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module mac_rxfifo_int
(input clk, input rst,
input Rx_mac_empty,
output Rx_mac_rd,
input [31:0] Rx_mac_data,
input [1:0] Rx_mac_BE,
input Rx_mac_sop,
input Rx_mac_eop,
input Rx_mac_err,
output [31:0] wr_dat_o,
output wr_write_o,
output wr_done_o,
output wr_error_o,
input wr_ready_i,
input wr_full_i,
// FIFO Status
output [15:0] fifo_occupied,
output fifo_full,
output fifo_empty
);
// Write side of short FIFO
// Inputs: full, Rx_mac_empty, Rx_mac_sop, Rx_mac_eop, Rx_mac_err, Rx_mac_data/BE
// Controls: write, datain, Rx_mac_rd
wire write, full, read, empty, sop_o, eop_o, error_o;
// Write side of short FIFO
assign write = ~full & ~Rx_mac_empty;
assign Rx_mac_rd = write;
`define LONGFIFO 0
`ifdef LONGFIFO
cascadefifo2 #(.WIDTH(35),.SIZE(10)) mac_rx_longfifo
(.clk(clk),.rst(rst),.clear(0),
.datain({Rx_mac_sop,Rx_mac_eop,Rx_mac_err,Rx_mac_data}),.write(write),.full(full),
.dataout({sop_o,eop_o,error_o,wr_dat_o}),.read(read),.empty(empty),
.space(), .occupied(fifo_occupied) );
`else
shortfifo #(.WIDTH(35)) mac_rx_sfifo
(.clk(clk),.rst(rst),.clear(0),
.datain({Rx_mac_sop,Rx_mac_eop,Rx_mac_err,Rx_mac_data}),.write(write),.full(full),
.dataout({sop_o,eop_o,error_o,wr_dat_o}),.read(read),.empty(empty),
.space(), .occupied(fifo_occupied[4:0]) );
assign fifo_occupied[15:5] = 0;
`endif
assign fifo_full = full;
assign fifo_empty = empty;
// Read side of short FIFO
// Inputs: empty, dataout, wr_ready_i, wr_full_i
// Controls: read, wr_dat_o, wr_write_o, wr_done_o, wr_error_o
reg [1:0] rd_state;
localparam RD_IDLE = 0;
localparam RD_HAVEPKT = 1;
localparam RD_XFER = 2;
localparam RD_ERROR = 3;
always @(posedge clk)
if(rst)
rd_state <= RD_IDLE;
else
case(rd_state)
RD_IDLE :
if(sop_o & ~empty)
rd_state <= RD_HAVEPKT;
RD_HAVEPKT :
if(wr_ready_i)
rd_state <= RD_XFER;
RD_XFER :
if(eop_o & ~empty)
rd_state <= RD_IDLE;
else if(wr_full_i)
rd_state <= RD_HAVEPKT;
RD_ERROR :
rd_state <= RD_IDLE;
endcase // case(rd_state)
assign read = ~empty & ((rd_state == RD_XFER) | ((rd_state==RD_IDLE)&~sop_o));
assign wr_write_o = ~empty & (rd_state == RD_XFER);
assign wr_done_o = ~empty & (rd_state == RD_XFER) & eop_o;
assign wr_error_o = ~empty & (rd_state == RD_XFER) & error_o;
endmodule // mac_rxfifo_int
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