// 32-bit transpose, loading/storing a 4x4 tile of elements
// Only used for activations
// converts to FP16
// also adds zero padding for non multiple of 8 prompt lengths
#pragma OPENCL EXTENSION cl_khr_fp16 : enable

kernel void kernel_transpose_32_16(__read_only image1d_buffer_t input, __write_only image1d_buffer_t output, const uint rows, const uint cols, const uint padded_rows) {

    const int i = get_global_id(0);
    const int j = get_global_id(1);
    const int i_2 = i<<2;
    const int j_2 = j<<2;
    half4 temp0 = {0,0,0,0}; // initialize outputs to 0
    half4 temp1 = {0,0,0,0};
    half4 temp2 = {0,0,0,0};
    half4 temp3 = {0,0,0,0};

    if((j_2+0)*cols+i*4+3 < rows*cols*16){ // only load from a valid location. Otherwise keep register data as 0
        temp0 = read_imageh(input, (j_2+0)*cols+i);
    }
    if((j_2+1)*cols+i*4+3 < rows*cols*16){
        temp1 = read_imageh(input, (j_2+1)*cols+i);
    }
    if((j_2+2)*cols+i*4+3 < rows*cols*16){
        temp2 = read_imageh(input, (j_2+2)*cols+i);
    }
    if((j_2+3)*cols+i*4+3 < rows*cols*16){
        temp3 = read_imageh(input, (j_2+3)*cols+i);
    }

    write_imageh(output, (i_2+0)*padded_rows+j, (half4)(temp0.s0, temp1.s0, temp2.s0, temp3.s0)); // no conditionals for output, includes zero padding
    write_imageh(output, (i_2+1)*padded_rows+j, (half4)(temp0.s1, temp1.s1, temp2.s1, temp3.s1));
    write_imageh(output, (i_2+2)*padded_rows+j, (half4)(temp0.s2, temp1.s2, temp2.s2, temp3.s2));
    write_imageh(output, (i_2+3)*padded_rows+j, (half4)(temp0.s3, temp1.s3, temp2.s3, temp3.s3));
}