Intel x86 - Hacker's Compendium

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Intel x86

Description

The x86 architecture as defined by Intel.

Macros

Type	Macro	Format	Description
Identification	`i386` `__i386` `__i386__`		Defined by GNU C
Version	`__i386__` `__i486__` `__i586__` `__i686__`		Defined by GNU C
Identification	`__i386`		Defined by Sun Studio
Identification	`__i386` `__IA32__`		Defined by Stratus VOS C
Identification	`_M_I86`		Only defined for 16-bits architectures Defined by Visual Studio, Digital Mars, and Watcom C/C++ (see note below)
Identification	`_M_IX86`		Only defined for 32-bits architectures Defined by Visual Studio, Intel C/C++, Digital Mars, and Watcom C/C++
Version	`_M_IX86`	V`00`	V = Version
Identification	`__X86__`		Defined by Watcom C/C++
Identification	`_X86_`		Defined by MinGW32
Identification	`__THW_INTEL__`		Defined by XL C/C++
Identification	`__I86__`		Defined by Digital Mars
Version	`__I86__`	V	V = Version
Identification	`__INTEL__`		Defined by CodeWarrior
Identification	`__386`		Defined by Diab

Examples

CPU	`_M_IX86`	`__I86__`
80386	300	3
80486	400	4
Pentium	500	5
Pentium Pro/II	600	6

Notes

Notice that Watcom C/C++ defines _M_IX86 for both 16-bits and 32-bits architectures. Use __386__ or _M_I386 to detect 32-bits architectures in this case.

Notice that the Stratus VOS is big-endian on IA32, so these macros cannot be used to detect endianness if __VOS__ is set.