#include <thread>
#include <stdio.h>
#include <memory.h>

// compile with g++ cachetear.cpp -lpthread -O2 -g -o cachetear
// spams without optimization

// 64 byte cache lines, tear should cross the line
//#pragma pack(0)  // for MSVC

struct __attribute__((packed)) CTest
{
    char padding[62];
    unsigned int tear;
};

int main(void)
{
    CTest test;
    memset(&test, 0, sizeof(test));

    const int testVal1 = 0xABABABAB;
    const int testVal2 = 0xCDCDCDCD;

    auto test1 = [&test]()
    {
        while(1)
        {
            test.tear = testVal1;
        }
    };

    auto test2 = [&test]()
    {
        while(1)
        {
            test.tear = testVal2;
        }
    };

    std::thread t1(test1);
    std::thread t2(test2);

    printf("Setting up threads...\n");

    while(1)
    {
        if(!(test.tear == testVal1 || test.tear == testVal2))
        {
            printf("Got torn val: 0x%X\n", test.tear);
        }
    }

}