1 files changed, 100 insertions, 0 deletions
diff --git a/src/op/variable_access/get_global.c b/src/op/variable_access/get_global.c
new file mode 100644
index 0000000..d38f2d0
--- /dev/null
+++ b/src/op/variable_access/get_global.c
@@ -0,0 +1,100 @@
+/*
+ * nanowasm, a tiny WebAssembly/Wasm interpreter
+ * Copyright (C) 2023-2024  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 <nw/log.h>
+#include <nw/interp.h>
+#include <nw/ops.h>
+#include <nanowasm/nw.h>
+#include <nw/types.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <string.h>
+
+static int get_i32(struct nw_interp *const i, const void *const src)
+{
+    return interp_stack_push(i, src, sizeof (int32_t));
+}
+
+static int get_i64(struct nw_interp *const i, const void *const src)
+{
+    return interp_stack_push(i, src, sizeof (int64_t));
+}
+
+static int get_f32(struct nw_interp *const i, const void *const src)
+{
+    return interp_stack_push(i, src, sizeof (float));
+}
+
+static int get_f64(struct nw_interp *const i, const void *const src)
+{
+    return interp_stack_push(i, src, sizeof (double));
+}
+
+static int get_global(struct nw_interp *const i, const varuint32 global_index)
+{
+    struct nw_gframe *gfr;
+    varuint32 idx;
+
+    for (idx = global_index, gfr = i->gfp; gfr; gfr = gfr->next)
+        if (idx == global_index)
+            break;
+
+    if (!gfr)
+    {
+        LOG("%s: cannot access global variable %lu\n", __func__,
+            (unsigned long)global_index);
+        i->exception = "global variable index out of bounds";
+        return -1;
+    }
+
+    static int (*const get[])(struct nw_interp *, const void *) =
+    {
+        [VALUE_TYPE_I32] = get_i32,
+        [VALUE_TYPE_I64] = get_i64,
+        [VALUE_TYPE_F32] = get_f32,
+        [VALUE_TYPE_F64] = get_f64,
+    };
+
+    if (get[gfr->type](i, gfr + 1))
+    {
+        LOG("%s: get type %s failed\n", __func__, value_type_tostr(gfr->type));
+        return -1;
+    }
+
+    return 0;
+}
+
+static int op(struct nw_interp *const i, FILE *const f)
+{
+    varuint32 global_index;
+
+    if (varuint32_read(f, &global_index))
+    {
+        LOG("%s: varuint32_read failed\n", __func__);
+        return 1;
+    }
+    else if (i && get_global(i, global_index))
+    {
+        LOG("%s: get_global failed\n", __func__);
+        return -1;
+    }
+
+    return 0;
+}
+
+int op_get_global(struct nw_interp *const i)
+{
+    return op(i, i->f);
+}
+
+int check_get_global(FILE *const f)
+{
+    return op(NULL, f);
+}