View source for FP11-E Floating Point Processor

The '''FP11-E Floating Point Processor''' is the optional [[hardware]] [[floating point]] unit for the [[KD11-K CPU]] of the [[PDP-11/60]]. The KD11-K provided the full [[FP11 floating point]] using [[microcode]]; the FP11-E was an option which provided considerably improved floating point performance.

It was a 4 [[DEC card form factor|hex]] board [[co-processor]]:

* Floating Point Next Micro-Address (FNUA - M7878)
* Floating Point Exponent (FLTEXP - M7879)
* Multiplying Network (MULNET - M7880)
* Floating Point ALU (FALU - M7881)

which mounted in slots 8-11 of the [[Central Processing Unit|CPU]]'s [[backplane]]. The main CPU can detect the presence of the FP11-E, and, if present, uses it to perform any floating point [[instruction]]s found in the [[program]].

Electrically, it connected directly to the CPU and is controlled by it; unidirectional data buses are provided to move information (including instructions) from the CPU to the FPP, and vice versa.

The FP11-E has its own microcode, 88 bits wide, to control its operation, and interaction with the main CPU.

{{PDP-11}}

[[Category: PDP-11 Processors]]