# FP780 Floating-Point Accelerator

From Computer History Wiki

The **FP780 Floating-Point Accelerator** was an optional floating point accelerator for the VAX-11/780's KA780 CPU; the floating point instructions were performed by the microcode when it was not installed. It was installed in slots 24 through 28 of the CPU's backplane.

## Implementation

It was implemented on five hex cards:

Slot | Board | Acronym | Function |
---|---|---|---|

24 | M8285 | FNM | Normalization and fraction division |

25 | M8286 | FMH | Fraction multiplication (most significant bits) |

26 | M8287 | FML | Fraction multiplication (least significant bits) |

27 | M8288 | FAD | Fraction addition and subtraction |

28 | M8289 | FCT | Exponent manipulation and FPA control |

## External links

- FP780 Floating-Point Accelerator Technical Description (EK-FP780-TD-001)