Mary Payne designed the VAX floating point POLY instruction at DEC.
But the microcode and hardware floating point implementations did it slightly differently. Then the MicroVAX dropped it, then picked it up again but wrong, then fixed it, then lost it again.
>The Digital Equipment Corporation (DEC) VAX's POLY instruction is used for evaluating polynomials with Horner's rule using a succession of multiply and add steps. Instruction descriptions do not specify whether the multiply and add are performed using a single FMA step. This instruction has been a part of the VAX instruction set since its original 11/780 implementation in 1977.
But the microcode and hardware floating point implementations did it slightly differently. Then the MicroVAX dropped it, then picked it up again but wrong, then fixed it, then lost it again.
http://simh.trailing-edge.com/docs/vax_poly.pdf
https://documentation.help/VAX11/op_POLY.htm
https://en.wikipedia.org/wiki/Multiply%E2%80%93accumulate_op...
>Multiply–accumulate operation
>The Digital Equipment Corporation (DEC) VAX's POLY instruction is used for evaluating polynomials with Horner's rule using a succession of multiply and add steps. Instruction descriptions do not specify whether the multiply and add are performed using a single FMA step. This instruction has been a part of the VAX instruction set since its original 11/780 implementation in 1977.
https://news.ycombinator.com/item?id=20558618
>VAX was a crazy town ISA too, with stuff like single isntruction polynomial evaluation.