# fma

## Name

fma — perform a fused multiply-add operation

## Declaration

 genType fma( genType a, genType b, genType c);

## Parameters

a

Specifies the first multiplicand.

b

Specifies the second multiplicand.

c

Specifies the value to be added to the result.

## Description

fma performs, where possible, a fused multiply-add operation, returning a * b + c. In use cases where the return value is eventually consumed by a variable declared as precise:

• fma() is considered a single operation, whereas the expression a * b + c consumed by a variable declared as precise is considered two operations.

• The precision of fma() can differ from the precision of the expression a * b + c.

• fma() will be computed with the same precision as any other fma() consumed by a precise variable, giving invariant results for the same input values of a, b and c.

Otherwise, in the absense of precise consumption, there are no special constraints on the number of operations or difference in precision between fma() and the expression a * b + c.

## Version Support

fma - -