1 files changed, 49 insertions, 0 deletions
diff --git a/src/routines/start_block.c b/src/routines/start_block.c
new file mode 100644
index 0000000..83be44c
--- /dev/null
+++ b/src/routines/start_block.c
@@ -0,0 +1,49 @@
+/*
+ * nanowasm, a tiny WebAssembly/Wasm interpreter
+ * Copyright (C) 2023-2025  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/interp.h>
+#include <nw/io.h>
+#include <nw/log.h>
+#include <nw/routines.h>
+#include <nw/types.h>
+
+static enum nw_state get_block_type(struct nw_interp *const i)
+{
+    nw_varint7 type;
+    struct nw_i_sm_sb *const sb = &i->sm.start_block;
+    const struct nw_io_cfg *const cfg = &i->cfg.io;
+    const enum nw_state n = nwp_varint7(cfg, &sb->leb128, &type, cfg->user);
+    enum nw_type block_type;
+
+    if (n)
+        return n;
+    else if (type != 0x40 && nwp_get_type(type, &block_type))
+    {
+        static const char *const exc = "invalid block_type";
+
+        i->exception = exc;
+#ifdef NW_LOG
+        nwp_log("%s: %#hhx\n", exc, (unsigned char)type);
+#endif
+        return NW_FATAL;
+    }
+
+    i->fr.block_i++;
+    nwp_interp_resume(i);
+    return NW_AGAIN;
+}
+
+void nwp_start_block(struct nw_interp *const i)
+{
+    const struct nw_i_sm_sb sb = {0};
+
+    i->sm.start_block = sb;
+    i->next = get_block_type;
+}