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.

code format="cpp" typedef unsigned int DWORD; code

=Ranges=
 * ~ type ||~ language ||~ min ||~ max ||
 * unsigned int || C, C++ ||> 0 ||> 4,294,967,295 ||
 * hexadecimal ||  ||> 0x00000000 || 0xFFFFFFFF ||
 * int || C, C++, Java ||> -2,147,483,648 ||> 2,147,483,647 ||
 * hexadecimal ||  ||> 0x80000000 || 0x7FFFFFFF ||

=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:
 * ~ Address ||~ Byte ||~ Significance ||
 * 0x0000 || 0x04 ||= LS Byte ||
 * 0x0001 || 0x03 ||=  ||
 * 0x0002 || 0x02 ||=  ||
 * 0x0003 || 0x01 ||= MS Byte ||

Big-endian layout
The big-endian memory layout, as typical for Motorola cpus. For instance the double word integer 16909060 or 0x01020304:
 * ~ Address ||~ Byte ||~ Significance ||
 * 0x0000 || 0x01 || MS Byte ||
 * 0x0001 || 0x02 ||  ||
 * 0x0002 || 0x03 ||  ||
 * 0x0003 || 0x04 || LS Byte ||

=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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