Difference between revisions of "KE11-A Extended Arithmetic Element"

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The '''KE11-A Extended Arithmetic Element''' is an autonomous [[UNIBUS]] [[peripheral]] which can perform a variety of arithmetic or logical operations:
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The '''KE11-A Extended Arithmetic Element''' is an [[Extended Arithmetic Element]] implemented as autonomous [[UNIBUS]] [[peripheral]]; it can perform a variety of arithmetic or logical [[operator|operations]]:
  
 
* multiplication
 
* multiplication
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(The last is used for implementation of [[floating point]] in [[software]].)
 
(The last is used for implementation of [[floating point]] in [[software]].)
  
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It is implemented as several [[DEC card form factor|quad]] and dual [[printed circuit board|boards]], plugged into a custom four-slot [[system unit]] (details below).
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It is implemented as several [[DEC card form factor|quad]] and dual [[printed circuit board|boards]], plugged into a custom four-slot [[system unit]] [[backplane]] (details below).
  
 
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 [[Central Processing Unit|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 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 [[Central Processing Unit|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.
  
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The KE11-A can be operated with an optional [[KM11-A Maintenance Set]] in order to diagnose faults.
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The KE11-A can be operated with an optional [[KM11-A Maintenance Set]] (plugged into [[DEC edge connector contact identification|slot B02]]) in order to diagnose faults.
  
 
It was replaced by the [[KE11-B Extended Arithmetic Element]], a [[program compatible]] re-implementation on a single hex card.
 
It was replaced by the [[KE11-B Extended Arithmetic Element]], a [[program compatible]] re-implementation on a single hex card.
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 +
==Registers==
 +
 +
The device has a number of [[register]]s, which can be configured to sequential locations in the I/O page; most are [[word]]s, but there are two [[byte]] registers. It is normally configured to [[address]]es 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).
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{| border=1
 +
! Register !! Abbreviation !! Address || Size
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|-
 +
|'''Divide''' || '''DIV''' || 777300 || W
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|-
 +
|Accumulator || AC || 777302 || W
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|-
 +
|Multiplier-Quotient || MQ ||777304 || W
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|-
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|'''Multiply''' || '''MUL''' || 777306 || W
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|-
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|''Step Counter''$ || ''SC'' || 777310 || B
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|-
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|''Status Register''% || ''SR'' || 777311 || B
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|-
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|Normalize || NOR || 777312 || W
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|-
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|'''Logical Shift''' || '''LSH''' || 777314 || W
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|-
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|'''Arithmetic Shift''' || '''ASH''' || 777316 || W
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|}
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 +
$ The SC is read-only as an individual byte, but can written as a word together with the SR.<br>
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% The SR is read-only as an individual byte, but can written as a word together with the SC.
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 +
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).                           
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===Status Register (SR)===
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{{8bit-header}}
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| Overflow XOR Negative || Negative || AC = -1 || AC = 0 || MQ = 0 || AC = MQ = 0 || AC = MQ15 || Carry
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{{8bit-bitout}}
  
 
==Hardware==
 
==Hardware==
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* M827 Clock and States
 
* M827 Clock and States
  
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and a pair of M234 Register dual-height boards, plugged into the quad custom [[backplane]].
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and a pair of M234 Register dual-height boards, plugged into the quad custom backplane.
  
 
===Board locations===
 
===Board locations===
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|}
 
|}
  
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{{PDP-11s}}
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==See also==
 +
 
 +
* [[KE11-B Extended Arithmetic Element]]
 +
 
 +
==Further reading==
 +
 
 +
* ''KE11-A User's Guide'' (EK-KE11A-OP ?)
 +
* ''KE11-A Technical Manual'' (EK-KE11A-TM ?)
 +
 
 +
==External links==
 +
 
 +
* [http://www.bitsavers.org/pdf/dec/pdp11/handbooks/PDP1120_Handbook_1972.pdf pdp11/20-15-r20 processor handbook] - the operation of the KE11-A is covered in Chapter 8 (pp. 155-162 of the PDF)
 +
* [http://bitsavers.org/pdf/dec/pdp11/1120/KE11-A_ExtendedArithElem.pdf KE11-A extended arithmetic element] (DEC-11-HKEA-D)
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* [http://www.bitsavers.org/pdf/dec/unibus/KE11-A__Extended_Arithmetic_Element_Engineering_Drawings__Nov71.pdf KE11-A extended arithmetic element engineering drawings]
  
 
[[Category: PDP-11s]]
 
[[Category: PDP-11s]]
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[[Category: UNIBUS]]

Latest revision as of 20:17, 2 July 2023

The KE11-A Extended Arithmetic Element is an Extended Arithmetic Element implemented as autonomous UNIBUS peripheral; it can perform a variety of arithmetic or logical operations:

  • multiplication
  • division
  • multi-bit shifts

(The last is used for implementation of floating point in software.)

It is implemented as several quad and dual boards, plugged into a custom four-slot system unit backplane (details below).

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 (plugged into slot B02) in order to diagnose faults.

It was replaced by the KE11-B Extended Arithmetic Element, a program compatible re-implementation on a single hex card.

Registers

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).

Register Abbreviation Address Size
Divide DIV 777300 W
Accumulator AC 777302 W
Multiplier-Quotient MQ 777304 W
Multiply MUL 777306 W
Step Counter$ SC 777310 B
Status Register% SR 777311 B
Normalize NOR 777312 W
Logical Shift LSH 777314 W
Arithmetic Shift ASH 777316 W

$ 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
07 06 05 04 03 02 01 00

Hardware

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.

Board locations

These are the board locations for the KE11-A (as seen from the board side of the backplane):

Connector
Slot A B C D E F
1 UNIBUS In M7210 Data Control
2 Unused KM11-A M234 Register
(low byte) 		M234 Register
(high byte)
3 G772
Power 		Reserved M7211 Register Control
4 UNIBUS Out M827 Clock & States

See also

Further reading

  • KE11-A User's Guide (EK-KE11A-OP ?)
  • KE11-A Technical Manual (EK-KE11A-TM ?)

External links

Retrieved from "https://gunkies.org/w/index.php?title=KE11-A_Extended_Arithmetic_Element&oldid=30259"