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more branchless mormord - slower

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This commit is contained in:
Richard Thier 2024-04-11 19:53:58 +02:00
parent 2d2cad2c5a
commit f4ceffe6e2
1 changed files with 5 additions and 7 deletions
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ypsu.cpp
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@ -185,18 +185,16 @@ static inline void mormord_sort_impl(uint32_t *a, int n) noexcept {
/* (because radix value 3 is not found in input) */ /* (because radix value 3 is not found in input) */
uint32_t prev = 0; uint32_t prev = 0;
uint32_t reali = 0; uint32_t reali = 0;
#pragma GCC unroll 16 #pragma GCC unroll 256
for(int i = 0; i < 256; ++i) { for(int i = 0; i < 256; ++i) {
radics[i] += prev; radics[i] += prev;
if(radics[i] != 0) { bool act =(radics[i] != 0);
real_radics[reali] = prev; real_radics[reali] = act ? prev : real_radics[reali];
real_radics[reali + 1] = radics[i]; real_radics[reali + 1] = act ? radics[i] : real_radics[reali + 1];
reali += 2; reali += 2 * act;
}
prev = radics[i]; prev = radics[i];
} }
// Inplace swap - own ideas + some ideas based-on "famous" ct-swap (for branchless / more ILP): // Inplace swap - own ideas + some ideas based-on "famous" ct-swap (for branchless / more ILP):
// void ct-swap(bool secret, uint64_t a[], uint64_t b[], size_t len) { // void ct-swap(bool secret, uint64_t a[], uint64_t b[], size_t len) {
// uint64_t mask = ~((uint64_t)secret - 1); // 1->111....111; 0->000....000 // uint64_t mask = ~((uint64_t)secret - 1); // 1->111....111; 0->000....000