Add write enable output to the memory bus

This will be used by the bus arbiter and the hazard unit. We could use
the write_mask output, but this would introduce a longer delay.

rv32.sv

@@ -13,6 +13,7 @@ module rv32 (
     /* data memory bus */
     output logic [31:0] data_address_out,
     output logic data_read_out,
+    output logic data_write_out,
     input [31:0] data_read_value_in,
     output logic [3:0] data_write_mask_out,
     output logic [31:0] data_write_value_out
@@ -260,6 +261,7 @@ module rv32 (
 
         /* control out (to memory bus) */
         .data_read_out(data_read_out),
+        .data_write_out(data_write_out),
         .data_write_mask_out(data_write_mask_out),
 
         /* data out */

rv32_mem.sv

@@ -38,6 +38,7 @@ module rv32_mem (
 
     /* control out (to data memory bus) */
     output logic data_read_out,
+    output logic data_write_out,
     output logic [3:0] data_write_mask_out,
 
     /* data out */
@@ -62,6 +63,7 @@ module rv32_mem (
     assign branch_pc_out = branch_pc_in;
 
     assign data_read_out = read_in;
+    assign data_write_out = write_in;
     assign data_address_out = result_in;
 
     always_comb begin