Third Edition
November 1969

[handwritten: Amended 5.7.71]


§1 Introduction

§2 The Titan Computer

2.1 General description
2.2 The main store
2.3 Storage of information on Titan
2.4 Instructions in the machine
2.5 Written form of instructions

§3 B orders and Test Orders

3.1 General
3.2 General pupose B registers
3.3 B arithmetic
3.4 Notation
3.5 Arithmetic operations
3.6 Logical operations
3.7 Shifts
3.8 Jump orders
3.9 Test instructions
3.10 The B test register
3.11 B carry
3.12 Special purpose B registers

§4 The Accumulator Orders

4.1 Floating point numbers
4.2 The accumulator
4.3 Rounding
4.4 Fixed point arithmetic
4.5 Overflow
4.6 Simple floating point instructions
4.7 Simple fixed point instructions
4.8 Further fixed point instructions
4.9 Unrounded floating point working
4.10 Pseudo double length working
4.11 Load and store instructions
4.12 Fixed point division

§5 Extracode Instructions

5.1 Introduction
5.2 The interpretation of an extracode instruction
5.3 The accumulator extracodes
5.4 B register arithmetic
5.5 Subroutine entry

§6 Input and Output

6.1 Introduction
6.2 Documents and streams
6.3 Internal code
6.4 Characters and records
6.5 Input and output transfer extracodes
6.6 Binary input and output
6.7 Status extracodes
6.8 Magnetic tape streams
6.9 Pending streams
6.10 Input and output organisational extracodes
6.11 Limout
6.12 Output limit
6.13 Stream failures
6.14 The structure of streams

§7 Backing Store Devices

7.1 General description
7.2 Basic transfer operations
7.3 Organisational extracodes
7.4 Direct faults
7.5 Delayed faults
7.6 Detailed description of hardware
7.7 Interlocks
7.8 Efficient use of BSDs

§8 Intermediate Input Language (IIT)

8.1 Introduction
8.2 Parameters
8.3 Expressions
8.4 Parameter setting and unsetting
8.6 Start directive
8.7 Line Imaging
8.8 The parameters of row 0
8.9 The K directive
8.10 The F directive
8.11 Post mortem directives
8.12 Ignorable sections
8.13 Entry conditions
8.14 Input streams
8.15 Errors

§9 Faults, Monitor and Trapping

9.1 Faults
9.2 System monitor
9.3 Private monitor
9.4 Trapping
9.5 Direct fault trap routines
9.6 Delayed fault trap routines
9.7 Causing faults
9.8 Direct fault numbers
9.9 Post mortems
9.10 Dump option
9.11 Monitor output streams

§10 The Titan Operating System

10.1 Introduction
10.2 Input and output peripherals
10.3 Format of input documents
10.4 The job description
10.5 The program log
10.6 Other facilities of the operating system

§11 General Organisational Extracodes

11.1 Phase change and store control
11.2 Job control
11.3 Date and time extracodes
11.4 Peripheral computer control


A Internal code tables

A1 Available codes
A2 Internal code characters
A3 Warning sequences
A4 Line printer equivalent characters
A5 Teletype consoles

B Summary of extracodes

C Notation

D System fault numbers

E Basic instruction codes

F System commands


This manual gives full details of the machine-code programming system for Titan. It is intended as a reference manual for experienced programmers and is in no sense a beginner's manual. It therefore contains only a description of the facilities available, with little or no attempt to indicate how they can be used in programs.

The manual describes the Titan programming system as it is at present. The Supervisor is continually evolving, and therefore it will be necessary to amend the information given here from time to time.

It would be appreciated if notice of any errors or omissions, or suggestions for better presentation of the material, could be given to the Superintendent of Computing Services.

Copyright © 1965-1971 University of Cambridge Computer Laboratory. Distributed by permission. Thanks to Barry Landy, Roger Needham and David Hartley for giving permission to distribute these documents. Thanks to Barry Landy for lending me the paper document from which this was scanned. Any typographical errors probably arose in the course of OCR.

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