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module gfx_fifo
#(parameter WIDTH=0, DEPTH=0)
(
input logic clk,
rst_n,
input logic[WIDTH - 1:0] in,
input logic in_valid,
output logic in_ready,
input logic out_ready,
output logic out_valid,
output logic[WIDTH - 1:0] 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
(
.stall(in_stall),
.out_ready(may_write),
.out_valid(write),
.*
);
gfx_skid_flow out_flow
(
.stall(out_stall),
.in_ready(read),
.in_valid(read_ok),
.*
);
gfx_skid_buf #(.WIDTH(WIDTH)) in_skid
(
.out(write_data),
.stall(in_stall),
.*
);
gfx_skid_buf #(.WIDTH(WIDTH)) out_skid
(
.in(read_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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