1 files changed, 98 insertions, 0 deletions
diff --git a/src/op/br_table.c b/src/op/br_table.c
new file mode 100644
index 0000000..2737c0d
--- /dev/null
+++ b/src/op/br_table.c
@@ -0,0 +1,98 @@
+/*
+ * 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/ops.h>
+#include <nw/routines.h>
+#include <nw/stack.h>
+#include <nw/types.h>
+
+static enum nw_state get_target(struct nw_interp *const i)
+{
+    nw_varuint32 target;
+    struct nw_i_sm_br_table *const b = &i->sm.br_table;
+    const struct nw_io_cfg *const cfg = &i->cfg.io;
+    const enum nw_state n = nwp_varuint32(cfg, &b->leb128, &target, cfg->user);
+
+    if (n)
+        return n;
+    else if (b->target_i == b->offset
+        || (!b->set && b->target_i >= b->target_count))
+    {
+        b->set = 1;
+        b->relative_depth = target;
+    }
+
+    if (b->target_i >= b->target_count)
+        nwp_break(i, b->relative_depth, b->offset);
+    else
+        b->target_i++;
+
+    return NW_AGAIN;
+}
+
+static enum nw_state pop(struct nw_interp *const i)
+{
+    struct nw_i_sm_br_table *const b = &i->sm.br_table;
+    const enum nw_state n = nwp_stack_pop(i, &b->io);
+
+    if (n)
+        return n;
+
+    i->next = get_target;
+    return NW_AGAIN;
+}
+
+static enum nw_state get_target_count(struct nw_interp *const i)
+{
+    struct nw_i_sm_br_table *const b = &i->sm.br_table;
+    const struct nw_io_cfg *const cfg = &i->cfg.io;
+    const enum nw_state n = nwp_varuint32(cfg, &b->leb128,
+        &b->target_count, cfg->user);
+    const enum nw_type pt = i->push_type;
+
+    if (n)
+        return n;
+    else if (pt != NW_TYPE_I32)
+    {
+        static const char *const exc = "expected i32 expression for br_table";
+        const char *const stype = nwp_type_str(pt);
+
+        i->exception = exc;
+#ifdef NW_LOG
+        if (stype)
+            nwp_log("%s, got: %s\n", exc, stype);
+        else
+            nwp_log("%s, got: unknown (%#x)\n", exc, (unsigned)pt);
+#endif
+        return NW_FATAL;
+    }
+    else
+    {
+        struct nw_sm_io io = {0};
+
+        io.buf = &b->offset;
+        io.n = sizeof b->offset;
+        b->io = io;
+        i->next = pop;
+    }
+
+    return NW_AGAIN;
+}
+
+void nwp_op_br_table(struct nw_interp *const i)
+{
+    static const struct nw_i_sm_br_table b;
+
+    i->next = get_target_count;
+    i->sm.br_table = b;
+}