1 files changed, 39 insertions, 0 deletions
diff --git a/src/op/check/br_if.c b/src/op/check/br_if.c
new file mode 100644
index 0000000..6e6bd10
--- /dev/null
+++ b/src/op/check/br_if.c
@@ -0,0 +1,39 @@
+/*
+ * nanowasm, a tiny WebAssembly/Wasm interpreter
+ * Copyright (C) 2023-2024  Xavier Del Campo Romero
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
+#include <nanowasm/nw.h>
+#include <nw/io.h>
+#include <nw/log.h>
+#include <nw/ops.h>
+
+static enum nw_state get_relative_depth(struct nw_mod *const m)
+{
+    nw_varuint32 relative_depth;
+    const struct nw_io_cfg *const cfg = &m->cfg.io;
+    struct nw_sm_c *const c = &m->sm.code;
+    struct nw_sm_leb128 *const l = &c->leb128;
+    const enum nw_state n = nwp_varuint32(cfg, l, &relative_depth);
+
+    if (n)
+        return n;
+    else if (relative_depth >= c->fn.blocks)
+    {
+        LOG("%s: invalid relative depth %lu\n", __func__,
+            (unsigned long)relative_depth);
+        return NW_FATAL;
+    }
+
+    m->next = c->next;
+    return NW_AGAIN;
+}
+
+void nwp_op_check_br_if(struct nw_mod *const m)
+{
+    m->next = get_relative_depth;
+}