Implement RLA and POP RR

rtl/shared/ram.sv

@@ -0,0 +1,34 @@
+module ram #(
+    parameter DATA_W = 8,
+    parameter ADDR_W = 8
+)(
+    input  logic              clk_i,
+
+    input  logic              cs_i,
+
+    input  logic [ADDR_W-1:0] address_i,
+    input  logic              we_i,
+    input  logic [DATA_W-1:0] wdata_i,
+    output logic [DATA_W-1:0] rdata_o
+);
+
+localparam RAM_SIZE = 2**ADDR_W;
+
+logic [DATA_W-1:0] ram [RAM_SIZE-1:0];
+
+logic              wenable;
+logic [DATA_W-1:0] rdata;
+
+assign wenable = cs_i & we_i;
+
+always_ff @(posedge clk_i)
+    if (wenable)
+        ram[address_i] <= wdata_i;
+
+always_ff @(posedge clk_i)
+    if (cs_i)
+        rdata <= ram[address_i];
+
+assign rdata_o = {DATA_W{cs_i}} & rdata;
+
+endmodule

rtl/shared/rom.sv

@@ -4,6 +4,7 @@ module rom #(
     parameter integer unsigned DATA_W = 8
 ) (
     input  logic              clk_i,
+    input  logic              cs_i,
     input  logic [ADDR_W-1:0] address_i,
 
     output logic [DATA_W-1:0] rdata_o
@@ -12,9 +13,13 @@ module rom #(
 localparam ROM_SIZE = 2**ADDR_W;
 
 logic [DATA_W-1:0] rom [ROM_SIZE-1:0];
+logic [DATA_W-1:0] rdata;
 
 always_ff @(posedge clk_i)
-    rdata_o <= rom[address_i];
+    if (cs_i)
+        rdata <= rom[address_i];
+
+assign rdata_o = {DATA_W{cs_i}} & rdata;
 
 initial begin
     static integer fd = $fopen(FILE_NAME, "rb");