crossbar.h

/*
 * Copyright (c) 2017-2019, NVIDIA CORPORATION.  All rights reserved.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License")
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *     http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
#ifndef CROSSBAR_H
#define CROSSBAR_H
 
#include "nvhls_int.h"
#include "nvhls_types.h"
#include <stdio.h>
 
// this section probably deserves it's own h file
// in context of crossbar this function is used to zero out bits for any data
// type in case the output is invalid. We do not want to deal with Xes.
template <class T>
T zero_bits() {
    T t;
    t = (T){0};
    return t;
}
 
template <typename DataType, unsigned NumInputLanes, unsigned NumOutputLanes>
void crossbar(DataType data_in[NumInputLanes], bool valid_in[NumInputLanes],
        NVUINTW(nvhls::index_width<NumInputLanes >::val) source[NumOutputLanes],
        bool valid_source[NumOutputLanes],
        DataType data_out[NumOutputLanes],
        bool valid_out[NumOutputLanes]) {
 
    NVUINTW(nvhls::index_width<NumInputLanes>::val) source_tmp;
    bool valid_in_tmp;
    DataType data_in_tmp;
 
#pragma hls_unroll yes
    for (unsigned dst = 0; dst < NumOutputLanes; dst++) {
        source_tmp = source[dst];
        if (!valid_source[dst]) {
            source_tmp = 0;
        }
        valid_in_tmp = valid_in[source_tmp];
        data_in_tmp = data_in[source_tmp];
 
        if (valid_source[dst] && valid_in_tmp) {
            data_out[dst] = data_in_tmp;
            valid_out[dst] = true;
        } else {
            data_out[dst] = zero_bits<DataType>();
            valid_out[dst] = false;
        }
    }
}
 
template <typename DataType, unsigned NumInputLanes, unsigned NumOutputLanes>
void crossbar(DataType data_in[NumInputLanes], bool valid_in[NumInputLanes],
        NVUINTW(nvhls::index_width<NumInputLanes>::val) source[NumOutputLanes],
        DataType data_out[NumOutputLanes],
        bool valid_out[NumOutputLanes]) {
 
    bool valid_source[NumOutputLanes];
    for (unsigned i = 0; i < NumOutputLanes; ++i)
        valid_source[i] = true;
 
    crossbar<DataType, NumInputLanes, NumOutputLanes>(
            data_in, valid_in, source, valid_source, data_out, valid_out);
}
 
template <typename DataType, unsigned NumInputLanes, unsigned NumOutputLanes>
void crossbar(DataType data_in[NumInputLanes],
        NVUINTW(nvhls::index_width<NumInputLanes>::val) source[NumOutputLanes],
        DataType data_out[NumOutputLanes]) {
 
    bool valid_out[NumOutputLanes];
    bool valid_in[NumInputLanes];
    for (unsigned int i = 0; i < NumInputLanes; ++i)
        valid_in[i] = true;
 
    crossbar<DataType, NumInputLanes, NumOutputLanes>(data_in, valid_in, source,
            data_out, valid_out);
}
 
#endif  // CROSSBAR_H