mirror of https://github.com/alibaba/MNN.git
38 lines
898 B
Plaintext
38 lines
898 B
Plaintext
#ifndef MNNCUDAFunction_cuh
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#define MNNCUDAFunction_cuh
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struct DivModFast {
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DivModFast(int d = 1)
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{
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d_ = (d == 0) ? 1 : d;
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for (l_ = 0;; ++l_) {
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if ((1U << l_) >= d_)
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break;
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}
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uint64_t one = 1;
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uint64_t m = ((one << 32) * ((one << l_) - d_)) / d_ + 1;
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m_ = static_cast<uint32_t>(m);
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}
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__device__ __inline__ int div(int idx) const
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{
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uint32_t tm = __umulhi(m_, idx); // get high 32-bit of the product
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return (tm + idx) >> l_;
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}
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__device__ __inline__ int mod(int idx) const
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{
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return idx - d_ * div(idx);
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}
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__device__ __inline__ void divmod(int idx, int &quo, int &rem)
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{
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quo = div(idx);
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rem = idx - quo * d_;
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}
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uint32_t d_; // divisor
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uint32_t l_; // ceil(log2(d_))
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uint32_t m_; // m' in the papaer
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};
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#endif |