[VM] Added unit tests for integer arithmetic.

src/quest_editor/scripting/vm/index.test.ts

@@ -1,6 +1,73 @@
 import { VirtualMachine, ExecutionResult } from ".";
 import { VMIOStub } from "./VMIOStub";
 import { to_instructions } from "../../../../test/src/utils";
+import { Segment } from "../instructions";
+
+test("integer arithmetic opcodes", () => {
+    class TestIO extends VMIOStub {
+        error = jest.fn((err: Error, srcloc: any) => {
+            throw err;
+        });
+    }
+
+    const result_reg = 100;
+    const vm = new VirtualMachine(new TestIO());
+
+    function compute_arithmetic(obj_code: Segment[]): number {
+        vm.load_object_code(obj_code);
+        vm.start_thread(0);
+
+        let last_result: ExecutionResult;
+        do {
+            last_result = vm.execute();
+        } while (last_result !== ExecutionResult.Halted);
+
+        return vm.get_register_signed(result_reg);
+    }
+
+    function compute_arithmetic_with_register(opcode: string, val1: number, val2: number): number {
+        const other_reg = result_reg + 1;
+
+        const obj_code = to_instructions(`
+            0:
+                leti r${result_reg}, ${val1}
+                leti r${other_reg}, ${val2}
+                ${opcode} r${result_reg}, r${other_reg}`);
+
+        return compute_arithmetic(obj_code);
+    }
+
+    function compute_arithmetic_with_literal(opcode: string, val1: number, val2: number): number {
+        const obj_code = to_instructions(`
+            0:
+                leti r${result_reg}, ${val1}
+                ${opcode} r${result_reg}, ${val2}`);
+
+        return compute_arithmetic(obj_code);
+    }
+
+    // opcodes that use two register
+    expect(compute_arithmetic_with_register("add", 143, 656)).toBe(799);
+    expect(compute_arithmetic_with_register("sub", 4390, 11670)).toBe(-7280);
+    expect(compute_arithmetic_with_register("mul", 5356, 3)).toBe(16068);
+    expect(compute_arithmetic_with_register("div", 131, 130)).toBe(1);
+    expect(compute_arithmetic_with_register("mod", 5555555, 2)).toBe(1);
+
+    // opcodes that use one register and one literal
+    expect(compute_arithmetic_with_literal("addi", -3000, 5885858)).toBe(5882858);
+    expect(compute_arithmetic_with_literal("subi", 1, -1)).toBe(2);
+    expect(compute_arithmetic_with_literal("muli", 8008135, 0)).toBe(0);
+    expect(compute_arithmetic_with_literal("divi", 500, 100)).toBe(5);
+    expect(compute_arithmetic_with_literal("modi", 5959, 6969)).toBe(5959);
+
+    // special cases:
+    // integer overflow
+    expect(compute_arithmetic_with_register("add", 2147483647, 1)).toBe(-2147483648);
+    // under
+    expect(compute_arithmetic_with_register("sub", -2147483648, 4444)).toBe(2147479204);
+    // division by zero
+    expect(() => compute_arithmetic_with_register("div", 1, 0)).toThrow();
+});
 
 test("basic window_msg output", () => {
     const messages = ["foo", "bar", "buz"];