Data formats[edit]
Sixteen-bit words are stored little-endian (with least significant bytes first). Thirty-two-bit data—supported as extensions to the basic architecture, e.g., floating point in the FPU Instruction Set, double-words in the Extended Instruction Set or long data in the Commercial Instruction Set—are stored in more than one format, including an unusual middle-endian format[2][3] sometimes referred to as "PDP-endian".