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22 lines
485 B
C++
22 lines
485 B
C++
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#pragma once
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namespace nall {
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struct BarrettReduction {
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BarrettReduction(uint256_t modulo) : modulo(modulo), factor((1_u1024 << 512) / modulo) {}
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//return = value % modulo
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inline auto operator()(uint512_t value) const -> uint256_t {
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uint512_t hi, lo;
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nall::mul(value, factor, hi, lo);
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uint512_t remainder = value - hi * modulo;
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return remainder < modulo ? remainder : remainder - modulo;
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}
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private:
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const uint512_t modulo;
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const uint512_t factor;
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};
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}
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