将uint64_t的位复制到特定位置的两个uint64_t中

#include <iostream>
#include <cstdint>

void copyBits(uint64_t value, uint64_t& dest1, uint64_t& dest2, int start, int length) {
    uint64_t mask = ((1ULL << length) - 1) << start;
    uint64_t masked_value = value & mask;
    uint64_t copied_value = masked_value >> start;
    dest1 = copied_value;
    dest2 = copied_value;
}

int main() {
    uint64_t value = 0x1234567890ABCDEF;
    uint64_t dest1, dest2;
    int start = 8;
    int length = 16;
    copyBits(value, dest1, dest2, start, length);
    std::cout << "dest1: " << std::hex << dest1 << std::endl;
    std::cout << "dest2: " << std::hex << dest2 << std::endl;
    return 0;
}

dest1: 3456
dest2: 3456