Add if and else operators

1 files changed, 43 insertions, 0 deletions

diff --git a/src/op/if.c b/src/op/if.c
new file mode 100644
index 0000000..2ef9565
--- /dev/null
+++ b/src/op/if.c
@@ -0,0 +1,43 @@
+/*
+ * 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/ops.h>
+#include <nw/routines.h>
+#include <nw/stack.h>
+#include <nw/types.h>
+
+static enum nw_state pop(struct nw_interp *const i)
+{
+    struct nw_i_sm_if *const pif = &i->sm.sm_if;
+    const enum nw_state n = nwp_stack_pop(i, &pif->io);
+
+    if (n)
+        return n;
+    else if (pif->condition)
+        nwp_interp_resume(i);
+    else
+        nwp_break(i, 0);
+
+    return NW_AGAIN;
+}
+
+void nwp_op_if(struct nw_interp *const i)
+{
+    static const struct nw_i_sm_if sm_if;
+    struct nw_i_sm_if *const pif = &i->sm.sm_if;
+    struct nw_sm_io *const io = &pif->io;
+
+    *pif = sm_if;
+    io->buf = &pif->condition;
+    io->n = sizeof pif->condition;
+    nwp_start_block(i, &pif->sb, pop);
+}