gistfile1.cpp

#include <iostream>
#include <assert.h>
#include <math.h>

__global__ void f(float sum, int B, float *z, float *z2)
{
    *z = sum / B;
    *z2 = sum / (float)B;
}

int main(int argc, char *argv[])
{
    float a = 3 + argc;
    int b = 2 + argc;

    std::cerr << a << " / " << b << " = " << std::endl;

    float z;
    float *dev_ptr_z;
    cudaMalloc(&dev_ptr_z, sizeof(*dev_ptr_z));

    float z2;
    float *dev_ptr_z2;
    cudaMalloc(&dev_ptr_z2, sizeof(*dev_ptr_z2));

    f<<<1,1>>>(a, b, dev_ptr_z, dev_ptr_z2);

    cudaDeviceSynchronize();

    cudaMemcpy(&z, dev_ptr_z, sizeof(z), cudaMemcpyDeviceToHost);
    cudaMemcpy(&z2, dev_ptr_z2, sizeof(z2), cudaMemcpyDeviceToHost);

    cudaFree(dev_ptr_z);
    cudaFree(dev_ptr_z2);

    std::cerr << "z = " << z << " " << std::hex << (*(int*)&z) << std::dec << std::endl;
    std::cerr << "z2 = " << z2 << " " << std::hex << (*(int*)&z2) << std::dec << std::endl;

    assert(z == z2);

    return 0;
}