ARM processor

ARM is a family of RISC (Reduced Instruction Set Computers) architectures. VLSI devices are not manufactured by ARM; instead it gives license to other companies. ARM instructions in assembly language are written one per line, starting after the first column. A semicolon is used to start comments and the label which represents the memory location is written at the beginning of the line, starting in the first column. There exist different versions of ARM architecture. ARM7 is a von Neumann architecture machine which allows addresses up to 32 bits long. Harvard architecture is used in ARM9. The configuration of ARM processor is possible in two modes – little-endian mode and big-endian mode. In little-endian mode, lowest order byte is stored in the lower order bits of the word and in big-endian mode; lowest order byte is stored in the highest bits of the word. Arithmetic and logical operations cannot be performed directly on memory locations in an ARM processor.