Developer Guide and Reference

Contents

_xgetbv()

Reads the content of an extended control register.

Syntax

extern unsigned __int64 _xgetbv(unsigned int xcr);
Arguments
xcr
An extended control register to be read. Currently, only the value '
0
' is allowed.
Description
This intrinsic reads from extended control registers. Currently, the only control register allowed/defined is
(XCR0) XFEATURE_ENABLED_MASK
register. The corresponding constant is defined in the
immintrin.h
file to refer to this register:
#define _XCR_XFEATURE_ENABLED_MASK 0
This intrinsic maps to
XGETBV
instruction.
Returns
Returns the content of a specified extended control register.

Product and Performance Information

1

Intel's compilers may or may not optimize to the same degree for non-Intel microprocessors for optimizations that are not unique to Intel microprocessors. These optimizations include SSE2, SSE3, and SSSE3 instruction sets and other optimizations. Intel does not guarantee the availability, functionality, or effectiveness of any optimization on microprocessors not manufactured by Intel. Microprocessor-dependent optimizations in this product are intended for use with Intel microprocessors. Certain optimizations not specific to Intel microarchitecture are reserved for Intel microprocessors. Please refer to the applicable product User and Reference Guides for more information regarding the specific instruction sets covered by this notice.

Notice revision #20110804