on april 22, 2013 embarcadero released rad studio xe4, which included delphi xe4, and c++builder. there has been no major upgrade for either embarcadero prism or html5 builder thence. delphi xe4 is the first release of the firemonkey mobile platform, featuring cross-platform mobile application development for the ios simulator and ios devices. in this version embarcadero introduces two new compilers for delphi mobile applications, the delphi cross compiler for the ios simulator and the delphi cross compiler for the ios devices. these compilers significantly differ from the win64 desktop compiler as they do not support com, inline assembly of cpu instructions, and six older string types such as pchar. the new mobile compilers advance the notion of eliminating pointers. the new compilers require an explicit style of marshalling data to and from external apis and libraries. delphi xe4 run-time library (rtl) is optimized for 0-based, read-only (immutable) unicode strings, that cannot be indexed for the purpose of changing their individual characters. the rtl also adds status-bit based exception routines for arm cpus that do not generate exception interrupts.