cpu: Add core and fetch unit groundworkmain

Signed-off-by: Ian M. <ian@patel.org>

1 files changed, 48 insertions, 0 deletions

diff --git a/rtl/cpu/cpu_fetch.sv b/rtl/cpu/cpu_fetch.sv
new file mode 100644
index 0000000..00fcbd0
--- /dev/null
+++ b/rtl/cpu/cpu_fetch.sv
@@ -0,0 +1,48 @@
+//
+// Copyright (c) 2026, Apollo Telephone Laboratories.
+// Provided under the BSD-3 clause.
+//
+
+`include "bus/ari.svh"
+
+//
+// Represents a CPU fetch
+//
+module cpu_fetch (
+    input wire clk_i,
+    input wire reset_i,
+    input wire memop_done_i,
+
+    output logic mem_req_o,
+    output logic [PMA_XLEN-1:0] mem_ad_o
+);
+    parameter FSM_STAGE_REQUEST   = 0;
+    parameter FSM_STAGE_WAIT      = 1;
+
+    logic [63:0] pc;
+    logic [2:0] fsm_stage;
+
+    always_ff @(posedge clk_i) begin
+        if (reset_i) begin
+            mem_req_o   <= 0;
+            mem_ad_o    <= 0;
+            pc          <= 0;
+            fsm_stage   <= 0;
+        end else begin
+            case (fsm_stage)
+                FSM_STAGE_REQUEST: begin
+                    mem_ad_o  <= pc;
+                    mem_req_o <= 1;
+                    fsm_stage <= FSM_STAGE_WAIT;
+                end
+                FSM_STAGE_WAIT: begin
+                    if (memop_done_i) begin
+                        mem_req_o  <= 0;
+                        pc         <=  pc + 4;
+                        fsm_stage  <= FSM_STAGE_REQUEST;
+                    end
+                end
+            endcase
+        end
+    end
+endmodule