2 files changed, 43 insertions(+), 7 deletions(-)

M src/ram.sv
M testbench/tb_cpu_program.sv

@@ 7,9 7,14 @@ module ram (
   output [31:0] rd);
 
   reg [31:0]      mask;
-  reg [31:0]      memory[128];
+  reg [31:0]      memory[1023];
 
-  assign rd = memory[a[8:2]]; // word aligned
+  assign rd = memory[a[11:2]]; // word aligned
+
+  parameter        LOAD_FILE = 0;
+  parameter string LOAD_FILE_PATH = "";
+  parameter        WRITE_FILE = 0;
+  parameter string WRITE_FILE_PATH = "";
 
   always_comb begin
     mask = {


@@ 20,8 25,23 @@ module ram (
             };
   end
 
+  initial
+    if (LOAD_FILE == 1) begin
+      $display("Loading file %s into memory.", LOAD_FILE_PATH);
+      $readmemh(LOAD_FILE_PATH, memory);
+    end
+
+  initial begin
+    if (WRITE_FILE == 1) begin
+      wait (a == {32{1'b1}});
+      #5
+      $display("Writing memory to file %s.", WRITE_FILE_PATH);
+      $writememh(WRITE_FILE_PATH, memory);
+    end
+  end
+
   always_ff @ (posedge clk)
     if(we)
-      memory[a[8:2]] = (rd & ~mask) | (wd & mask);
+      memory[a[11:2]] = (rd & ~mask) | (wd & mask);
 
 endmodule

@@ 3,7 3,7 @@ import cpu_types::*;
 module tb_cpu_program();
   reg clk, rst_n;
 
-  wire [31:0] memory_address, memory_write, memory_out;
+  wire [31:0] memory_address, cpu_memory_address, memory_write, memory_out;
   wire [3:0]  memory_write_byte_enable;
   wire        memory_we;
 


@@ 15,6 15,14 @@ module tb_cpu_program();
   parameter string  CPU_PROGRAM_PATH;
   parameter string  CPU_PROGRAM_NAME;
 
+  parameter         MEMORY_LOAD_FILE = 0;
+  parameter string  MEMORY_LOAD_FILE_PATH = "";
+  parameter         MEMORY_WRITE_FILE = 0;
+  parameter string  MEMORY_WRITE_FILE_PATH = "";
+
+  // assign 0xFF... when ebreak. To save the memory to a file.
+  assign memory_address = ebreak == 1'b1 ? {32{1'b1}} : cpu_memory_address;
+
   cpu uut(
     .clk(clk),
     .rst_n(rst_n),


@@ 22,7 30,7 @@ module tb_cpu_program();
     .instruction(instruction),
     .pc(pc),
 
-    .memory_address(memory_address),
+    .memory_address(cpu_memory_address),
     .memory_out(memory_out),
     .memory_write(memory_write),
     .memory_byte_enable(memory_write_byte_enable),


@@ 31,7 39,12 @@ module tb_cpu_program();
     .ebreak(ebreak)
   );
 
-  ram memory_inst(
+  ram #(
+    .LOAD_FILE(MEMORY_LOAD_FILE),
+    .LOAD_FILE_PATH(MEMORY_LOAD_FILE_PATH),
+    .WRITE_FILE(MEMORY_WRITE_FILE),
+    .WRITE_FILE_PATH(MEMORY_WRITE_FILE_PATH)
+  ) memory_inst(
     .clk(clk),
     .a(memory_address),
     .write_byte_enable(memory_write_byte_enable),


@@ 40,12 53,15 @@ module tb_cpu_program();
     .rd(memory_out)
   );
 
-  file_program_memory #(.FILE_NAME(CPU_PROGRAM_PATH)) prog_mem_inst(
+  file_program_memory #(
+    .FILE_NAME(CPU_PROGRAM_PATH)
+  ) prog_mem_inst(
     .addr(pc[11:0]),
     .instruction(instruction)
   );
 
   always_ff @ (posedge ebreak) begin
+    $display("ebreak!");
     #15 $finish;
   end