sse_matrix44_mul_test.cpp

#include <xmmintrin.h>
#include <chrono>
#include <iostream>
#include <iomanip>
using namespace std;
using namespace chrono;

#ifdef _MSC_VER
__declspec(align(16)) struct matrix44
#else
struct alignas(16) matrix44
#endif
{
    float a[4][4];
};

matrix44 std_mul(matrix44 const& m1, matrix44 const& m2)
{
    matrix44 res;
    for (int i = 0; i < 4; ++i)
    {
        for (int j = 0; j < 4; ++j)
        {
            res.a[i][j] = m1.a[i][0] * m2.a[0][j];
            for (int k = 1; k < 4; ++k)
            {
                res.a[i][j] += m1.a[i][k] * m2.a[k][j];
            }
        }
    }
    return res;
}

matrix44 unroll_mul(matrix44 const& m1, matrix44 const& m2)
{
    matrix44 res;
    for (int i = 0; i < 4; ++i)
    {
        for (int j = 0; j < 4; ++j)
        {
            res.a[i][j] = m1.a[i][0] * m2.a[0][j];
            res.a[i][j] += m1.a[i][1] * m2.a[1][j];
            res.a[i][j] += m1.a[i][2] * m2.a[2][j];
            res.a[i][j] += m1.a[i][3] * m2.a[3][j];
        }
    }
    return res;
}

matrix44 sse_mul(matrix44 const& m1, matrix44 const& m2)
{
    matrix44 res;

    __m128 a, b, r;
    for (int i = 0; i < 4; ++i)
    {
        a = _mm_set1_ps(m1.a[i][0]);
        b = _mm_load_ps(m2.a[0]);
        r = _mm_mul_ps(a, b);
        for (int j = 1; j < 4; ++j)
        {
            a = _mm_set1_ps(m1.a[i][j]);
            b = _mm_load_ps(m2.a[j]);
            r = _mm_add_ps(_mm_mul_ps(a, b), r);
        }
        _mm_store_ps(res.a[i], r);
    }

    return res;
}

struct timer
{
    char const* name;
    high_resolution_clock::time_point start;
    timer(char const* p)
        : name{ p }
        , start{ high_resolution_clock::now() }
    {
    }
 
    ~timer()
    {
        auto duration = high_resolution_clock::now() - start;
        cout << setw(10) << name << ": " << duration_cast<nanoseconds>(duration).count() << endl;
    }
};
 
template<typename F>
void time_it(char const* name, F f, int count)
{
    matrix44 res;
    {
        timer t{ name };
        matrix44 a =
        {
            1, 0, 0, 0,
            0, 1, 0, 0,
            0, 0, 1, 0,
            0, 0, 0, 1
        };
        for (int i = 0; i < count; ++i)
        {
            res = f(a, a);
        }
    }
    cout << res.a[0][0] << endl;
}
 
int main()
{
    int const count = 1000000;
    for (int i = 0; i < 3; ++i)
    {
        time_it("std_mul", std_mul, count);
        time_it("unroll_mul", unroll_mul, count);
        time_it("sse_mul", sse_mul, count);
    }
}