fma
Returns the double-precision fused multiply-addition of a * b + c.
| ret fma(double a, b, c); |
|---|
Parameters
-
a
-
[in] The first value in the fused multiply-addition.
-
b
-
[in] The second value in the fused multiply-addition.
-
c
-
[in] The third value in the fused multiply-addition.
Return Value
The double-precision fused multiply-addition of parameters a * b + c. The returned value must be accurate to 0.5 units of least precision (ULP).
Remarks
The fma intrinsic must support NaNs, INFs, and Denorms.
To use the fma intrinsic in your shader code, call the ID3D11Device::CheckFeatureSupport method with D3D11_FEATURE_D3D11_OPTIONS to verify that the Direct3D device supports the ExtendedDoublesShaderInstructions feature option. The fma intrinsic requires a WDDM 1.2 display driver, and all WDDM 1.2 display drivers must support fma. If your app creates a rendering device with feature level 11.0 or 11.1 and the compilation target is shader model 5 or later, the HLSL source code can use the fma intrinsic.
Type Description
| Name | Template Type | Component Type | Size |
|---|---|---|---|
| a | scalar, vector, or matrix | double | any |
| b | same as input a | double | same dimensions as input a |
| c | same as input a | double | same dimensions as input a |
| ret | same as input a | double | same dimensions as input a |
Minimum Shader Model
This function is supported in the following shader models.
| Shader Model | Supported |
|---|---|
| Shader model 5 or later | yes |
Requirements
| Requirement | Value |
|---|---|
| Minimum supported client |
Windows 8 [desktop apps | UWP apps] |
| Minimum supported server |
Windows Server 2012 [desktop apps | UWP apps] |
| Header |
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