问题

索博尔算法中用到了_BitScanForward这个函数，在做统信UOS适配的时候发现这个函数是MSVC专有的，百度了一下linux下对应的有__builtin_ctz相关的系列函数

头文件引用

代码对比

win

#include <iostream>
#include <intrin.h>
using namespace std;

#pragma intrinsic(_BitScanForward)

static const unsigned QRNG_NDMS = 32;
    struct
    {
        unsigned __int64 uValue;
        unsigned uPrevSeed;
    } m_prev[QRNG_NDMS];

unsigned __int64 cjn[QRNG_NDMS][63] = { 0 };

int main()
{
    unsigned long mask = 0;
    unsigned long index;
    unsigned char isNonzero;

    unsigned m_uCurSeed = 2048,m_uCurDim;
    m_uCurDim = 0;
    unsigned grayCode = (m_uCurSeed >> 1) ^ m_uCurSeed;
    unsigned changedBits = m_prev[m_uCurDim].uPrevSeed ^ grayCode;
    unsigned long uBit;
    
    while (_BitScanForward(&uBit, changedBits))
    {
        cout << uBit << endl << changedBits <<endl;
        m_prev[m_uCurDim].uValue ^= cjn[m_uCurDim][uBit];
        changedBits &= ~(1 << uBit);
    }
    
    cout << uBit << endl << changedBits <<endl;

    return 0;
}
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Linux

#include <iostream>
#include <x86intrin.h>

using namespace std;

static const unsigned QRNG_NDMS = 32;
    struct
    {
        unsigned long long uValue;
        unsigned uPrevSeed;
    } m_prev[QRNG_NDMS];

unsigned long long cjn[QRNG_NDMS][63] = { 0 };

int main(int, char**) {
    unsigned long mask = 0;
    unsigned long index = 0;
    unsigned char isNonzero;

    unsigned m_uCurSeed = 2048,m_uCurDim;
    m_uCurDim = 0;
    unsigned grayCode = (m_uCurSeed >> 1) ^ m_uCurSeed;
    unsigned changedBits = m_prev[m_uCurDim].uPrevSeed ^ grayCode;
    unsigned long uBit;
    cout << __builtin_ctzl(10) << endl;
    while (true)
    {
        uBit = __builtin_ctzl(changedBits);
        if(uBit >= 64){
            break;
        }
        cout << uBit << endl << changedBits <<endl;
        m_prev[m_uCurDim].uValue ^= cjn[m_uCurDim][uBit];
        changedBits &= ~(1 << uBit);
    }
    
    cout << uBit << endl << changedBits <<endl;
}

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