从技术上讲，你可以这样做：

// True if any of the 8 bytes in the integer is 0
bool anyZeroByte( uint64_t v )
{
    // Compute bitwise OR of 8 bits in each byte
    v |= ( v >> 4 ) & 0x0F0F0F0F0F0F0F0Full;
    v |= ( v >> 2 ) & 0x0303030303030303ull;
    constexpr uint64_t lowMask = 0x0101010101010101ull;
    v |= ( v >> 1 ) & lowMask;
    // Isolate the lowest bit
    v &= lowMask;
    // Now these bits are 0 for zero bytes, 1 for non-zero;
    // Invert that bit
    v ^= lowMask;
    // Now these bits are 1 for zero bytes, 0 for non-zero
    // Compute the result
    return 0 != v;
}

但是SIMD会更快。SSE是x64架构的绝对要求，世界上所有的AMD64处理器都需要支持SSE1和SSE2。下面是SSE2版本：

bool anyZeroByteSse2( uint64_t v )
{
    __m128i vec = _mm_cvtsi64_si128( (int64_t)v );
    __m128i zero = _mm_setzero_si128();
    __m128i eq = _mm_cmpeq_epi8( vec, zero );
    return 0 != ( _mm_movemask_epi8( eq ) & 0xFF );
}

这是6条指令而不是16条：link。