#define TS  32
#define WPT  8
#define RTS (TS/WPT)

// super super slow sgemm kernel by heehoon
__kernel void sgemm(__global float *A, __global float *B, __global float *C, int M, int N, int K) {

// Thread identifiers
    const int row = get_local_id(0); // Local row ID (max: TS)
    const int col = get_local_id(1); // Local col ID (max: TS/WPT == RTS)
    const int globalRow = TS*get_group_id(0) + row; // Row ID of C (0..M)
    const int globalCol = TS*get_group_id(1) + col; // Col ID of C (0..N)
 
    // Local memory to fit a tile of TS*TS elements of A and B
    __local float Asub[TS][TS];
    __local float Bsub[TS][TS];
 
    // Initialise the accumulation registers
    float acc[WPT];
    for (int w=0; w<WPT; w++) {
        acc[w] = 0.0f;
    }
    
    // Loop over all tiles
    const int numTiles = K/TS;
    //const int numTiles = (K+TS-1)/TS;
    for (int t=0; t<numTiles+1 ; t++) {
 
        // Load one tile of A and B into local memory
            for (int w=0; w<WPT; w++) {
                const int tiledRow = TS*t + row;
                const int tiledCol = TS*t + col;
		//if(row+w*RTS>=32) printf("That is out!");
		//if(col>=32) printf("That is out!");
	
	        if(((globalRow + w*RTS) >= M) || (tiledCol >= K)){
		    Asub[row + w*RTS][col] = 0.0f;
		}
		else{
		    Asub[row + w*RTS][col] = A[(globalRow + w*RTS)*K + tiledCol];
		}
		if(((tiledRow + w*RTS) >= K) || (globalCol >= N)){
		    Bsub[row + w*RTS][col] = 0.0f;
		}
		else{
                    Bsub[row + w*RTS][col] = B[(tiledRow + w*RTS)*N + globalCol];
		}
            }
	 
        // Synchronise to make sure the tile is loaded
        barrier(CLK_LOCAL_MEM_FENCE);
 
        // Perform the computation for a single tile
        for (int k=0; k<TS; k++) {
            for (int w=0; w<WPT; w++) {
                acc[w] += Asub[row + w*RTS][k] * Bsub[k][col];
            }
        }
 
        // Synchronise before loading the next tile
        barrier(CLK_LOCAL_MEM_FENCE);
    }
 
    // Store the final results in C
    for (int w=0; w<WPT; w++) {
	if(((globalRow + w*RTS) <M) && (globalCol < N)){
            C[(globalRow + w*RTS)*N + globalCol] = acc[w];
	}
    }

}