From 6b865a70c0f29e5ca9e13fae4a2a18406f44f4ee Mon Sep 17 00:00:00 2001
From: Xavier Del Campo Romero <xavi92@disroot.org>
Date: Mon, 10 Nov 2025 23:47:36 +0100
Subject: Add current_memory and grow_memory operators

---
 src/op/current_memory.c | 70 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 70 insertions(+)
 create mode 100644 src/op/current_memory.c

(limited to 'src/op/current_memory.c')

diff --git a/src/op/current_memory.c b/src/op/current_memory.c
new file mode 100644
index 0000000..d7ce395
--- /dev/null
+++ b/src/op/current_memory.c
@@ -0,0 +1,70 @@
+/*
+ * 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>
+
+static enum nw_state push(struct nw_interp *const i)
+{
+    struct nw_i_sm_cm *const cm = &i->sm.cm;
+    const enum nw_state n = nwp_stack_push(i, &cm->io);
+
+    if (n)
+        return n;
+
+    nwp_interp_resume(i);
+    return NW_AGAIN;
+}
+
+static enum nw_state get_reserved(struct nw_interp *const i)
+{
+    nw_varuint1 reserved;
+    struct nw_i_sm_cm *const cm = &i->sm.cm;
+    const struct nw_io_cfg *const cfg = &i->cfg.io;
+    const enum nw_state n = nwp_varuint1(cfg, &cm->leb128, &reserved, cfg->user);
+
+    if (n)
+        return n;
+    else if (reserved)
+    {
+        static const char *const exc = "invalid reserved value";
+
+        i->exception = exc;
+#ifdef NW_LOG
+        nwp_log("%s: %#x\n", exc, (unsigned)reserved);
+#endif
+        return NW_FATAL;
+    }
+    else
+    {
+        struct nw_sm_io io = {0};
+        nw_varuint32 *const np = &i->linear.n_pages;
+
+        io.buf = np;
+        io.n = sizeof *np;
+        cm->io = io;
+    }
+
+    i->next = push;
+    return NW_AGAIN;
+}
+
+void nwp_op_current_memory(struct nw_interp *const i)
+{
+    static const struct nw_i_sm_cm cm;
+    struct nw_i_sm_cm *const pcm = &i->sm.cm;
+
+    *pcm = cm;
+    i->next = get_reserved;
+}
-- 
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