41 lines
1.1 KiB
Go
41 lines
1.1 KiB
Go
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package dh
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const (
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// QSizeMinimum Specifies the number of the most significant bit (0 to M).
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// WARNING: internally, usually 1 to N.
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QSizeMinimum = 511
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// Prime sieving constants
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// Assuming 8 bit bytes and 32 bit words.
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ShiftBit = 3
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ShiftByte = 2
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ShiftWord = ShiftBit + ShiftByte
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ShiftMegabyte = 20
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ShiftMegaWord = ShiftMegabyte - ShiftBit
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// Memory limits.
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// LargeMinimum is 8 megabytes
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LargeMinimum = uint32(8) // Originally an 8UL in moduli.c
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// LargeMaximum is 127MB.
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LargeMaximum = uint32(127)
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// The largest sieve prime has to be < 2**32 on 32-bit systems.
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SmallMaximum = uint32(0xffffffff) // 4294967295
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// Can sieve all primes less than 2**32, as 65537**2 > 2**32-1.
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TinyNumber = uint32(1) << 16
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// Ensure enough bit space for testing 2*q.
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TestMaximum = uint32(1) << 16
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TestMinimum = QSizeMinimum + 1 // (uint32(1) << (ShiftWord - TestPower))
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TestPower = 3 // 2**n, n < ShiftWord
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)
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var (
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)
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// Bit* functions operate on 32-bit words
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func BitClear(a []uint32, n uint32) (i uint32) {
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i = a[n >> ShiftWord] &= ~(uint32(1) << (n & 31))
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return
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}
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