KE11-A Extended Arithmetic Element
- multi-bit shifts
- logical shift
- arithmetic shift
The KE11-A was originally produced for use with the PDP-11/20, whose KA11 CPU did not have multiply, divide, or multi-bit shift operations. As a UNIBUS peripheral, not integrated into the CPU, it was also usable with other models, e.g. the PDP-11/05 and PDP-11/04, which likewise did not implement multiplication in hardware, etc.
The KE11-A can be operated with an optional KM11-A Maintenance Set in order to diagnose faults.
The device has a number of registers, which can be configured to sequential locations in the I/O page; most are words, but there are two byte registers. It is normally configured to addresses 777300-777316; a second KE11-A, if present, is configured to addresses 777320-777336. The operation to be performed is selected by the register which data is written to. Registers which hold results are readable, but many of the operation selection registers are write-only. In the register table (below), those which are read/write are shown in normal font; those which are read-only are in italics; those which are write-only in bold (these return '0' when read).
$ The SC is read-only as an individual byte, but can written as a word together with the SR.
% The SR is read-only as an individual byte, but can written as a word together with the SC.
Division takes as one operand a 32-bit value held in the AC (high order) and MQ (low order); a remainder is left in the AC. Multiplication produces a 32-bit product in the AC (high order) and MQ (low order). Both arithmetic and logical shifts operate on a 32-bit value held in the AC (high order) and MQ (low order).
Status Register (SR)
|Overflow XOR Negative||Negative||AC = -1||AC = 0||MQ = 0||AC = MQ = 0||AC = MQ15||Carry|
The KE11-A consists of 3 quad boards:
- M7210 Data Control
- M7211 Register Control
- M827 Clock and States
and a pair of M234 Register dual-height boards, plugged into the quad custom backplane.
These are the board locations for the KE11-A (as seen from the board side of the backplane):
|1||UNIBUS In||M7210 Data Control|
|2||Unused||KM11-A|| M234 Register
| M234 Register|
|Reserved||M7211 Register Control|
|4||UNIBUS Out||M827 Clock & States|
|v • d • e PDP-11 Computers and Peripherals|
| UNIBUS PDP-11s - PDP-11/20 • PDP-11/15 • PDP-11/35 • PDP-11/40 • PDP-11/45 • PDP-11/50 • PDP-11/55 • PDP-11/70 • PDP-11/05 • PDP-11/10 • PDP-11/34 • PDP-11/04 • PDP-11/44 • PDP-11/60 • PDP-11/24 • PDP-11/84 • PDP-11/94
Clones: CM 1420