_cast<char>((i / 10) % 10 + '0'), '.',
static_cast<char>((i % 10) + '0')};
}
return table;
}();
return hundreds_digit_table[value];
}



champagne_lemire_really_inline std::array<char, 4> get_two_digits_with_dot_with_one_pad(uint32_t value) {
constexpr static std::array<std::array<char, 4>, 100> hundreds_digit_table =
[]() {
std::array<std::array<char, 4>, 100> table{};
for (int i = 0; i < 100; ++i) {
table[i] = {static_cast<char>((i / 10) % 10 + '0'), '.',
static_cast<char>((i % 10) + '0'), '0'}; // extra pad
}
return table;
}();
return hundreds_digit_table[value];
}

champagne_lemire_really_inline std::array<char, 2> get_two_digits_v(uint32_t value) {
constexpr static std::array<std::array<char, 2>, 256> hundreds_digit_table =
[]() {
Expand Down Expand Up @@ -121,68 +80,12 @@ champagne_lemire_really_inline std::array<char, 2> get_two_digits(uint32_t value
return hundreds_digit_table[value];
}

// We stop at 309 because that is the upper bound for the exponent in a double
champagne_lemire_really_inline std::array<char, 3> get_three_digits(uint32_t value) {
constexpr static std::array<std::array<char, 3>, 309> digit_table =
[]() {
std::array<std::array<char, 3>, 309> table;
for (int i = 0; i < 309; ++i) {
table[i][0] = (i / 100) + '0';
// Calculate the tens digit
table[i][1] = ((i / 10) % 10) + '0';
// Calculate the units digit
table[i][2] = (i % 10) + '0';
}
return table;
}();
return digit_table[value];
}

champagne_lemire_really_inline void write_one_digit_with_dot(char *buffer, uint32_t value) {
std::memcpy(buffer, get_one_digit_with_dot(value).data(), 2);
}

champagne_lemire_really_inline void write_two_digits_with_dot(char *buffer, uint32_t value) {
std::memcpy(buffer, get_two_digits_with_dot(value).data(), 3);
}

// writes two digits, a dot, and a padding zero, why the padding zero? because
// it is faster to copy four bytes than three bytes on most architectures.
champagne_lemire_really_inline void write_two_digits_with_dot_with_one_pad(char *buffer, uint32_t value) {
std::memcpy(buffer, get_two_digits_with_dot_with_one_pad(value).data(), 4);
}

champagne_lemire_really_inline void write_two_digits(char *buffer, uint32_t value) {
std::memcpy(buffer, get_two_digits(value).data(), 2);
}

champagne_lemire_really_inline void write_two_digits_v(char *buffer, uint32_t value) {
std::memcpy(buffer, get_two_digits_v(value).data(), 2);
}

champagne_lemire_really_inline void write_three_digits(char *buffer, uint32_t value) {
std::memcpy(buffer, get_three_digits(value).data(), 3);
}

champagne_lemire_really_inline void write_four_digits_10000(char *buffer, uint64_t value) {
auto [high, low] = div100v(value);
std::memcpy(buffer, get_two_digits(high).data(), 2);
std::memcpy(buffer + 2, get_two_digits_v(low).data(), 2);
}

champagne_lemire_really_inline char* write_three_or_four_digits_10000(char *buffer, uint64_t value) {
auto [high, low] = div100v(value);
if (value < 1000) {
buffer[0] = char('0' + high);
std::memcpy(buffer + 1, get_two_digits_v(low).data(), 2);
return buffer + 3;
} else {
std::memcpy(buffer, get_two_digits(high).data(), 2);
std::memcpy(buffer + 2, get_two_digits_v(low).data(), 2);
return buffer + 4;
}
}

champagne_lemire_really_inline char* write_one_two_three_or_four_digits_10000(char *buffer, uint64_t value) {
if(value >= 1000) { // four digits
const auto [high, low] = div100v(value);
Expand Down
1 change: 0 additions & 1 deletion src/ifma_avx512.h
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Expand Up @@ -92,7 +92,6 @@ champagne_lemire_really_inline __m512i to_string_avx512ifma_8digits(uint64_t n)
twoto52 / 100000000, twoto52 / 10000000, twoto52 / 1000000, twoto52 / 100000,
twoto52 / 10000, twoto52 / 1000, twoto52 / 100, twoto52 / 10
);
__m512i zmmzero = _mm512_castsi128_si512(_mm_cvtsi64_si128(0x01A1A400));
__m512i zmmTen = _mm512_set1_epi64(10);
__m512i asciiZero = _mm512_set1_epi64('0');
__m512i lowbits_l = _mm512_madd52lo_epu64(ifma_const, bcstq_l, ifma_const); // ifma_const * bcstq_l + ifma_const
Expand Down