Intel® C++ Compiler Classic Developer Guide and Reference

ID 767249
Date 3/31/2023
Public

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Document Table of Contents

_xsetbv()

Writes the given value to a specified extended control register.

Syntax

extern void _xsetbv(unsigned int xcr, unsigned __int64 val);

Arguments

xcr

An extended control register to be written. Currently, only the value '0' is allowed.

val

Value to be written to the specified extended control register.

Description

This intrinsic writes the given value to the specified extended control register. 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 XSETBV instruction.