First commit

1 files changed, 125 insertions, 0 deletions

diff --git a/src/routines/find_local.c b/src/routines/find_local.c
new file mode 100644
index 0000000..e5ab9d2
--- /dev/null
+++ b/src/routines/find_local.c
@@ -0,0 +1,125 @@
+/*
+ * 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/log.h>
+#include <nw/routines.h>
+#include <nw/stack.h>
+#include <nw/types.h>
+#include <limits.h>
+
+static enum nw_state read_meta(struct nw_interp *const i)
+{
+    struct nw_find_local *const f = i->state;
+    const struct nw_local_meta *const m = &f->meta;
+    const nw_varuint32 index = f->index - f->entry_i;
+    const enum nw_state n = nwp_stack_read(i, &f->io, f->addr);
+    size_t sz;
+    nw_varuint32 count;
+
+    if (n)
+        return n;
+
+    f->addr += sizeof f->meta;
+    count = m->entry_count;
+
+    if (nwp_type_sz(m->type, &sz))
+    {
+        static const char *const exc = "invalid type";
+
+        i->exception = exc;
+#ifdef NW_LOG
+        nwp_log("%s: %#x\n", exc, (unsigned)m->type);
+#endif
+        return NW_FATAL;
+    }
+    else if (index < count)
+    {
+        const size_t offset = sz * index;
+
+        if (f->addr > ULONG_MAX - offset)
+        {
+            static const char *const exc = "out-of-bounds access to local";
+
+            i->exception = exc;
+#ifdef NW_LOG
+            nwp_log("%s: addr: %lu, offset: %lu\n", exc,
+                (unsigned long)f->addr, (unsigned long)offset);
+#endif
+            return NW_FATAL;
+        }
+        else if ((f->addr += offset) >= i->fr.local_end)
+        {
+            static const char *const exc = "invalid local index";
+
+            i->exception = exc;
+#ifdef NW_LOG
+            nwp_log("%s: %lu\n", exc, (unsigned long)f->index);
+#endif
+            return NW_FATAL;
+        }
+
+        i->next = f->next;
+    }
+    else
+    {
+        const size_t offset = sz * count;
+
+        f->entry_i += count;
+
+        if (f->addr > ULONG_MAX - offset)
+        {
+            static const char *const exc = "out-of-bounds access to local";
+
+            i->exception = exc;
+#ifdef NW_LOG
+            nwp_log("%s: addr: %lu, offset: %lu\n", exc,
+                (unsigned long)f->addr, (unsigned long)offset);
+#endif
+            return NW_FATAL;
+        }
+        else if ((f->addr += offset) >= i->fr.local_end)
+        {
+            static const char *const exc = "invalid local index";
+
+            i->exception = exc;
+#ifdef NW_LOG
+            nwp_log("%s: %lu\n", exc, (unsigned long)f->index);
+#endif
+            return NW_FATAL;
+        }
+        else
+        {
+            struct nw_sm_io io = {0};
+
+            io.buf = &f->meta;
+            io.n = sizeof f->meta;
+            f->io = io;
+        }
+    }
+
+    return NW_AGAIN;
+}
+
+void nwp_find_local(struct nw_interp *const i, struct nw_find_local *const f,
+    const nw_varuint32 index, enum nw_state (*const next)(struct nw_interp *),
+    void *const args)
+{
+    const struct nw_find_local fl = {0};
+
+    *f = fl;
+    f->index = index;
+    f->next = next;
+    f->addr = i->fr.local_start;
+    f->io.buf = &f->meta;
+    f->io.n = sizeof f->meta;
+    i->state = f;
+    i->args = args;
+    i->next = read_meta;
+}