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module memory_unit #(
parameter N = 32
)(
input clk,
input rst,
input we,
input [N-1:0] addr,
output reg [N-1:0] data_read,
input [N-1:0] data_write
);
reg we_ram;
wire [N-1:0] data_read_ram, data_read_rom;
ram #(.N(N), .SIZE(1024)) ram(
.clk(clk),
.rst(rst),
.we(we_ram),
.addr(addr[N-17:0]),
.data_read(data_read_ram),
.data_write(data_write)
);
rom #(.N(N), .SIZE(1024)) rom(
.clk(clk),
.rst(rst),
.addr(addr[N-17:0]),
.data_read(data_read_rom)
);
// 0000 0000 Reserved
// 0000 FFFF
//
// 0001 0000 ROM
// 000F FFFF
//
// 0010 0000 RAM
// FF0F FFFF
//
// FF10 0000 Reserved
// FFFF FFFF
always @(*) begin
we_ram = 0;
if (addr[N-1:N-16] == 16'h0000) begin
data_read <= 0;
end else if (addr[N-1:N-16] >= 16'h0001 && addr[N-1:N-16] <= 16'h000F) begin
data_read <= data_read_rom;
we_ram = we;
end else if (addr[N-1:N-16] >= 16'h0010 && addr[N-1:N-16] <= 16'hFF0F) begin
data_read <= data_read_ram;
end else if (addr[N-1:N-16] >= 16'hFF10 && addr[N-1:N-16] <= 16'hFFFF) begin
data_read <= 0;
end
end
endmodule
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