_mm_fnmsub_ps, _mm256_fnmsub_ps

Multiply-subtracts negated packed single-precision floating-point values of three float32 vectors. The corresponding FMA instruction is VFNMSUB<XXX>PS, where XXX could be 132, 213, or 231.


For 128-bit vector

extern __m128 _mm_fnmsub_ps(__m128 a, __m128 b, __m128 c);

For 256-bit vector

extern __m256 _mm256_fnmsub_ps(__m256 a, __m256 b, __m256 c);



float32 vector used for the operation


float32 vector also used for the operation


float32 vector also used for the operation


Performs a set of SIMD negated multiply-subtract computation on packed 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 negated infinite precision intermediate result is obtained. From this intermediate result the value in the third operand, c, is subtracted, after which the final results are rounded to the nearest float32 values.

The compiler defaults to using the VFNMSUB213PS instruction and uses the other forms VFNMSUB132PS or VFNMSUB231PS only if a low level optimization decides it is useful or necessary. For example, the compiler could change the default if it finds that another instruction form saves a register or eliminates a move.


Result of the negated multiply-subtract operation.

Para obtener información más completa sobre las optimizaciones del compilador, consulte nuestro Aviso de optimización.