Multiply-subtracts scalar single-precision floating-point values using three float32vectors. The corresponding FMA instruction is VFMSUB<XXX>SS, where XXX could be 132, 213, or 231.
a |
float32 vector used for the operation |
b |
float32 vector also used for the operation |
c |
float32 vector also used for the operation |
Performs a set of SIMD multiply-subtract computation on scalar single-precision floating-point values using three source vectors/operands, a, b, and c. Corresponding values in two operands, a and b, are multiplied and the infinite precision intermediate results are obtained. From the infinite precision intermediate results, the values in the third operand, c, are subtracted. The final results are rounded to the nearest float32 values.
The compiler defaults to using the VFMSUB213SS instruction and uses the other forms VFMSUB132SS or VFMSUB231SS only if a low level optimization decides it is useful/necessary. For example, the compiler could change the default if it finds that another instruction form saves a register or eliminates a move.
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