Refactored all OP_ functions to vm/CATEGORY/ and renamed the files.

src/vm/core/call.c

@@ -0,0 +1,25 @@
+case OP_CALL: {
+    int argc = inst.operand;
+    if (argc < 0) argc = 0;
+    /* collect args in reverse (preserve order) */
+    Value *args = NULL;
+    if (argc > 0) {
+        args = (Value*)malloc(sizeof(Value) * argc);
+        /* pop args into array in reverse */
+        for (int i = argc - 1; i >= 0; --i) {
+            args[i] = pop_value(vm);
+        }
+    }
+    /* pop function value */
+    Value fnv = pop_value(vm);
+    if (fnv.type != VAL_FUNCTION) {
+        fprintf(stderr, "Runtime type error: CALL expects function\n");
+        exit(1);
+    }
+    /* push new frame and transfer args */
+    vm_push_frame(vm, fnv.fn, argc, args);
+    /* free args array (locals moved), free fnv (no-op for function) */
+    free(args);
+    /* note: fnv contains a pointer to the Bytecode, don't free here */
+    break;
+}