FP11 floating point

From Computer History Wiki
Revision as of 04:17, 18 September 2016 by Jnc (talk | contribs) (a start, somewhat stubby)
(diff) ← Older revision | Latest revision (diff) | Newer revision → (diff)
Jump to: navigation, search

FP11 floating point is the term used for the floating point data types and instructions supported by most PDP-11s which had hardware support for floating point. (Some supported a simpler, less capable floating point capability.)

It supported short (32 bit) and long (64 bit) floating point numbers; both forms used an 8 bit exponent (in 'excess 0200' notation, giving an exponent range of +127. to -128.), a sign bit, and the remaining bits were the fractional part.

The initial implementation was the FP11-B Floating-Point Processor for the KB11-A CPU for the PDP-11/45; it was later used in the KB11-B CPU of the PDP-11/70. Later implementations included: