log2

Returns the base-2 logarithm of the specified value.

ret log2(x)

Parameters

Item	Description
x	[in] The specified value.

Return Value

The base-2 logarithm of the x parameter. If the x parameter is negative, this function returns indefinite. If the x parameter is 0, this function returns +INF.

Type Description

Name	Template Type	Component Type	Size
x	scalar, vector, or matrix	float	any
ret	same as input x	float	same dimension(s) as input x

Minimum Shader Model

This function is supported in the following shader models.

Shader Model	Supported
Shader Model 2 (DirectX HLSL) and higher shader models	yes
Shader Model 1 (DirectX HLSL)	yes (vs_1_1 only)

Requirements

Requirement	Value
Header	Corecrt_math.h

See also

Intrinsic Functions (DirectX HLSL)