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`include "pronoc_def.v"

/**************************************
 * Module: router_bypass
 * Date:2021-11-14  
 * Author: alireza     
 *
 * Description: 
 *   This file contains HDL modules that can be added
 *   to NoC router to provide multicasting
 ***************************************/
 




/************************************

     look_ahead_routing

 *************************************/
 
module multicast_routing # (
        parameter NOC_ID=0,
        parameter SW_LOC=0,    
        parameter P=5
)(
        current_r_addr,  //current router  address
        dest_e_addr,  // destination endpoint address           
        destport                
);

        `NOC_CONF       
                
        input   [RAw-1   :   0]  current_r_addr;
        input   [DAw-1   :   0]  dest_e_addr;
        output  [DSTPw-1  :   0] destport;
        
        generate
        /* verilator lint_off WIDTH */  
        if(TOPOLOGY=="MESH") begin: mesh
        /* verilator lint_on WIDTH */   
                multicast_routing_mesh #(
                        .NOC_ID(NOC_ID),
                        .P(P) ,
                        .SW_LOC(SW_LOC)         
                ) routing (
                        .current_r_addr(current_r_addr),  //current router  address
                        .dest_e_addr(dest_e_addr),  // destination endpoint address             
                        .destport(destport)             
                );
        /* verilator lint_off WIDTH */  
        end else if (TOPOLOGY == "FMESH") begin : fmesh 
        /* verilator lint_on WIDTH */
                multicast_routing_fmesh #(
                        .NOC_ID(NOC_ID),
                        .P(P) ,
                        .SW_LOC(SW_LOC)         
                ) routing (
                        .current_r_addr(current_r_addr),  //current router  address
                        .dest_e_addr(dest_e_addr),  // destination endpoint address             
                        .destport(destport)             
                );
        
        end else begin 
                initial begin 
                        $display ("ERROR: Multicast/Broadcast is not yet supported for %s Topology",TOPOLOGY);
                        $finish;
                end
        end
        endgenerate
        
 
 
endmodule

module multicast_routing_mesh   #(
        parameter NOC_ID=0,
        parameter SW_LOC=0,   
        parameter P=5
) (
        current_r_addr,  //current router  address
        dest_e_addr,  // destination endpoint address           
        destport                
);   
    
   `NOC_CONF
        
        input   [RAw-1   :   0]  current_r_addr;
        input   [DAw-1   :   0]  dest_e_addr;
        output  [DSTPw-1  :   0] destport;

    
        localparam
                RXw = log2(NX),   
                RYw = log2(NY),  
                EXw = RXw,
                EYw = RYw;
                
                
        //mask gen. x_plus: all rows larger than current router x address are asserted.
        wire [NX-1 : 0] x_plus,x_minus;
        //mask generation. Only the corresponding bits to destination located in current column are asserted in each mask       
        wire [NE-1 : 0] y_plus,y_min;
        //Only one-bit is asserted for each local_p[i]
        wire [NE-1 : 0] local_p [NL-1 : 0];
        
        wire   [RXw-1   :   0]  current_rx;
        wire   [RYw-1   :   0]  current_ry;                  
                        
        mesh_tori_router_addr_decode #(
                        .TOPOLOGY(TOPOLOGY),
                        .T1(T1),
                        .T2(T2),
                        .T3(T3),
                        .RAw(RAw)
                )
                router_addr_decode
                (
                        .r_addr(current_r_addr),
                        .rx(current_rx),
                        .ry(current_ry),
                        .valid( )
                );
                        
                        
                
                wire [NX-1 : 0] row_has_any_dest;
                wire [NE-1 : 0] dest_mcast_all_endp;                    
                
                mcast_dest_list_decode #(
                        .NOC_ID(NOC_ID)
                ) decode (
                        .dest_e_addr(dest_e_addr),
                        .dest_o(dest_mcast_all_endp),
                        .row_has_any_dest(row_has_any_dest),
                        .is_unicast()
                );
                                
                genvar i,j;
                generate 
                        
                        for(i=0; i< NX; i=i+1) begin : X_
                                assign x_plus[i]  = (current_rx >       i);
                                /* verilator lint_off UNSIGNED */
                                assign x_minus[i] = (current_rx <       i);
                                /* verilator lint_on UNSIGNED */
                        end
                                                                
                        //get all endp addresses located in the same x
                        for(i=0; i< NE; i=i+1) begin : endpoints
                        //Endpoint decoded address
                                                        
                                        localparam                                              
                                                Y_LOC = ((i/NL) / NX ), 
                                                X_LOC = ((i/NL) % NX ), 
                                                LL = (i % NL);
                                        localparam [RYw-1   :   0] YY = Y_LOC [RYw-1   :   0];
                                        localparam [RXw-1   :   0] XX = X_LOC [RXw-1   :   0];
                                        
                                        /* verilator lint_off CMPCONST */
                                        assign y_plus[i]  = (current_rx ==      XX) && (current_ry >  YY);
                                        /* verilator lint_on CMPCONST */
                                                
                                        /* verilator lint_off UNSIGNED */
                                        assign y_min[i]   = (current_rx ==      XX) && (current_ry <  YY);
                                        /* verilator lint_on UNSIGNED */
                                        for(j=0;j<NL;j++)begin : lp
                                                assign local_p[j][i] = (current_rx      ==      XX) && (current_ry == YY) && (LL == j);
                                        end             
                                        
                        end //i 
                                        
                        
                        wire goto_north = |(y_plus  & dest_mcast_all_endp);
                        wire goto_south = |(y_min   & dest_mcast_all_endp);
                        wire goto_east  = |(x_minus & row_has_any_dest);
                        wire goto_west  = |(x_plus  & row_has_any_dest);
                        
                        
                        wire [NL-1 : 0] goto_local;
                        for(i=0; i< NL; i=i+1) begin : endps
                                assign goto_local[i] = |(local_p[i] & dest_mcast_all_endp);// will be synthesized as single bit assign
                        end//for
                        
                        
                        
                        reg [4  :   0] destport_tmp;
                        
                        always @(*) begin 
                                destport_tmp = {5{1'b0}};
                                destport_tmp[LOCAL]=goto_local[LOCAL];                          
                                if     (SW_LOC == SOUTH) destport_tmp [NORTH] = goto_north;
                                else if(SW_LOC == NORTH) destport_tmp [SOUTH] = goto_south;
                                else if(SW_LOC == WEST)begin 
                                        destport_tmp [NORTH] = goto_north;
                                        destport_tmp [SOUTH] = goto_south;
                                        destport_tmp [EAST ] = goto_east;                                       
                                end
                                else if(SW_LOC == EAST) begin 
                                        destport_tmp [NORTH] = goto_north;
                                        destport_tmp [SOUTH] = goto_south;
                                        destport_tmp [WEST ] = goto_west;                                       
                                end
                                else if(SW_LOC == LOCAL || SW_LOC > SOUTH) begin
                                        destport_tmp [NORTH] = goto_north;
                                        destport_tmp [SOUTH] = goto_south;
                                        destport_tmp [EAST]  = goto_east;
                                        destport_tmp [WEST]  = goto_west;
                                end                                                     
                        end
                        
                        localparam MSB_DSTP = (DSTPw-1 < SOUTH)? DSTPw-1: SOUTH;
                                
                        assign destport [MSB_DSTP : 0] =destport_tmp;
                        for(i=1;i<NL;i++) begin :other_local
                                assign destport[MSB_DSTP+i]=goto_local[i];                      
                        end     
        endgenerate
        
endmodule



module multicast_routing_fmesh #(
        parameter NOC_ID=0,
        parameter SW_LOC=0,    
        parameter P=5
) (
        current_r_addr,  //current router  address
        dest_e_addr,  // destination endpoint address           
        destport                
);

        `NOC_CONF
        
        input   [RAw-1   :   0]  current_r_addr;
        input   [DAw-1   :   0]  dest_e_addr;
        output  [DSTPw-1 :   0]  destport;

        localparam Pw = log2(MAX_P_FMESH);
        
        localparam              
                RXw = log2(NX),   
                RYw = log2(NY),  
                EXw = RXw,
                EYw = RYw;
        
        wire   [RXw-1   :   0]  current_rx;
        wire   [RYw-1   :   0]  current_ry;   
        
        
        //mask gen. x_plus: all rows larger than current router x address are asserted.
        wire [NX-1 : 0] x_plus,x_minus;
        //mask generation. Only the corresponding bits to destination located in current column are asserted in each mask       
        wire [NE-1 : 0] y_plus,y_min;
        //Only one-bit is asserted for each local_p[i]
        wire [NE-1 : 0] local_p [MAX_P_FMESH-1 : 0];
                        
        mesh_tori_router_addr_decode #(
                .TOPOLOGY(TOPOLOGY),
                .T1(T1),
                .T2(T2),
                .T3(T3),
                .RAw(RAw)
        )
        router_addr_decode
        (
                .r_addr(current_r_addr),
                .rx(current_rx),
                .ry(current_ry),
                .valid( )
        );
        
        
        wire [NX-1 : 0] row_has_any_dest;
        wire [NE-1 : 0] dest_mcast_all_endp;                    
                
        mcast_dest_list_decode # (
                .NOC_ID(NOC_ID)
        ) decode (
                .dest_e_addr(dest_e_addr),
                .dest_o(dest_mcast_all_endp),
                .row_has_any_dest(row_has_any_dest),
                .is_unicast()
        );
        
        
        genvar i,j;
        generate 
                        
        for(i=0; i< NX; i=i+1) begin : X_
                assign x_plus[i]  = (current_rx >       i);
                /* verilator lint_off UNSIGNED */
                assign x_minus[i] = (current_rx <       i);
                /* verilator lint_on UNSIGNED */
        end
                                                                
        //get all endp addresses located in the same x
        for(i=0; i< NE; i=i+1) begin : endpoints
                //Endpoint decoded address
                localparam 
                        ADR = fmesh_addrencode(i),                      
                        XX = ADR [NXw -1 : 0],
                        YY = ADR [NXw+NYw-1 : NXw], 
                        PP = ADR [NXw+NYw+Pw-1 : NXw+NYw];                      
                
                /* verilator lint_off CMPCONST */
                assign y_plus[i]  = (current_rx ==      XX) && (current_ry >  YY);
                /* verilator lint_on CMPCONST */
                                        
                /* verilator lint_off UNSIGNED */
                assign y_min[i]   = (current_rx ==      XX) && (current_ry <  YY);
                /* verilator lint_on UNSIGNED */
                
                for(j=0;j<MAX_P_FMESH;j++)begin : lp
                        assign local_p[j][i] = (current_rx      ==      XX) && (current_ry == YY) && (PP == j);
                end             
        end//for ne
        
        wire [MAX_P_FMESH-1 : 0] goto_local;
        for(i=0; i<MAX_P_FMESH ; i=i+1) begin : endps
                assign goto_local[i] = |(local_p[i] & dest_mcast_all_endp);// will be synthesized as single bit assign
        end//for        
                
                
        wire goto_north = (|(y_plus  & dest_mcast_all_endp)) | goto_local[NORTH];
        wire goto_south = (|(y_min   & dest_mcast_all_endp)) | goto_local[SOUTH];
        wire goto_east  = (|(x_minus & row_has_any_dest))    | goto_local[EAST];
        wire goto_west  = (|(x_plus  & row_has_any_dest))    | goto_local[WEST];
                
                        
        reg [4  :   0] destport_tmp;
                        
        always @(*) begin 
                destport_tmp = {DSTPw{1'b0}};
                destport_tmp[LOCAL]=goto_local[LOCAL];                          
                if     (SW_LOC == SOUTH)begin 
                        destport_tmp [NORTH] = goto_north ;
                        destport_tmp [EAST]  = goto_east;
                        destport_tmp [WEST]  = goto_west;
                end
                else if(SW_LOC == NORTH) begin 
                        destport_tmp [SOUTH] = goto_south ;
                        destport_tmp [EAST]  = goto_east;
                        destport_tmp [WEST]  = goto_west;
                end
                else if(SW_LOC == WEST)begin 
                        destport_tmp [NORTH] = goto_north ;
                        destport_tmp [SOUTH] = goto_south;
                        destport_tmp [EAST ] = goto_east;                                       
                end
                else if(SW_LOC == EAST) begin 
                        destport_tmp [NORTH] = goto_north;
                        destport_tmp [SOUTH] = goto_south;
                        destport_tmp [WEST ] = goto_west;                                       
                end
                else if(SW_LOC == LOCAL || SW_LOC > SOUTH) begin
                        destport_tmp [NORTH] = goto_north;
                        destport_tmp [SOUTH] = goto_south;
                        destport_tmp [EAST]  = goto_east;
                        destport_tmp [WEST]  = goto_west;
                end                                                     
        end
                        
        localparam MSB_DSTP = (DSTPw-1 < SOUTH)? DSTPw-1: SOUTH;
                        
        assign destport [MSB_DSTP : 0] =destport_tmp;
        for(i=1;i<NL;i++) begin :other_local
                assign destport[MSB_DSTP+i]=goto_local[i];                      
        end             
                
                
        endgenerate     
                
endmodule


module mcast_dest_list_decode #(
        parameter NOC_ID=0
) (
        dest_e_addr,
        dest_o,
        row_has_any_dest,
        is_unicast
);
        
        `NOC_CONF
        
        input  [DAw-1 :0]  dest_e_addr;
        output [NE-1 : 0]  dest_o;
        output [NX-1 : 0] row_has_any_dest;
        output is_unicast;
        
        wire   [MCASTw-1 : 0] mcast_dst_coded;
        
        
        
        assign {row_has_any_dest,mcast_dst_coded}=dest_e_addr;
                
        
        
        genvar i;
        generate
        /* verilator lint_off WIDTH */  
        if(CAST_TYPE == "MULTICAST_FULL") begin : full
        /* verilator lint_on WIDTH */ 
                assign dest_o = mcast_dst_coded;
                assign is_unicast = 1'b0;
        /* verilator lint_off WIDTH */  
        end else if (CAST_TYPE == "MULTICAST_PARTIAL") begin : partial
        /* verilator lint_on WIDTH */ 
                wire not_in_cast_list ;
                wire [EAw-1 : 0] unicast_code;
                assign {unicast_code,not_in_cast_list} = mcast_dst_coded  [EAw : 0];
                wire [NE-1 : 0]  dest_o_multi;
                reg  [NE-1 : 0]  dest_o_uni;
                wire [NEw-1 : 0] unicast_id;
                assign is_unicast = not_in_cast_list;
                
                endp_addr_decoder  #(
                        .TOPOLOGY (TOPOLOGY),
                        .T1(T1),
                        .T2(T2),
                        .T3(T3),
                        .EAw(EAw),
                        .NE(NE)
                        )
                        decoder
                        (
                                .code(unicast_code),
                                .id(unicast_id)                         
                        );              
                
                always @(*)begin 
                        dest_o_uni = {NE{1'b0}};
                        dest_o_uni[unicast_id]=1'b1;
                end
                
                for(i=0; i< NE; i=i+1) begin : endpoints
                        localparam MCAST_ID = endp_id_to_mcast_id(i);
                        assign dest_o_multi [i] = (MCAST_ENDP_LIST[i]==1'b1)? mcast_dst_coded[MCAST_ID+1] : 1'b0;                               
                end
                
                assign dest_o = (not_in_cast_list)? dest_o_uni : dest_o_multi;
        /* verilator lint_off WIDTH */  
        end else if (CAST_TYPE == "BROADCAST_FULL") begin : bcast_full
        /* verilator lint_on WIDTH */ 
                wire not_broad_casted;
                wire [EAw-1 : 0] unicast_code;
                assign {unicast_code,not_broad_casted} = mcast_dst_coded;
                assign is_unicast =not_broad_casted;
                wire [NE-1 : 0]  dest_o_multi;
                reg  [NE-1 : 0]  dest_o_uni;
                wire [NEw-1 : 0] unicast_id;            
                
                endp_addr_decoder  #(
                                .TOPOLOGY (TOPOLOGY),
                                .T1(T1),
                                .T2(T2),
                                .T3(T3),
                                .EAw(EAw),
                                .NE(NE)
                        )
                        decoder
                        (
                                .code(unicast_code),
                                .id(unicast_id)                         
                        );              
                
                always @(*)begin 
                        dest_o_uni = {NE{1'b0}};
                        dest_o_uni[unicast_id]=1'b1;
                end
                
                assign dest_o = (not_broad_casted)? dest_o_uni : {NE{1'b1}};
                
        end else begin //BCAST_PARTIAL
                wire not_broad_casted;
                wire [EAw-1 : 0] unicast_code;
                assign {unicast_code,not_broad_casted} = mcast_dst_coded;
                assign is_unicast =not_broad_casted;
                wire [NE-1 : 0]  dest_o_multi;
                reg  [NE-1 : 0]  dest_o_uni;
                wire [NEw-1 : 0] unicast_id;
                
                endp_addr_decoder  #(
                                .TOPOLOGY (TOPOLOGY),
                                .T1(T1),
                                .T2(T2),
                                .T3(T3),
                                .EAw(EAw),
                                .NE(NE)
                        )
                        decoder
                        (
                                .code(unicast_code),
                                .id(unicast_id)                         
                        );              
                
                always @(*)begin 
                        dest_o_uni = {NE{1'b0}};
                        dest_o_uni[unicast_id]=1'b1;
                end
                                
                assign dest_o = (not_broad_casted)? dest_o_uni : MCAST_ENDP_LIST;
                
                
                
        end
                
        endgenerate             
        
endmodule




module multicast_chan_in_process #(
        parameter NOC_ID=0,
        parameter SW_LOC=0,    
        parameter P=5
) (
        endp_port,
        current_r_addr,
        chan_in,
        chan_out,
        clk
);  

        `NOC_CONF
        
        input endp_port;
        input   [RAw-1   :   0]  current_r_addr;
        input   flit_chanel_t chan_in;
        input   clk;
        output  flit_chanel_t chan_out;
        
        
        wire  [MCASTw-1   :   0]  mcast_dst_coded;
        wire  [NE-1 : 0] dest_mcast_all_endp;
        wire [NX-1 : 0] row_has_any_dest,row_has_any_dest_in;   
        wire  [DSTPw-1  :   0] destport,destport_o;     
        
        hdr_flit_t hdr_flit;
        
        header_flit_info #(
                .NOC_ID (NOC_ID)
        ) extract (
                .flit(chan_in.flit),
                .hdr_flit(hdr_flit),            
                .data_o()
        );
        
        mcast_dest_list_decode #(
                .NOC_ID(NOC_ID)
        ) decoder (
                .dest_e_addr(hdr_flit.dest_e_addr),
                .dest_o(dest_mcast_all_endp),
                .row_has_any_dest(row_has_any_dest_in),
                .is_unicast()
        );
        
        localparam MCASTw_= (MCASTw < DAw ) ? MCASTw : DAw;
                
        assign mcast_dst_coded = hdr_flit.dest_e_addr[MCASTw_-1:0];     
        
        genvar i;
        generate 
        if(TOPOLOGY == "MESH") begin : mesh_
                if(SW_LOC == LOCAL || SW_LOC > SOUTH) begin :endp
                                
                        wire [NE/NX-1   :   0] endp_mask [NX-1 : 0];            
                        for(i=0; i< NE; i=i+1) begin : endpoints
                                //Endpoint decoded address                              
                                localparam 
                                        MCAST_ID = endp_id_to_mcast_id(i),
                                        YY = ((i/NL) / NX ), 
                                        XX = ((i/NL) % NX ), 
                                        LL = (i % NL),
                                        PP = YY*NL + LL;
                                assign endp_mask [XX] [PP] = dest_mcast_all_endp [i];                   
                        end
                                
                        for(i=0;i<NX; i++) begin : X_
                                assign row_has_any_dest[i] =| endp_mask[i];                     
                        end     
                        
                        reg   [DSTPw-1  :   0] destport_tmp;
                        always @(*) begin 
                                destport_tmp = destport;
                                if(SELF_LOOP_EN   == "NO") destport_tmp [ SW_LOC ] = 1'b0; 
                        end
                        assign destport_o = destport_tmp;
                        
                end else begin : no_endp
                        assign  row_has_any_dest =       row_has_any_dest_in;
                        assign  destport_o = destport;
                end
        end //mesh      
        
        /* verilator lint_off WIDTH */ 
        else if (TOPOLOGY == "FMESH" ) begin :fmesh_
        /* verilator lint_on WIDTH */ 
                
                
                
                localparam MAX_ENDP_NUM_IN_SAME_ROW = NY * NL + NY + 2;
                localparam ENDP_NUM_IN_MIDLE_ROW = NY * NL + 2;
                localparam Pw = log2(MAX_P_FMESH);
                
                wire [NX-1 : 0] row_has_any_dest_endp_port;     
                wire [NY*NL-1   :   0] endp_mask [NX-1 : 0];            
                        
                for(i=0; i< NE; i=i+1) begin : endpoints
                        //Endpoint decoded address                              
                        localparam 
                                ADR = fmesh_addrencode(i),                                      
                                XX = ADR [NXw -1 : 0],
                                YY = ADR [NXw+NYw-1 : NXw], 
                                PP = ADR [NXw+NYw+Pw-1 : NXw+NYw]; 
                                if(PP == LOCAL || PP > SOUTH) begin 
                                        localparam MM = (PP==LOCAL) ? YY*NL : (YY*NL) + PP - SOUTH;
                                        assign endp_mask [XX] [MM] = dest_mcast_all_endp [i];
                                end
                end
                        
                wire [NX-1 : 0] north_endps;
                wire [NY-1 : 0] west_endps;
                wire [NX-1 : 0] south_endps;
                wire [NY-1 : 0] east_endps;
                
                assign {    east_endps,    west_endps ,south_endps ,north_endps}  = dest_mcast_all_endp [NE-1 :   NY*NL*NX];
                        
                                
                for(i=0;i<NX; i++) begin : X_
                        if(i==0) assign row_has_any_dest_endp_port[i] =(| endp_mask[i]) | ( |west_endps)  | north_endps[i] | south_endps[i];
                        else if (i==NX-1) assign row_has_any_dest_endp_port[i] =(| endp_mask[i]) | ( |east_endps)  | north_endps[i] | south_endps[i];
                        else assign row_has_any_dest_endp_port[i] =(| endp_mask[i]) |  north_endps[i] | south_endps[i];
                end     
                        
                reg   [DSTPw-1  :   0] destport_tmp;
                always @(*) begin 
                        destport_tmp = destport;
                        if(SELF_LOOP_EN   == "NO") destport_tmp [ SW_LOC ] = 1'b0; 
                end
                        
                
                assign  destport_o = (endp_port) ?    destport :  destport_tmp ;
                assign  row_has_any_dest = (endp_port) ? row_has_any_dest_endp_port : row_has_any_dest_in;
                
                
        end
                
                
                
                
                wire [DAw-1 : 0] dest_e_addr = {row_has_any_dest,mcast_dst_coded};
                
                
                multicast_routing
                #(
                        .NOC_ID(NOC_ID),
                        .P(P) ,
                        .SW_LOC(SW_LOC)         
                )
                routing
                (
                        .current_r_addr(current_r_addr),  //current router  address
                        .dest_e_addr(dest_e_addr),  // destination endpoint address             
                        .destport(destport)             
                );
                
                
                
                
                always @(*) begin 
                        chan_out=chan_in;
                        if(chan_in.flit.hdr_flag == 1'b1) begin
                                chan_out.flit [E_DST_MSB : E_DST_LSB] = dest_e_addr;
                                chan_out.flit [DST_P_MSB : DST_P_LSB] = destport_o;                             
                        end
                end     
        
        
        
        //synthesis translate_off       
        if(DEBUG_EN) begin :debg
                always @(posedge clk) begin 
                        /* verilator lint_off WIDTH */ 
                        if(CAST_TYPE == "MULTICAST_FULL" || CAST_TYPE == "MULTICAST_PARTIAL")
                        /* verilator lint_on WIDTH */ 
                        if(chan_in.flit_wr  == 1'b1 && chan_in.flit.hdr_flag == 1'b1 && mcast_dst_coded == {MCASTw{1'b0}}) begin 
                                $display ("%t: ERROR: A multicast packet is injected to the NoC with zero mcast_dst_coded filed %m ",$time);
                                $finish;
                        end
                        
                        if(chan_in.flit_wr  == 1'b1 && chan_in.flit.hdr_flag == 1'b1 && dest_mcast_all_endp == {NE{1'b0}}) begin 
                                $display ("%t: ERROR: A multicast packet is injected to the NoC without any set destination %m ",$time);
                                $finish;
                        end
                        
                        if(chan_in.flit_wr  == 1'b1 && chan_in.flit.hdr_flag == 1'b1 && destport_o == {DSTPw{1'b0}}) begin 
                                $display ("%t: ERROR: Routing module did not set any destination port for an injected multicast packet %m ",$time);
                                $finish;
                        end
                        
                end
        end//debug
        //synthesis translate_on
                
        endgenerate
endmodule



module multicast_dst_sel # (
        parameter NOC_ID=0
)(
        destport_in,
        destport_out    
);

        `NOC_CONF
        
        input  [DSTPw-1 : 0] destport_in;
        output [DSTPw-1 : 0] destport_out; 


        wire  [DSTPw-1 : 0] arb_in, arb_out;
    
        function integer mesh_tori_pririty_order;
                input integer x;
                begin
                        case(x)
                                0 : mesh_tori_pririty_order = EAST;
                                1 : mesh_tori_pririty_order = WEST;
                                2 : mesh_tori_pririty_order = NORTH;
                                3 : mesh_tori_pririty_order = SOUTH;
                                4 : mesh_tori_pririty_order = LOCAL;    
                                default : mesh_tori_pririty_order =x;
                        endcase
                end
        endfunction // pririty_order
        
        function integer ring_lin_pririty_order;
                input integer x;
                begin
                        case(x)
                                0 : ring_lin_pririty_order = FORWARD;
                                1 : ring_lin_pririty_order = BACKWARD;
                                2 : ring_lin_pririty_order = LOCAL;                             
                                default : ring_lin_pririty_order =x;
                        endcase
                end
        endfunction // pririty_order
        
        
        
        
        
        genvar i;
        generate 
                for (i=0; i<DSTPw;i++) begin : lp
                        localparam PR = 
                                /* verilator lint_off WIDTH */ 
                                (TOPOLOGY == "MESH" || TOPOLOGY == "TORUS" || TOPOLOGY == "FMESH"  )?  mesh_tori_pririty_order(i):
                                (TOPOLOGY == "RING" || TOPOLOGY == "LINE") ? ring_lin_pririty_order(i) : i;
                                /* verilator lint_on WIDTH */                                                           
                        assign arb_in[i] = destport_in[PR];
                        assign destport_out [PR] = arb_out[i];
                end
        endgenerate
      
    
        fixed_priority_arbiter #(
                        .ARBITER_WIDTH     (DSTPw), 
                        .HIGH_PRORITY_BIT  ("LSB")
                ) fixed_priority_arbiter (
                        .request           (arb_in), 
                        .grant             (arb_out), 
                        .any_grant         (   )
                );
    
       
   
    
endmodule