// Copyright (2019-2023) Paul Scherrer Institute

#include "hls_jfjoch.h"

void stream_merge(AXI_STREAM &input_0,
              AXI_STREAM &input_1,
              AXI_STREAM &output) {
#pragma HLS INTERFACE ap_ctrl_none port=return
#pragma HLS INTERFACE axis register both port=input_0
#pragma HLS INTERFACE axis register both port=input_1
#pragma HLS INTERFACE axis register both port=output

#pragma HLS PIPELINE II=1 style=flp
    enum state {ARBITRATE, FORWARD};
    static state state = ARBITRATE;
    static ap_uint<1> select_input = 0;

    packet_512_t packet_in;
#pragma HLS RESET variable=state
    switch (state) {
        case ARBITRATE:
            if (input_0.read_nb(packet_in)) {
                select_input = 0;
                if (!packet_in.last)
                    state = FORWARD;
                output.write(packet_in);
            } else if (input_1.read_nb(packet_in)) {
                select_input = 1;
                if (!packet_in.last)
                    state = FORWARD;
                output.write(packet_in);
            }
            break;
        case FORWARD:
            if (select_input == 0) {
                input_0.read(packet_in);
            } else
                input_1.read(packet_in);
            output.write(packet_in);

            if (packet_in.last)
                state = ARBITRATE;
            break;
    }
}