Types of endianness

Question

What is the difference between the following types of endianness?

• byte (8b) invariant big and little endianness
• half-word (16b) invariant big and litt

Answer 1

Actually, I'd describe the endianness of a machine as the order of bytes inside of a word, and not the order of bits.

By "bytes" up there I mean the "smallest unit of memory the architecture can manage individually". So, if the smallest unit is 16 bits long (what in x86 would be called a word) then a 32 bit "word" representing the value 0xFFFF0000 could be stored like this:

FFFF 0000

or this:

0000 FFFF

in memory, depending on endianness.

So, if you have 8-bit endianness, it means that every word consisting of 16 bits, will be stored as:

FF 00

or:

00 FF

and so on.