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ULib/tests/ulib/branchlut.h
stefanocasazza e0f5b65442 sync
2020-02-11 18:38:45 +01:00

286 lines
9.1 KiB
C

#pragma once
// Function Time (ns) Speedup
// sprintf 194.225 1.00x
// ...
// branchlut 8.430 23.04x
// sse2 7.614 25.51x
// sse2 only faster above 9 digits
#include <stdint.h>
const char gDigitsLut[200] = {
'0','0','0','1','0','2','0','3','0','4','0','5','0','6','0','7','0','8','0','9',
'1','0','1','1','1','2','1','3','1','4','1','5','1','6','1','7','1','8','1','9',
'2','0','2','1','2','2','2','3','2','4','2','5','2','6','2','7','2','8','2','9',
'3','0','3','1','3','2','3','3','3','4','3','5','3','6','3','7','3','8','3','9',
'4','0','4','1','4','2','4','3','4','4','4','5','4','6','4','7','4','8','4','9',
'5','0','5','1','5','2','5','3','5','4','5','5','5','6','5','7','5','8','5','9',
'6','0','6','1','6','2','6','3','6','4','6','5','6','6','6','7','6','8','6','9',
'7','0','7','1','7','2','7','3','7','4','7','5','7','6','7','7','7','8','7','9',
'8','0','8','1','8','2','8','3','8','4','8','5','8','6','8','7','8','8','8','9',
'9','0','9','1','9','2','9','3','9','4','9','5','9','6','9','7','9','8','9','9'
};
// Branching for different cases (forward)
// Use lookup table of two digits
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wmissing-declarations"
char* u32toa_branchlut(uint32_t value, char* buffer) {
if (value < 10000) {
const uint32_t d1 = (value / 100) << 1;
const uint32_t d2 = (value % 100) << 1;
if (value >= 1000)
*buffer++ = gDigitsLut[d1];
if (value >= 100)
*buffer++ = gDigitsLut[d1 + 1];
if (value >= 10)
*buffer++ = gDigitsLut[d2];
*buffer++ = gDigitsLut[d2 + 1];
}
else if (value < 100000000) {
// value = bbbbcccc
const uint32_t b = value / 10000;
const uint32_t c = value % 10000;
const uint32_t d1 = (b / 100) << 1;
const uint32_t d2 = (b % 100) << 1;
const uint32_t d3 = (c / 100) << 1;
const uint32_t d4 = (c % 100) << 1;
if (value >= 10000000)
*buffer++ = gDigitsLut[d1];
if (value >= 1000000)
*buffer++ = gDigitsLut[d1 + 1];
if (value >= 100000)
*buffer++ = gDigitsLut[d2];
*buffer++ = gDigitsLut[d2 + 1];
*buffer++ = gDigitsLut[d3];
*buffer++ = gDigitsLut[d3 + 1];
*buffer++ = gDigitsLut[d4];
*buffer++ = gDigitsLut[d4 + 1];
}
else {
// value = aabbbbcccc in decimal
const uint32_t a = value / 100000000; // 1 to 42
value %= 100000000;
if (a >= 10) {
const unsigned i = a << 1;
*buffer++ = gDigitsLut[i];
*buffer++ = gDigitsLut[i + 1];
}
else
*buffer++ = '0' + static_cast<char>(a);
const uint32_t b = value / 10000; // 0 to 9999
const uint32_t c = value % 10000; // 0 to 9999
const uint32_t d1 = (b / 100) << 1;
const uint32_t d2 = (b % 100) << 1;
const uint32_t d3 = (c / 100) << 1;
const uint32_t d4 = (c % 100) << 1;
*buffer++ = gDigitsLut[d1];
*buffer++ = gDigitsLut[d1 + 1];
*buffer++ = gDigitsLut[d2];
*buffer++ = gDigitsLut[d2 + 1];
*buffer++ = gDigitsLut[d3];
*buffer++ = gDigitsLut[d3 + 1];
*buffer++ = gDigitsLut[d4];
*buffer++ = gDigitsLut[d4 + 1];
}
*buffer++ = '\0';
return buffer;
}
void i32toa_branchlut(int32_t value, char* buffer) {
uint32_t u = static_cast<uint32_t>(value);
if (value < 0) {
*buffer++ = '-';
u = ~u + 1;
}
u32toa_branchlut(u, buffer);
}
char* u64toa_branchlut(uint64_t value, char* buffer) {
if (value < 100000000) {
uint32_t v = static_cast<uint32_t>(value);
if (v < 10000) {
const uint32_t d1 = (v / 100) << 1;
const uint32_t d2 = (v % 100) << 1;
if (v >= 1000)
*buffer++ = gDigitsLut[d1];
if (v >= 100)
*buffer++ = gDigitsLut[d1 + 1];
if (v >= 10)
*buffer++ = gDigitsLut[d2];
*buffer++ = gDigitsLut[d2 + 1];
}
else {
// value = bbbbcccc
const uint32_t b = v / 10000;
const uint32_t c = v % 10000;
const uint32_t d1 = (b / 100) << 1;
const uint32_t d2 = (b % 100) << 1;
const uint32_t d3 = (c / 100) << 1;
const uint32_t d4 = (c % 100) << 1;
if (value >= 10000000)
*buffer++ = gDigitsLut[d1];
if (value >= 1000000)
*buffer++ = gDigitsLut[d1 + 1];
if (value >= 100000)
*buffer++ = gDigitsLut[d2];
*buffer++ = gDigitsLut[d2 + 1];
*buffer++ = gDigitsLut[d3];
*buffer++ = gDigitsLut[d3 + 1];
*buffer++ = gDigitsLut[d4];
*buffer++ = gDigitsLut[d4 + 1];
}
}
else if (value < 10000000000000000) {
const uint32_t v0 = static_cast<uint32_t>(value / 100000000);
const uint32_t v1 = static_cast<uint32_t>(value % 100000000);
const uint32_t b0 = v0 / 10000;
const uint32_t c0 = v0 % 10000;
const uint32_t d1 = (b0 / 100) << 1;
const uint32_t d2 = (b0 % 100) << 1;
const uint32_t d3 = (c0 / 100) << 1;
const uint32_t d4 = (c0 % 100) << 1;
const uint32_t b1 = v1 / 10000;
const uint32_t c1 = v1 % 10000;
const uint32_t d5 = (b1 / 100) << 1;
const uint32_t d6 = (b1 % 100) << 1;
const uint32_t d7 = (c1 / 100) << 1;
const uint32_t d8 = (c1 % 100) << 1;
if (value >= 1000000000000000)
*buffer++ = gDigitsLut[d1];
if (value >= 100000000000000)
*buffer++ = gDigitsLut[d1 + 1];
if (value >= 10000000000000)
*buffer++ = gDigitsLut[d2];
if (value >= 1000000000000)
*buffer++ = gDigitsLut[d2 + 1];
if (value >= 100000000000)
*buffer++ = gDigitsLut[d3];
if (value >= 10000000000)
*buffer++ = gDigitsLut[d3 + 1];
if (value >= 1000000000)
*buffer++ = gDigitsLut[d4];
if (value >= 100000000)
*buffer++ = gDigitsLut[d4 + 1];
*buffer++ = gDigitsLut[d5];
*buffer++ = gDigitsLut[d5 + 1];
*buffer++ = gDigitsLut[d6];
*buffer++ = gDigitsLut[d6 + 1];
*buffer++ = gDigitsLut[d7];
*buffer++ = gDigitsLut[d7 + 1];
*buffer++ = gDigitsLut[d8];
*buffer++ = gDigitsLut[d8 + 1];
}
else {
const uint32_t a = static_cast<uint32_t>(value / 10000000000000000); // 1 to 1844
value %= 10000000000000000;
if (a < 10)
*buffer++ = '0' + static_cast<char>(a);
else if (a < 100) {
const uint32_t i = a << 1;
*buffer++ = gDigitsLut[i];
*buffer++ = gDigitsLut[i + 1];
}
else if (a < 1000) {
*buffer++ = '0' + static_cast<char>(a / 100);
const uint32_t i = (a % 100) << 1;
*buffer++ = gDigitsLut[i];
*buffer++ = gDigitsLut[i + 1];
}
else {
const uint32_t i = (a / 100) << 1;
const uint32_t j = (a % 100) << 1;
*buffer++ = gDigitsLut[i];
*buffer++ = gDigitsLut[i + 1];
*buffer++ = gDigitsLut[j];
*buffer++ = gDigitsLut[j + 1];
}
const uint32_t v0 = static_cast<uint32_t>(value / 100000000);
const uint32_t v1 = static_cast<uint32_t>(value % 100000000);
const uint32_t b0 = v0 / 10000;
const uint32_t c0 = v0 % 10000;
const uint32_t d1 = (b0 / 100) << 1;
const uint32_t d2 = (b0 % 100) << 1;
const uint32_t d3 = (c0 / 100) << 1;
const uint32_t d4 = (c0 % 100) << 1;
const uint32_t b1 = v1 / 10000;
const uint32_t c1 = v1 % 10000;
const uint32_t d5 = (b1 / 100) << 1;
const uint32_t d6 = (b1 % 100) << 1;
const uint32_t d7 = (c1 / 100) << 1;
const uint32_t d8 = (c1 % 100) << 1;
*buffer++ = gDigitsLut[d1];
*buffer++ = gDigitsLut[d1 + 1];
*buffer++ = gDigitsLut[d2];
*buffer++ = gDigitsLut[d2 + 1];
*buffer++ = gDigitsLut[d3];
*buffer++ = gDigitsLut[d3 + 1];
*buffer++ = gDigitsLut[d4];
*buffer++ = gDigitsLut[d4 + 1];
*buffer++ = gDigitsLut[d5];
*buffer++ = gDigitsLut[d5 + 1];
*buffer++ = gDigitsLut[d6];
*buffer++ = gDigitsLut[d6 + 1];
*buffer++ = gDigitsLut[d7];
*buffer++ = gDigitsLut[d7 + 1];
*buffer++ = gDigitsLut[d8];
*buffer++ = gDigitsLut[d8 + 1];
}
*buffer = '\0';
return buffer;
}
void i64toa_branchlut(int64_t value, char* buffer) {
uint64_t u = static_cast<uint64_t>(value);
if (value < 0) {
*buffer++ = '-';
u = ~u + 1;
}
u64toa_branchlut(u, buffer);
}
#pragma GCC diagnostic pop