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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 |