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countbits (sm5 - asm)

  • Article

Counts the number of bits set in a number.

countbits dest[.mask], src0[.swizzle]
Item Description
dest
 [in] The address of the results.
src0
 [in] The input 32-bit number.

Remarks

This instruction can be used to compute shader input coverage percentage.

This instruction applies to the following shader stages:

Vertex Hull Domain Geometry Pixel Compute
X X X X X X

Minimum Shader Model

This instruction is supported in the following shader models:

Shader Model Supported
Shader Model 5 yes
Shader Model 4.1 no
Shader Model 4 no
Shader Model 3 (DirectX HLSL) no
Shader Model 2 (DirectX HLSL) no
Shader Model 1 (DirectX HLSL) no

Shader Model 5 Assembly (DirectX HLSL)