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module gfx_fifo
#(int WIDTH = 0,
int DEPTH = 0)
(
input logic clk,
rst_n,
gfx_beats.rx in,
gfx_beats.tx out
);
logic do_read, do_write, full_if_eq, in_stall, out_stall,
may_read, may_write, read, read_ok, write;
logic[WIDTH - 1:0] fifo[DEPTH], read_data, write_data;
logic[$clog2(DEPTH) - 1:0] read_ptr, write_ptr;
assign do_read = read & may_read;
assign do_write = write & may_write;
always_comb begin
may_read = full_if_eq;
may_write = !full_if_eq;
if (read)
may_write = 1;
if (read_ptr != write_ptr) begin
may_read = 1;
may_write = 1;
end
end
gfx_skid_flow in_flow
(
.clk,
.rst_n,
.stall(in_stall),
.in_ready(in.ready),
.in_valid(in.valid),
.out_ready(may_write),
.out_valid(write)
);
gfx_skid_flow out_flow
(
.clk,
.rst_n,
.stall(out_stall),
.in_ready(read),
.in_valid(read_ok),
.out_ready(out.ready),
.out_valid(out.valid)
);
gfx_skid_buf #(WIDTH) in_skid
(
.clk,
.in(in.data),
.out(write_data),
.stall(in_stall)
);
gfx_skid_buf #(WIDTH) out_skid
(
.clk,
.in(read_data),
.out(out.data),
.stall(out_stall)
);
always_ff @(posedge clk or negedge rst_n)
if (~rst_n) begin
read_ok <= 0;
read_ptr <= 0;
write_ptr <= 0;
full_if_eq <= 0;
end else begin
if (~out_stall)
read_ok <= read && may_read;
if (do_read)
read_ptr <= read_ptr + 1;
if (do_write)
write_ptr <= write_ptr + 1;
if (do_read & ~do_write)
full_if_eq <= 0;
else if (~do_read & do_write)
full_if_eq <= 1;
end
always_ff @(posedge clk) begin
if (~out_stall)
read_data <= fifo[read_ptr];
if (may_write)
fifo[write_ptr] <= write_data;
end
endmodule
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