Endian

Depending on which computing system you use, you will have to consider the byte order in which multibyte numbers are stored, particularly when you are writing those numbers to a file. The two orders are called "Little Endian" and "Big Endian".

The Basics

"Little Endian" means that the low-order byte of the number is stored in memory at the lowest address, and the high-order byte at the highest address. (The little end comes first.) For example, a 4 byte LongInt

    Byte3 Byte2 Byte1 Byte0

will be arranged in memory as follows:

    Base Address+0   Byte0
   Base Address+1   Byte1
   Base Address+2   Byte2
   Base Address+3   Byte3

Intel processors (those used in PC's) use "Little Endian" byte order.

"Big Endian" means that the high-order byte of the number is stored in memory at the lowest address, and the low-order byte at the highest address. (The big end comes first.) Our LongInt, would then be stored as:

    Base Address+0   Byte3
   Base Address+1   Byte2
   Base Address+2   Byte1
   Base Address+3   Byte0

Motorola processors (those used in Mac's) use "Big Endian" byte order.