1 files changed, 81 insertions, 0 deletions
diff --git a/src/op/grow_memory.c b/src/op/grow_memory.c
new file mode 100644
index 0000000..9a2c203
--- /dev/null
+++ b/src/op/grow_memory.c
@@ -0,0 +1,81 @@
+/*
+ * 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 pop(struct nw_interp *const i)
+{
+    struct nw_i_sm_gm *const gm = &i->sm.gm;
+    const unsigned long max = i->cfg.m->out.linear.max;
+    const enum nw_state n = nwp_stack_pop(i, &gm->io);
+
+    if (n)
+        return n;
+    else if (gm->pages > max || i->linear.n_pages > max - gm->pages)
+    {
+        static const char *const exc = "cannot grow linear memory pages";
+
+        i->exception = exc;
+#ifdef NW_LOG
+        nwp_log("%s: %#lx\n", exc, (unsigned long)gm->pages);
+#endif
+        return NW_FATAL;
+    }
+
+    i->linear.n_pages += gm->pages;
+    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_gm *const gm = &i->sm.gm;
+    const struct nw_io_cfg *const cfg = &i->cfg.io;
+    const enum nw_state n = nwp_varuint1(cfg, &gm->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};
+
+        io.buf = &gm->pages;
+        io.n = sizeof gm->pages;
+        gm->io = io;
+    }
+
+    i->next = pop;
+    return NW_AGAIN;
+}
+
+void nwp_op_grow_memory(struct nw_interp *const i)
+{
+    static const struct nw_i_sm_gm gm;
+    struct nw_i_sm_gm *const pgm = &i->sm.gm;
+
+    *pgm = gm;
+    i->next = get_reserved;
+}