diff --git a/osaca/parser/parser_AArch64.py b/osaca/parser/parser_AArch64.py
index 2504e50..d6467cb 100755
--- a/osaca/parser/parser_AArch64.py
+++ b/osaca/parser/parser_AArch64.py
@@ -417,10 +417,7 @@ class ParserAArch64(BaseParser):
             # arithmetic immediate, add calculated value as value
             immediate['shift'] = immediate['shift'][0]
             immediate['value'] = (
-                int(
-                    immediate['base_immediate']['value'],
-                    16 if immediate['base_immediate']['value'].lower().startswith('0x') else 10
-                ) << int(immediate['shift']['value'])
+                int(immediate['base_immediate']['value'], 0) << int(immediate['shift']['value'])
             )
             return AttrDict({self.IMMEDIATE_ID: immediate})
         if 'float' in immediate: