Digital Equipment Corporation 220240 Instruction Manual

THE INFORMATION DISTRIBUTOR distributes information from the Internal Processor to all output devices. Only the output device se- lecte

from the Light Pen, the computer carries out previously programmed instructions. Requires Real-Time Option. THE 18-BIT RELAY BUFFER, TY

ARITHMETIC AND CONTROL ELEMENT In this chapter the described in detail. plained and listed. functions of the Arithmetic and Control El

ACCUMULATOR (AC): Arithmetic operations are performed in this 18-bit register. The AC may be cleared and complemented. Its con- tents

MEMORY The memory contains stored information for processing, and the instruc- tions of the program being run. Memory capacities of fr

POWER SINGLE STEP SINGLE INSTRUCTION REPEAT SPEED Console Switches Function ADDRESS A group of 13 switches which establishes the memory a

EXAMINE EXAMINE NEXT DEPOSIT Console Key START Function Starts the processor. The first instruction is taken from memory cell specified b

and the instruction part (bits O-4) of this word are placed in the IR. The C(PC) are then incremented by one. If a two-cycle ins

01 1121314151617 ~8~9~10~11~12~13~14~15~16~17 vvt1 Operation Indirect Operand Address Code Address (Defer) Figure 5 - Memory reference instr

Since bit 0 of a word is used for the sign of a number, the largest positive number that can be represented is 217-l. If, in l’s comp

OCTAL MNEMONIC CODE TIME SYMBOL (BITS O-3) (b-c) OPERATION tad Y 34 16 Two’s complement Add. The C(Y) are added to the C(AC) in 2’s com

OCTAL MNEMONIC CODE TIME SYMBOL (BITS O-3) (ec) OPERATION is2 Y 44 16 Index and Skip if Zero. The C(Y) are in- cremented by one in

OPERATE CLASS The instructions of the Operate class require one cycle for their execution. The octal code (bits O-3) for this class

MNEMONIC OCTAL EVENT SYMBOL CODE TIME OPERATION ral rtl 740010 3 Rotate AC Left. The C(AC) and the C(L) are rotated left one place. C(AC

MNEMONIC OCTAL EVENT SYMBOL CODE TIME OPERATION snl 740400 1 Skip if Non-zero Link. If C(L) is 1, the next instruction is skipped. I

Operation Sub-Device Device Sob-Device Code Selection Selection Selection ,&$qfyhJl 0 1 2 3 4 5 6 7 8 9 10 11 12 13114115116[17 C

CHAPTER 3 INPUT-OUTPUT EQUIPMENT FUNCTIONS AND PROGRAMMING PDP-4 is capable of operating with the ten input-output devices described in Ch

(b) Transfers data from the information buffer of an input device to the AC, through the Information Collector (c) Transfers informat

DISTRIBUTOR From IO Device Flags Requests (11) 4 INTERRUPT !&I& oirection INTERRUPT DATA - INTERRUPT 18 Addreas ADDRESS Data ) Request

INFORMATION DISTRIBUTOR (ID) The Information Distributor presents the static data contained in the AC to each output device requiring

Foreword This manual is for programmers and users of the Programmed Data Processor-4, a high speed, stored program, digital computer

INPUT- OUTPUT STATUS INSTRUCTION The iors (in-out read status) instruction, 700314, enables the status of all IO devices to be read

Input-Output Devices All of the Input-Output Devices discussed below can be controlled by the Real-Time Option, Type 25. The Real-Tim

The CRT, Type 30A is selected when the numbers 0 and 5 (octal) are speci- fied in bits 8 and 9 respectively, of the iot instruction. T

LIGHT PEN, TYPE 32 The Light Pen is a photosensitive device which detects the presence of information displayed on a CRT. If the L

The instructions are: dsf - 700501 - Skip if the Display flag is a 1. The Display Flag is set to 1 when the Light Pen senses

The Display flag is connected to the Program Interrupt and to bit 5 of the iors instruction. The co-ordinates of the corners are:

(8) Information cl 10s q PIG 8 BIT Analog ANALOG 4 Input TO- DIGITAL CONVERTER Figure 13 - High-speed analog-to-digital converter programming

skips if the conversion is complete; i.e., the converter flag is a 1. The program instructions, iot series 11, are: asf - 701101

MB?, (Alphanumeric) (18)RBIlnformationj m*kip) 1 , Reader Flag 1 PERFORATED- TAPE READER CONTROL Feed Hole 8 Holes of Information * Run Sign

An alphanumeric character is one line (5, 7, or 8 holes) on tape. A binary word consists of three consecutive characters (18 bits) on t

Table Of Contents CHAPTER 1: SYSTEM DESCRIPTION . . . . .._.._._...__..._._... Page 5 CHAPTER 2: ARITHMETIC AND CONTROL ELEMENT ...

The signals to and from the KSR to the control logic are standard serial, 7.5-unit-code Teletype signals. The signals are: start (1

KEYBOARD CONTROL To Printer - Status Bit: 03 Keyboard Flag Interrupt: Keyboard Flag Figure 19 - Keyboard programming logic The Keyboard fla

the Teleprinter flag. The Flag is connected to the Program Interrupt and to bit 4 of the iors instruction. The printing rate is ten cha

/wait for previously printed character completion, then print tsf /wait loop until previous character printed jmp.-1 /return to wait l

psf - 700201 - Skip if the Punch flag is a 1. pcf - 700202 - Clear the Punch flag. pls - 700206 - Load a character into PB h

PERFORATED TAPE PUNCH CONTROL 8 Info. Feed + Advance * TELETYPE BRPE Punch * TAPE Timing Signal PUNCH * Figure 23 - Perforated-Tape Punch pro

instruction transfers the lower six rows (4, 5, 6, 7, 8, and 9). The mode is specified with the Card Read Select instruction. The

The Card Read Flag is connected to the Program Interrupt Control and to bit 9 of the iors instruction. The Card Read Done status l

next row. A flag indicates that the buffer is ready to load. The commands for the Card Punch Control, iot series 64, are: cpsf -

Status Bits: 13-Row Flag M-Card Not OK Interrupt: Row Flag Figure 27 - Card Punch programming logic PROGRAM SEQUENCE /sequence to punch

Typical PDP-4 System

punloc, rowct, grpct, templ, temp2, is2 temp2 jmp loop2 lsz templ jmp loop1 hlt 100-l -14+1 -5+1 0 0 /test for 12 rows /end punching 1 card

A complete line, or 120 columns of information, is placed in the printing buffer. Six bits specify each character (the codes are given

PROGRAM SEQUENCE /sequence to print a line of 120 columns. Output stored 3 /characters per word. /Data begins In register 2000. Seque

CHAPTER 4 THE INTERFACE ELECTRICAL CHARACTERISTICS As explained in previous sections, the standard Interface contains the Real-Time Conne

Common IOT 1 Common IOT 2 Common IOT 3 Figure 29.Typical Pulse Amplifier, Type 4605, used in PDP-4 Device Selector. Example shown is

INFORMATION COLLECTOR (LOCATION 2H8-25) The information collecting sequence begins with an iot pulse from the Device Selector applied

INPUT-OUTPUT SKIP FACILITY (LOCATION 2H06) There are 8 inputs to Input-Output Skip. The iot pulses from the Device Selector strobe a

c/UN I KUL Signals Data lntwrupt Request I I 3.6 &c 3.5 J&c Minimum Maximum Acknowledgment Time To Avoid Time Another Interrupt Address

MNEMONIC CODE cal Y OCTAL TIME CODE (b-3 00 16 dac Y 04 16 jms Y 10 16 dzm Y 14 16 lac Y 20 16 xor Y 24 16 add Y 30 16 tad Y 34 16

OPERATE INSTRUCTIONS MNEMONIC CODE wr nw cma cml oas OCTAL EVENT CODE TIME 740000 - 740000 - 740001 3 740002 3 740004 3 las 750004 ral 740010 rcl 74

CHAPTER 1 SYSTEM DESCRIPTION Summary The Digital Equipment Corporation Programmed Data Processor-4 (PDP-4) is designed to be the control

MNEMONIC CODE OCTAL CODE BASIC IOT INSTRUCTIONS OPERATION iof ion 700002 turn off interrupt 700042 turn on interrupt iors 700314 read status o

BASIC IOT INSTRUCTIONS MNEMONIC CODE OCTAL CODE mci 70700 1 mrs 707012 mli 707005 msc 707101 msi 707201 msf 707301 mrl 707112 mrm 707202 mrr 707

a A b B c c d D e E f F g G h H i I k J k K I L mM n N 0 0 P p 2 s s t T u u v v WW x x Y y z z O--t 1 ” 2 ’ 3- 42 5 v 6A 7

TELETYPE CODE Low order bits 000 001 010 011 100 101 110 111 T 5 car ret 09 space H# N , M. letters 37 A c” D E F G H I J K L M N 0 ii S T U V w

CARD READER CODE A 61 B 62 C D E-z E 65 F 66 G 67 H I 57 J 41 K 42 L 43 M 44 E 44; ; :?I SR ;: _ T u z V 2’5 W 26 X 27 Y Z 337 0 :

LINE PRINTER CODE A 61 B 62 C 63 D 64 E 65 F 66 G 67 H 70 I 71 J 41 K 42 L 43 M 44 N 45 0 46 P 47 Q 50 R 51 s 22 T 23 U 24 V 25

APPENDIX 3 Read-h Mode Sequence The initial data input to PDP-4 is made using the keys and switches on the Operator Console. A small pr

BLOCK FORMAT LOADER The block format loader will read a block format binary tape of the following format: dac A A is the address o

APPENDIX 4 PDP-4 Assembly Program The more important characteristics of the PDP-4 Assembly Program are mentioned briefly here to provid

SYLLABLES: A syllable can take several forms. It can be a value symbol, a period ( . ), a flexowriter input pseudo-instruction (flex o

ARITHMETIC ------mm -w-----m-- IMTERFACE *Included in B Standard PDP-4 Figure 1 - PDP-4 System with Real-Time Connection ARITHMETIC AND CO

PSEUDO INSTRUCTIONS FLEXOWRITER INPUT PSEUDO INSTRUCTIONS: The pseudo-instruction, flex A& causes the (six-bit) FIO-DEC codes for the t

APPENDIX 5 Multiply and Divide Subroutines MULTIPLY SUBROUTINE /PDP-4 ones complement single precision multiplication subroutine /calling

DIVIDE SUBROUTINE /PDP-4 ones complement divide subroutine /calling sequence: /lac high order dividend /jms divide /lac low order divide

DIVIDE SUBROUTINE (continued) dv2, lac quo ral dac quo isz dvl imp dv3 lac dv5 ral lac dvd spl cma dac dvd iac dv4 ral lac quo spl cma +

APPENDIX 6 Programming Aids The following programming aids are supplied with the PDP-4. PDP-4 ASSEMBLY PROGRAM -A one-pass assembler wh

OCTAL DEBUG -A simple debugging routine. MISCELLANEOUS INPUT-OUTPUT ROUTINES-Octal, decimal, double precision input and output and specia

APPENDIX 7 Powers Of Two 2" 2 4 8 16 32 64 128 256 512 1 024 2 048 4 096 8 192 16 384 32 768 65 536 131 072 262 144 524 288 I 048

DIGITAL EQUIPMENT CORPORATION . MAYNARD, MASSACHUSETTS F-45 Printed in U.S.A. 2Rl--10,/6X

Keyboard and Control, Type 65. The Real-Time Option, Type 25 gives the system the additional capability to operate efficiently over

. The Perforated-Tape Reader (top) and Printer-Keyboard (bottom). 8