LITTLE_ENDIAN and BIG_ENDIAN

The keywords LITTLE_ENDIAN and BIG_ENDIAN could specify store order in memory.

If there is a two byte data in memory, Ex: long d=0x12345678

It would be store as the order as below table.

	big-endian	little-endian
0x0000	0x12	0x78
0x0001	0x34	0x56
0x0002	0x56	0x34
0x0003	0x78	0x12

What different ?

for some CPU：

• INTEL X86、DEC VAX use LITTLE-ENDIAN
• HP、IBM、MOTOROLA 68K use BIG-ENDIAN
• POWERPC support both，called BI-ENDIAN