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|
module gfx_bootrom
import gfx::*;
(
input logic clk,
rst_n,
if_axil.s axis
);
localparam ROM_WORDS_LOG = 7;
enum int unsigned
{
WAIT,
READ,
RDATA,
READY
} state;
word read, rom[1 << ROM_WORDS_LOG];
logic[ROM_WORDS_LOG - 1:0] read_addr;
assign axis.bvalid = 0;
assign axis.wready = 0;
assign axis.awready = 0;
always_ff @(posedge clk or negedge rst_n)
if (~rst_n) begin
state <= WAIT;
axis.rvalid <= 0;
axis.arready <= 0;
end else begin
axis.arready <= 0;
unique case (state)
WAIT:
if (axis.arvalid & ~axis.arready)
state <= READ;
READ:
state <= RDATA;
RDATA: begin
state <= READY;
axis.rvalid <= 1;
end
READY:
if (axis.rready) begin
state <= WAIT;
axis.rvalid <= 0;
axis.arready <= 1;
end
endcase
end
always_ff @(posedge clk) begin
read <= rom[read_addr];
read_addr <= axis.araddr[$bits(read_addr) + SUBWORD_BITS - 1:SUBWORD_BITS];
axis.rdata <= read;
end
initial
$readmemh("gfx_bootrom.hex", rom);
endmodule
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