added memory unit

1 files changed, 58 insertions, 0 deletions

diff --git a/src/memory_unit.v b/src/memory_unit.v
new file mode 100644
index 0000000..7eb435b
--- /dev/null
+++ b/src/memory_unit.v
@@ -0,0 +1,58 @@
+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