Source: The Korea Times
quote: A 64 bit processor handles large floating point calculations a lot faster than a 32 bit one does.
quote: It also provides a lot more CPU registers, and it increases the size of those registers; most 32 bit chips are somewhat constrained in this area.
quote: And lastly, the one everyone seems to get hung up on, it allows for clean addressing of 4+ GB of ram. Microsoft got caught with their pants down in the PC world on this one. People buying PC's with 4 GB of RAM, but OS could only use 3.0 GB, or maybe 3.2 GB, because OS was only 32 bit. High end phones already have 2 GB of RAM. It makes sense to begin transitioning them to 64 bit *now* so that in a year or two, when 4 GB phones hit the market, you won't be stuck with only 3.2 GB usable.
quote: An obvious reason for 64-bit is the support of more than 4GB of physical memory; however this is achieved in ARMv7’s LPAE extension on Cortex-A15 and Cortex-A7. Why then is 64-bit useful?In server applications, OS and application software are frequently 64-bit today, so 64-bit pointers for virtual addressing are critical in these applications. Full support of AArch64, in addition to the power efficient ARMv8 architecture and power optimized microarchitectures, make Cortex-A50 series processors well suited to a broad range of applications in efficient low-power servers.In the desktop environment, a larger virtual address space is important for modern desktop software APIs that may come to rely on having a vast virtual address space for techniques such as memory mapped file I/O and sparse addressing (e.g. for persistent objects). AArch64 also enables efficient 64-bit immediate generation meaning less need for literal pools.A large program counter relative addressing range (+/-4GB) for efficient data addressing is helpful within shared libraries and position-independent executable. The ARMv8 instruction set, fully supported by the Cortex-A50 series processors, is optimized for clean code generation, with its orthogonal ISA and compiler friendly flexible addressing modes.Support for 64-bit in ARMv8 will enable ARM processors to become more broadly deployed in server and desktop applications, and will provide future-proof support for the eventual migration of 64-bit operating systems to mobile applications.
quote: The Cortex-A50 Series is the latest range of processors based on the ARMv8 architecture. The series includes support for the AArch64, a new energy efficient 64-bit execution state that operates alongside an enhanced version of ARM’s existing 32-bit execution state.Cortex-A50 series processors are excellent 32-bit processors with 64-bit capability. They deliver more performance for ARMv7 32-bit code in AArch32 execution state, and offer support for 64-bit data and larger virtual addressing space in AArch64 execution state.