Double Word

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According to Intel's definition of a x86 16-bit Word, a Double Word refers a 32-bit entity, while IBM 360 and successors with 32-bit words have double words with 64-bit.

=Integer and long= Even in x86-64, double words are still considered as default word size. x86 and and x86-64 C-Compiler use double words as signed and unsigned integers, Java integers as well. Microsoft 64 bit compiler long is a 32-bit Double word as well, while with 64-bit GCC uses 64-bit Quad Words as longs.

typedef unsigned int DWORD;

=Ranges=

=Alignment= Double Words stored in memory should be stored at byte addresses divisible by four. Otherwise at runtime it will cause a miss-alignment exception on some processors, or a huge penalty on others.

=Endianness= Main article: Endianness.

Litte-endian Layout
The little-endian memory layout, as typical for Intel x86 cpus. For instance the double word integer 16909060 or 0x01020304:

Big-endian Layout
The big-endian memory layout, as typical for Motorola cpus. For instance the double word integer 16909060 or 0x01020304:

=See also=
 * Piece-Sets
 * Byte
 * Word
 * Quad Word

=External Links=
 * Dword, Qword, and Oword from Wikipedia
 * Byte from Wikipedia
 * Endianness from Wikipedia
 * Understanding Big and Little Endian Byte Order
 * DAV's Endian FAQ - ON HOLY WARS AND A PLEA FOR PEACE by Danny Cohen

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