Little-endian - Endianness and Hardware - Floating-point and Endianness

Floating-point and Endianness

Although the ubiquitous x86 of today use little-endian storage for all types of data (integer, floating point, BCD), there have been a few historical machines where floating point numbers were represented in big-endian form while integers were represented in little-endian form. There are old ARM processors that have half little-endian, half big-endian floating point representation. Because there have been many floating point formats with no "network" standard representation for them, there is no formal standard for transferring floating point values between heterogeneous systems. It may therefore appear strange that the widespread IEEE 754 floating point standard does not specify endianness. Theoretically, this means that even standard IEEE floating point data written by one machine might not be readable by another. However, on modern standard computers (i.e., implementing IEEE 754), one may in practice safely assume that the endianness is the same for floating point numbers as for integers, making the conversion straightforward regardless of data type. (Small embedded systems using special floating point formats may be another matter however.)