79 lines
1.8 KiB
C++
79 lines
1.8 KiB
C++
namespace factor {
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inline cell log2(cell x) {
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cell n;
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#if defined(FACTOR_X86)
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#if defined(_MSC_VER)
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_BitScanReverse((unsigned long*)&n, x);
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#else
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asm("bsr %1, %0;" : "=r"(n) : "r"(x));
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#endif
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#elif defined(FACTOR_AMD64)
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#if defined(_MSC_VER)
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n = 0;
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_BitScanReverse64((unsigned long*)&n, x);
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#else
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asm("bsr %1, %0;" : "=r"(n) : "r"(x));
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#endif
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#elif defined(FACTOR_PPC64)
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#if defined(__GNUC__)
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n = (63 - __builtin_clzll(x));
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#else
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#error Unsupported compiler
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#endif
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#elif defined(FACTOR_PPC32)
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#if defined(__GNUC__)
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n = (31 - __builtin_clz(x));
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#else
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#error Unsupported compiler
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#endif
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#else
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#error Unsupported CPU
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#endif
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return n;
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}
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inline cell rightmost_clear_bit(cell x) { return log2(~x & (x + 1)); }
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inline cell rightmost_set_bit(cell x) { return log2(x & (~x + 1)); }
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inline cell popcount(cell x) {
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#if defined(__GNUC__)
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#ifdef FACTOR_64
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return __builtin_popcountll(x);
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#else
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return __builtin_popcount(x);
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#endif
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#else
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#ifdef FACTOR_64
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uint64_t k1 = 0x5555555555555555ll;
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uint64_t k2 = 0x3333333333333333ll;
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uint64_t k4 = 0x0f0f0f0f0f0f0f0fll;
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uint64_t kf = 0x0101010101010101ll;
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cell ks = 56;
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#else
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uint32_t k1 = 0x55555555;
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uint32_t k2 = 0x33333333;
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uint32_t k4 = 0xf0f0f0f;
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uint32_t kf = 0x1010101;
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cell ks = 24;
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#endif
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x = x - ((x >> 1) & k1); // put count of each 2 bits into those 2 bits
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x = (x & k2) + ((x >> 2) & k2); // put count of each 4 bits into those 4 bits
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x = (x + (x >> 4)) & k4; // put count of each 8 bits into those 8 bits
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x = (x * kf) >> ks; // returns 8 most significant bits of x + (x<<8) +
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// (x<<16) + (x<<24) + ...
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return x;
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#endif
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}
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inline bool bitmap_p(uint8_t* bitmap, cell index) {
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cell byte = index >> 3;
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cell bit = index & 7;
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return (bitmap[byte] & (1 << bit)) != 0;
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}
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}
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