Big Endian

The hexadecimal number 0x1234 will occupy two bytes of memory. Each hexadecimal digit can be 
represented by 4 bits (a nibble). So 0x12 will be stored in one byte and 0x34 will be stored in another 
byte.

A big endian computer would store the number 0x1234 in memory as follows, where A is a pointer to a 
byte in memory.

Starting with the leftmost byte of the number and working towards the right. 0x12 will be stored at A 
and the last byte 0x34 will be stored at A+1. In memory this would look like.

A       A+1 
0x12  0x34 

The same applies for larger numbers. A 32 bit number (4 bytes) 0x12345678 will be stored at address 
A as follows. The leftmost byte 0x12 will be stored at A, the next byte 0x34 at A+1, the next 0x56 and 
A+2 and the last byte 0x78 at A+3.

A       A+1   A+2   A+3
0x12  0x34  0x56  0x78
 

Little Endian

Little endian computers on the other hand use the opposite method to big endian computers. The 
number 0x1234 would be stored at location A as follows.

This time we start with the rightmost byte of the number 0x34 and place this at address A. The next 
byte (working left) 0x12 is then placed at A+1.

A       A+1
0x34  0x12

It has the same byte ordering as a big endian computer storing the number 0x3412.

The number 0x12345678 will be stored as the number 0x78563412 on a big endian computer. So the 
rightmost byte 0x78 is stored at A, the next byte 0x56 is stored at A+1, the next byte 0x34 is stored at 
A+2 and the last byte 0x12 is stored at A+3.
 

A       A+1   A+2  A+3
0x78  0x56  0x34  0x12

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