Increase prefetch depth from 3 to 4

Makefile

@@ -28,7 +28,7 @@ tbs =  $(wildcard tb/*_tb.sv)
 # Search here for include files (e.g.: non-standalone components)
 incdir = ./includes
 # Test case to run
-test_case = alu_test
+test_case = core_test
 # QuestaSim Version
 questa_version = -10.5c
 compile_flag = +cover=bcfst+/dut

src/fetch_fifo.sv

@@ -49,7 +49,7 @@ module fetch_fifo
                                            // included. This signal is available immediately as it comes directly out of FFs
   );
 
-  localparam DEPTH = 3; // must be 3 or greater
+  localparam DEPTH = 4; // must be 3 or greater
   /* verilator lint_off LITENDIAN */
   // index 0 is used for output
   logic [0:DEPTH-1] [63:0]  addr_n,    addr_int,    addr_Q;

tb/scoreboard_tb.sv

@@ -110,7 +110,6 @@ module scoreboard_tb;
 
                 @(scoreboard_if.mck);
 
-                // if we are not full then load another instruction
                 if (scoreboard_if.issue_instr_valid == 1'b1) begin
                     scoreboard_if.mck.issue_ack <= 1'b1;
                     issue_instruction <= scoreboard_if.mck.issue_instr;