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   static const unsigned long long m4 = 0x0f0f0f0f0f0f0f0f; //binary:  4 zeros,  4 ones ...
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   static const unsigned long long m4 = 0x0f0f0f0f0f0f0f0f; //binary:  4 zeros,  4 ones ...
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   static const unsigned long long h01 = 0x0101010101010101; //the sum of 256 to the power of 0,1,2,3...
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   static const unsigned long long h01 = 0x0101010101010101; //the sum of 256 to the power of 0,1,2,3...
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   x -= (x >> 1) & m1;             //put count of each 2 bits into those 2 bits
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   x -= (x >> 1) & m1;             //put count of each 2 bits into those 2 bits
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   x = (x & m2) + ((x >> 2) & m2); //put count of each 4 bits into those 4 bits
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   x = (x & m2) + ((x >> 2) & m2); //put count of each 4 bits into those 4 bits
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   x = (x + (x >> 4)) & m4;        //put count of each 8 bits into those 8 bits
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   x = (x + (x >> 4)) & m4;        //put count of each 8 bits into those 8 bits
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   return static_cast<int>((x * h01) >> 56);  //returns left 8 bits of x + (x<<8) + (x<<16) + (x<<24) + ...
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   return (int)((x * h01) >> 56);  //returns left 8 bits of x + (x<<8) + (x<<16) + (x<<24) + ...
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}
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}
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#endif // Pierre-Marie Baty -- __builtin_popcountll support for MSVC 32-bit
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#endif // Pierre-Marie Baty -- __builtin_popcountll support for MSVC 32-bit
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#ifndef __builtin_ctzll // Pierre-Marie Baty -- __builtin_ctzll support for MSVC 32-bit
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#ifndef __builtin_ctzll // Pierre-Marie Baty -- __builtin_ctzll support for MSVC 32-bit
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#include <intrin.h>
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int __builtin_ctzll (unsigned long long x)
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int __builtin_ctzll (unsigned long long x)
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{
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{
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   // Returns the number of trailing 0-bits in x, starting at the least significant bit position.
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   // Returns the number of trailing 0-bits in x, starting at the least significant bit position.
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   // If x is zero, the result is undefined.
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   // If x is zero, the result is undefined.
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   // This uses a binary search algorithm from Hacker's Delight.
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   // This uses a binary search algorithm from Hacker's Delight.