Review the Code Changes - 2023.1 English

Vitis Tutorials: Hardware Acceleration (XD099)

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Release Date
2023.1 English

There are now four arrays for the distances:

uint16_t distances_0[N][N];
uint16_t distances_1[N][N];
uint16_t distances_2[N][N];
uint16_t distances_3[N][N];

The incoming distance data points are still read one at a time, but they are copied into all four memories:

loop_distances: for (int i = 0; i < N*N; ++i)
    uint16_t val;
    streamDistances >> val;
    distances_0[i/N][i%N] = val;
    distances_1[i/N][i%N] = val;
    distances_2[i/N][i%N] = val;
    distances_3[i/N][i%N] = val;

The loop_compute main loop continuously increments by four and distributes the four values to copies of the compute function. Each evaluates a route:

loop_compute: for( unsigned long int i_ = 0; i_ < factorialN; i_ += 4 )
    #pragma HLS pipeline II=1
    candidate0 = std::min(candidate0, compute(i_+0, distances_0));
    candidate1 = std::min(candidate1, compute(i_+1, distances_1));
    candidate2 = std::min(candidate2, compute(i_+2, distances_2));
    candidate3 = std::min(candidate3, compute(i_+3, distances_3));

Final determination of the shortest distance:

    // Determine shortest between the four candidates
    shortestDistance = std::min({ candidate0, candidate1,
                                  candidate2, candidate3 });