feat(L05): add ALU assembler and execute card

src/tasks/task01_alu_core.sv

@@ -0,0 +1,25 @@
+module alu_core (
+    input logic [31:0] operand_a, operand_b,
+    input logic [3:0] operation,
+    output logic [31:0] result,
+    output logic zero
+);
+    localparam logic [3:0] ADD=0, SUB=1, AND_OP=2, OR_OP=3, XOR_OP=4,
+        SLL_OP=5, SRL_OP=6, SRA_OP=7, SLT_OP=8, SLTU_OP=9;
+    always_comb begin
+        unique case (operation)
+            ADD:     result = operand_a + operand_b;
+            SUB:     result = operand_a - operand_b;
+            AND_OP:  result = operand_a & operand_b;
+            OR_OP:   result = operand_a | operand_b;
+            XOR_OP:  result = operand_a ^ operand_b;
+            SLL_OP:  result = operand_a << operand_b[4:0];
+            SRL_OP:  result = operand_a >> operand_b[4:0];
+            SRA_OP:  result = $signed(operand_a) >>> operand_b[4:0];
+            SLT_OP:  result = {31'b0, $signed(operand_a) < $signed(operand_b)};
+            SLTU_OP: result = {31'b0, operand_a < operand_b};
+            default: result = 32'b0;
+        endcase
+    end
+    assign zero = result == 0;
+endmodule