Add mapped address output and test

hw/efinix_fpga/src/mapper.sv

@@ -13,12 +13,20 @@ logic [15:0] mm [16];
 
 logic [31:0] we;
 
+
+// TODO These have basically the same name.
 logic [15:0] mm_sel;
 
+logic [15:0] selected_mm;
+
 always_comb begin
     we = (i_we << i_cpu_addr[4:0]);
 
+    mm_sel = (1 << i_cpu_addr[4:1]);
     o_data = mm_sel[8*i_cpu_addr[0] +: 8];
+
+    selected_mm = mm[i_cpu_addr[15:12]];
+    o_mapped_addr = {selected_mm[12:0], i_cpu_addr[11:0]};
 end
 
 always_ff @(negedge i_clk or posedge i_reset) begin