fix logic assign bugs

src/verilog/cpu/cpu_top.sv

@@ -54,7 +54,8 @@ module cpu_top (
   logic [9:0] branch_trgt;
   logic branch_taken;
 
-  logic [31:0] result = result_src ? dsram_rdata_i : alu_result;
+  logic [31:0] result;
+  assign result = result_src ? dsram_rdata_i : alu_result;
 
   logic ebreak_latch;
 

src/verilog/cpu/execute.sv

@@ -41,9 +41,11 @@ module execute (
     output logic [31:0] pc_target_o
 );
 
-  logic [31:0] a = rs1_data_i;
+  logic [31:0] a;
-  logic [31:0] b = alu_src_i ? imm_ext_i : rs2_data_i;
+  logic [31:0] b;
 
+  assign a = rs1_data_i;
+  assign b = alu_src_i ? imm_ext_i : rs2_data_i;
   assign pc_target_o = current_pc_i + imm_ext_i;
 
   alu alu (