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t, :J yJ 1401 DATA PROCESSING SYSTEM BULLETIN
IBM 1401 SYMBOLIC PROGRAMMING SYSTEM: PRELIMINARY SPECIFICATIONS
This bulletin is a minor revision of, but does not supersede, the original edition, form }28-0200. Principal changes
are the addition of information regarding the output accompanying the object program (page 10) and the inclusion
of Control and Execute commands as part of the Processor Control Operations (page 19).
In order to solve a given problem or perform a given function, the IBM 1401 Data
Processing System must execute a logical sequence of instructions known as a program.
To be meaningful, this program must be written in the actual language of the machine.
A program written in this manner is said to be coded in machine language. This method
of coding can be time-consuming and prone to clerical and logical errors. Also a hand
, coded ma.chine language program, which may represent a great deal of programming
effort, is not relocatable; that is, it cannot be executed from a different section of the
processing unit without being manually changed. Another difficulty arises when instructions
are inserted or deleted after a program has been coded. In this case, all instructions
that refer to other instructions must be changed appropriately.
In order to simplify the preparation of a program for the IBM 1401 and to minimize the
shortcomings mentioned above, the 1401 Symbolic Programming System was developed.
Figure 1 is an illustration of a routine written for the 1401. Figure 1a shows the routine
as coded in 1401 symbolic language. Figure 1b illustrates the listing of the same routine
after it has been assembled into the machine language program.
This bulletin is devoted to a description of the preliminary specifications of the 1401
Symbolic Programming System. It also describes, briefly, the basic principles and
concepts of symbolic programming in general. A knowledge of programming in actual
1401 machine language is presupposed. The listing, program deCK and operating
instructions for the symbolic programming processor will be made available at a later
date.
The processor for the 1401 Symbolic Programming System is designed to operate on
configurations of the 1401 Data Processing System equipped with a 1402 Card Read Punch.
@ 1959 and 1960 by International Business Machines Corporation
TABLE OF CONTENTS
Page
Basic Principles and Concepts of Symbolic Programming 3
General Description of the 1401 Symbolic Programming System 5
A. 1401 Symbolic Programming System Coding Sheet 5
B. Organization of Processor 9
Programming the IBM 1401 using the Symbolic Programming System 11
A. Area Definition 11
B. 1401 Symbolic Program Instructions 15
C. Processor Control Operations 19
Ftulctional List of Mnemonic Operation Codes 22
Sample Program 23
IAI OPERAND IBIOPERAND
LINE COUNT LABEL OPERATION
ADDRESS
CHAR.
~ ADDRESS
CHAR. :3 d COMMENTS
ADJ.
27 28 ADJ. ~ 39 40
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