After creatng and filling the buffers with data from the host application, you must then sync the buffer to the Xilinx device to make the data accessible to the device binary (xclbin). The data is transferred from the host computer to the Xilinx device and accelerator card where it is available for the kernel to use, as shown in the code example below:
// Map the contents of the buffer object into host memory
auto bo0_map = ip1_boA.map<int*>();
auto bo1_map = ip1_boB.map<int*>();
std::fill(bo0_map, bo0_map + DATA_SIZE, 0);
std::fill(bo1_map, bo1_map + DATA_SIZE, 0);
// Create the test data
int bufReference[DATA_SIZE];
for (int i = 0; i < DATA_SIZE; ++i) {
bo0_map[i] = i;
bo1_map[i] = i;
bufReference[i] = bo0_map[i] + bo1_map[i]; //Generate check data for validation
}
std::cout << "loaded the data" << std::endl;
uint64_t buf_addr[2];
// Get the buffer physical address
buf_addr[0] = ip1_boA.address();
buf_addr[1] = ip1_boB.address();
// Synchronize buffer content with device side
std::cout << "synchronize input buffer data to device global memory\n";
ip1_boA.sync(XCL_BO_SYNC_BO_TO_DEVICE);
ip1_boB.sync(XCL_BO_SYNC_BO_TO_DEVICE);
In the example code, you can see that the addresses of the buffers are captured in the buf_addr vector. This information will be needed when writing or reading to the registers associated with the kernel arguments.