Complex sentence: The recently introduced ARMv8-A architecture add support for a 64-bit address space and 64-bit arithmetic; it was first implemented in the Apple A7 in the iPhone 5S.
Split into simpler sentences: The recently introduced ARMv8-A architecture add support for a 64-bit address space and 64-bit arithmetic. Apple first implemented the ARMv8-A architecture in the Apple A7 chip in the iPhone 5S.