Sigma XDS 5 User manual

Scientific Data Systems
A XEROX COMPANY
X1ClS SIGMA 5/7 FLAG
Reference Manual

FLAG
REFERENCE MANUAL
for
XDS SIGMA 5/7 COMPUTERS
PRELIMINARY EDITION
90 16 54A
September 1969
Pri
ce: $4. 00
Xerox Data Systems/701 South Aviation Boulevard/EI Segundo, California 90245
© 1969, Xerox Data Systems, Inc. Printed in U.S.A.

ACKNOWLEDGMENT
The FLAG (Fortran Load And Go) Compiler was developed by Norman Wheeler, Robert
Horton,
Phillip Sherrod, and Douglass Henry under the direction of Dr. George Haynam
of the Vanderbi It University Computer Center, Nashvi lie, Tennessee.
In cooperation with VanderbiIt University, Xerox Data Systems is making the FLAG Com-
piler available to those customers who require the characteristics of a fast load-and-go
FORTRAN.
The
reference material in this manual was largely taken from the XDS Sigma 5/7 FORTRAN
IV-H
Reference Manual (XDS 90 0966) though several important sections have been ex-
cerpted from the XDS Sigma 5/7 FORTRAN IV Reference Manual (XDS 900956), notably
all the material in Chapter 6 dealing with FORMAT statements and specifications and with
extended input/output capabilities. Furthermore, FLAG provides most of the function sub-
programs that are available to FORTRAN IV users. These subprograms are listed in "Table 9
Intrinsic and Basic External Functions", taken from the previously mentioned FORTRAN IV
Reference Manua I.
RELATED PUBLICATIONS
Title
XDS Sigma 5 Computer Reference Manual
XDS Sigma 7 Computer Reference Manual
XDS Sigma 5/7 Batch Processing Monitor Reference Manual
XDS Sigma 5/7 Batch Processing Monitor Operations Manual
XDS Sigma
5/7 FORTRAN IV-H Reference Manual
XDS Sigma 5/7 FORTRAN IV Reference Manual
XDS Sigma 5/7 FORTRAN IV Operations Manual
XDS Sigma
5/7 FORTRAN IV Library Technical Manual
NOTICE
Publication No.
900959
90 0950
900954
901198
900966
900956
90 11 43
90 15 24
The specifications of the software system described in this publication are subject to change without notice. The availability or performance of some features may
depend on a specific configuration of equipment such as additional tape units or larger memory. Customers should consult their XDS sales representative for details.
ii

CONTENTS
l.
INTRODUCTION
Input/Output Statements 28
How This Manual Is Organized
The FLAG Compiler 1
FLAG Programs 1
Conditional Compilation - X Cards 3
Formatted Input/Output Statements 29
Acceptable FORTRAN II Statements 30
Intermediate Input/Output Statements 31
END and ERR Forms of the READ Statements 32
NAME LIS T Statement 32
Simplified Input/Output 32
2. DATA 5 OUTPUT Statement 33
Limits on Values of Quantities
5
Constants 5
Integer Constants
5
Real Constants 6
Double Precision Constants 6
Complex Constants 6
Double Complex Constants
7
Logical Constants 7
Literal Constants 7
Identifiers
8
Variables 8
Sca lars 8
Arrays 8
Functions
9
INPUT Statement Using NAME LIST 34
FORMAT Statement 37
F Format (Fixed Decimal Point) 38
- E Format (Normalized, with E Exponent) 39
D Format (Normalized, with D Exponent)--- 40
G Format (General) -- 40
I Format (Integer) 42
L Format (Logical) 42
A Format (Alphanumeric) 43
R Format (Alphanumeric, Right-Justified) ___ 44
Z Format (Hexadecimal) 45
M Format (Machine Dependent) 46
H Format (Hollerith) 47
'Format (Hollerith) 47
X Specification (Skip; Space or Backspace) __ 48
T Specification (Tab) 49
3. EXPRESSIONS
10
P Specification (Scale Factoror Power of 10) 49
Arithmetic Expressions
10
Evaluation Hierarchy 10
Mixed Expressions 12
Relational Expressions 13
Logical Expressions 14
Logical Operators
14
Evaluation Hierarchy 15
/ Specification (Record Separator) 51
Parenthesized FORMAT Specifications 52
Adjustable FORMAT Specifications 53
Numeric Input Strings 54
Widthless Numeric Input 55
Numeric Input with Width Specified 56
Comma Field-Termination 56
FORMAT and List Interfac ing 57
4.
ASSIGNMENT STATEMENT
16
FORMATs Stored in Arrays 58
Extended Input/Output Capabilities 59
5.
CONTROL STATEMENTS
18
Memory-to-Memory Data Conversion 59
ENCODE Statement 60
Labels 18
DECODE Statement 60
GOT 0 Statem ents
18
Direct Input/Output 61
Unconditional GO TO Statement 18
BUFFER IN 62
Assigned GO TO Statement
18
BUFFER OUT 62
Computed GO TO Statement
19
Random Access Input/Output Statements 63
ASSIGN Statement
19
Auxi I iary Input/Output Statements 63
IF Statements
20 REWIND
Statement 64
Arithmetic IF Statement
20 BACKSPACE
Statement 64
Logical IF Statement
20 END
FILE Statement 64
CALL Statement
21
Carriage Control for Printed Output 64
RETURN Statement
22
DO Statement
22
CONTINUE Statement
25
7. DECLARATION STATEMENTS
65
PAUSE Statement
25
Classification of Identifiers 65
STOP Statement
25
Implicit Declarations 65
END Statement
26
Explicit Declarations 65
Confl icting and Redundant Declarations 65
6.
INPUT/OUTPUT 27
Array Declarations 66
Array Storage 66
Input/Output Lists 27
References to Array Elements 66
List Items 27
DIMENSION Statement 67
Special List Considerations
28 IMPLICIT
Statement 67
iii

Explicit Type Statements 68
APPENDIXES
Optional Size Specifications
69
Storage Allocation Statements
70
A. FLAG STATEMENTS 98
COMMON Statement
70
B.
DIAGNOSTIC MESSAGES
100
Labeled COMMON
71
Blank COMMON 71
Arrangement of COMMON 72
Referencing of Data in COMMON
73
EQUIVALENCE Statement
73
Interactions of Storage Allocation Statements _
75
ILLUSTRATIONS
EXTERNAL Statement
76
BLOCK DATA Subprograms
76
1.
Sample XDS FLAG Program 2
DA TA Statement
77
DATA Variable List
77
2.
Array Storage
66
DA TA Constant Li st 78
3.
FLAG Job Setup - Single Program
96
Placement and Order of Declaration Statements 79
4.
FLAG Job Setup - Multiple Programs in Batch
8. PROGRAMS
AND SUBPROGRAMS
80
Processing Mode 97
Main Programs
80
Subprograms 80
Statement Functions 80
FUNCTION Subprograms 81
SUBROUTINE Subprograms 82
TABLES
Arguments and Dummies 83
Dummy Scalars 84
l.
Sample Program 3
Dummy Arrays 84
2.
Mode of Mixed Expressions Using
Adjustable Dimensions 85
Operators + - * / 12
Dummy Subprograms 86
Library Subprograms 86
3.
Valid Type Combinations for Exponentiations 12
Basic External Functions
86
4. Evaluation of Logical Expressions 14
Additional Library Subprograms
86
r:::.
f\,~ixed VOiiob!e Types and Expression "-Aodes __
16
-'.
9.
OPERATIONS 93
6.
Standard Unit Assignments
28
Running a FLAG Job 93
7.
FORTRAN II/FORTRAN IV Equivalent Statements_
30
The FLAG Control Card 93
8.
Permissible Correspondences Between Arguments
Job Setup Examples
95
F LA G Debug Mode 96
and Dummies 83
9. Intrinsic and Basic External Functions
87
INDEX
104 10. FLAG Option Codes 94
iv

l
1. INTRODUCTION
How This Manual is Organized
Most of the material in this manual was taken from the Sigma 5/7 FORTRAN IV-H Reference Manual (XDS 90 09 66B),
though
several important sections are from the Sigma 5/7 FORTRAN IV Reference Manual (XDS 90 09 56C). For the
convenience of those who may already be familiar with XDS FORTRAN IV-H, material in this manual that differs from
the FORTRAN IV-H Manual is indicated by a bracket in the left hand margin of the page.
The remainder of this Chapter summarizes the most important features of FLAG and then briefly presents information
of general interest to the new user. Chapters 2 through 8 are a detailed description of the FLAG language. Chapter 9
contains the essential operations information for compiling and running FLAG programs.
Users
already familiar with XDS FORTRAN IV-H will probably perfer to scan Chapters 1 through 8 noting the changed
areas marked by brackets, and then read Chapter 9 for an explanation of FLAG operations. Such users wi II thus be
able to start running FLAG programs with minimum delay.
The FLAG Compiler
The FLAG (FORTRAN Load And Go) system for XDS Sigma 5/7 computers is essentially a FORTRAN IV-H compiler
designed to be compatible with other compilers of this class. However, FLAG provides to the user a unique set of
operating characteristics:
• Comprehensive diagnostic messages at compile and execute time.
• Fast compi lation.
• Significant reduction in total processing time for small-to-medium sized programs.
• Special accounting and processing features to minimize Monitor system overhead.
FLAG may be used in preference to standard FORTRAN compilers when the user is in the debugging phase of devel-
oping his program. Further, it should be the primary FORTRAN compiler system in the typical university environ-
ment where the job stream contains numerous small programs, many of which are written by novice programmers.
FLAG Programs
FLAG programs are comprised of an ordered set of statements that describe the procedure to be followed during exe-
cution of the program and the data to be processed by the program. Some data values to be processed may be exter-
nal to the program and read into the computer during program execution. Similarly, data values generated by the
program can be written out while processing continues. Statements belong to one of two general classes:
1. Executable statement/, that perform computation, input/output operations, and program flow control.
2. Nonexecutable statement/, that provide information to the compi ler about storage assignments, data types and
program form, as well as providing information to the program during execution about input/output formats and
data initial ization.
Statements defining a FLAG program follow a prescribed format. Figure 1 is a sample FORTRAN Coding Form. Each
I ine on the form consists of 80 spaces or columns; however, the last eight columns are used only for identification or
sequence numbers and have no effect on the program. Columns 1 through 72 are used for the statements.
The first field, columns 1 through 5, is used for statement labels. Statement labels allow statements to be referenced
by other portions of the program. Labels are written as decimal integers, with all blanks (leading, embedded, or
trailing) ignored. Chapter 5, IIControl Statements II, contains a more extensive discussion of statement labels.
tSee Appendix A.
Introduction

The body of each statement is written in columns 7 through 72, but if additional space is required, a statement may
be continued. FLAG accepts an unl imited number of continuation Iines. Each continuation I ine must contain a char-
acter other than blank or zero in column 6. The initial line of each statement contains only the characters blank or
zero in column 6. If a statement is labeled, the label must appear on the initial I ine of the statement; labels appear-
ing on continuation Iines are ignored.
Column 1 may contain the character C to indicate that the line is to be treated as a comment only, with no effect
upon the program. Comment lines may appear anywhere in the program, except within a statement (i.e., inter-
spersed with continuation lines).
Statements may have blanks inserted as desired to improve readabil ity, except within literal fields (e. g., in Hollerith
constants and in FORMAT statements).
The set of characters acceptable to FLAG is
Letterst: ABC D E F G H I J K L M N 0 P Q R STU V W X Y Z
Digits:
0123456789
Speci al characters:
(useful) t + - * / =
() • , $ I & blank
Special characters:
II
(other)
This
character set conforms to the Extended Binary-Coded Decimal Interchange Code (EBCDIC) standard.
Figure 1 illustrates a sample FLAG program. An explanation is given in Table 1.
PROBLEM Sa mpi e
S!:I:»ls
~ '---
SCIENT:FIC DATA SYSTEMS
FORTRAN CODING FORM
PROGRAMMER ____________________ _
Identification
FORTRAN STATEMENT
II NT EGE R FACTOR, K
I-r--.-.,--r---t"""""+-"', T I • , • ii' Ii' • • , i .·-,.--r··--~"T"-.,._r_r_l--y--r--rj-,--,--.,..--,r--r--.--.--...--.---.--,-- ...... ·
iK =
iii , • • • • ! ~. .,. ,'--' ,---r--r--r---r-...---r--.---r--r ..-,-,..---r-. -,-,........,-, -r,---.----.--r--.---.--.. --r""'-'--T-"-r-~
~-.--,.--r-+-! .....,lR.;;E=;A,D, ,( ,1, • ,5, ), , 'f~-,.~TR-,-T-·,--y---r--,.__,__.-,---r---.--r-......,........-r--T"'" ",-,---'---r--~..---r-,--r-r-I
hI.O~J,F, ,( ,F,A,C,T,~R,) ,l-1r,J-r3.,J .1, lr-~T-r--T-r-.--,---rl---r-.,...--,. y-1-.----.-.- T-,"'·"- ~-;-'-""---'
1 1 I lK = K • FAC T (j R
lJFACT6R = '
.... , ... .,-- ...... , '·~·-T--~-- ,---1'
12
13 WRI TE
(1 O'S , 6) 'K~'-' . -'~·TT-'~-,.- .. -T----r-r---.--' -r·-r-r-.-· ... I-..--
T ....
'-'-'---'-"--,---"
Iii ' iii i 1 iii I i * ---,---"'" ·--TM-"...-----r-- "'l"'--,. , i , i T~.--.--r-r-r--T • Iii ¥ ,.-.~
STC:SP
5 F eRMA T (t'6)
t--.-·-,-.--r-=6~f-'-+1~_.~R,M: ~ T . (::~ :",~-,_T"~ -., :-1""': ~-r_~-Q: f:=:-~=~·~..,...-y-~,---,--.--r. -r........-.,.--.,...-r. ~-r:---,---r-...,.....,r-T--r--,--,
'~';jEND
t--r-T-,-----r-+-+I,!=-r--"'- -.=....-,-, --.--.----r-.......-r,--r-, .--.--.----., ir---r-", ~"-r""""-'" "r ··Y· .... ,...........,.--....,.._·......--.-, ~, . ..,--.--......--,-._ . ....,.......,., --.--.-.- • ..,.....-rj -.-...,..---,.-~
-.. ------' --_ .... _-----------
Figure 1. Sample XDS FLAG Program
tThe
dollar sign ($) character is accepted, though not recommended, as a letter of the alphabet. It may therefore
be used in FORTRAN identifiers, such as $, FIVES, or $300. For the purposes of the IMPLICIT statement (see
Chapter 7), $ follows Z in the set of letters.
2 FLAG Programs

Line
1,2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
Table 1. Sample Program
Meaning
The character C in column 1 defines these I ines as comments.
A
nonexecutabl e statement that defines to the compiler the variabl es FACTOR and K as integers.
An assignment statement that sets K equal to 1.
An input command that causes the value of FACTOR to be read into storage. The value is read
from unit 1. The form in which the value of FACTOR appears external to the computer is speci-
fied by FORMAT 5 (line 14).
Statement 10 tests the value of FACTOR and transfers control to statement 11, 12, or 13 as follows:
If FACTOR < 0, control is transferred to statement 12.
If FACTOR =
0, control is transferred to statement 13.
If FACTOR > 0, control is transferred to statement 11.
Statement 11 is another assignment statement that assigns to K the value of the expression K times
factor. In other words, the current valueofK is replaced by the currentvalue of K multiplied
by the value of FACTOR.
The
statement appearing on lines 8 and 9 is an assignment statement, written as an initial line
and one continuation line.
The C in column6causesline9 to bea continuation of line 8. This statement assigns to FACTOR
the value of the current value of FACTOR minus 1.
When the GO TO statement is executed, an unconditional transfer of control to statement 10
(I ine 6) occurs;
Statement 12, an assignment statement, assigns the value zero to the variable K.
The WRITE output statement, 13, causes the name of the variable K and its value to be
written out on unit 108, which is normally assigned to the Printer (see statement 6, line 15
for
designated FORMAT statement).
The control statement STOP causes execution of the program to be terminated.
FORMAT statement corresponding to READ statement on line 5.
FORMAT statement correspond ing to WRITE statement on line 12.
The END
line informs the processor during compilation that it has reached the physical end of
the source program.
In this program, if the value of FACTOR is initially 3 as read .by line 5, statement 10 will be
executed four times, the statements on line 7 through 10 wi II be executed three times, and the
statements on lines 4, 5, 12, and 13 will be executed once each.
Conditional Compilation - X Cards
FLAG provides a means for conditional compilation of statements. Any line that contains an X in column 1
is processed as a statement only when the CX option is specified on the FLAG control card (see Chapter 9).
Otherwise, the card is treated as a comment.
Conditional Compilation - X Cards 3

This feature enables the programmer to include in his program additional statements for checkout purposes, such as
intermediate output and special error checking. When checkout has been completed, these statements do not have
to be removed from the program. Instead, the program is compiled without the CX option and the statements are
treated as comments only. These statements remain in the listing, however, and may serve as documentation or
checkout procedures. Also, they may easily be reinstated at any time.
Continuation lines for X cards should also be X cards; furthermore, a normal line may have a continuation line that
is also an X card. For example:
~
C FOR COMMENT
-lsTATEMENT J FORTRAN STATEMENT
NUMBER
1 5 6 7
10 15 20 25
30
35
40 45
X·
'l!r •• _,
A.
B .J ...•
. . .
:c~PRINT
3 •
C.
I I
X
D. E • F
3 FeRMAT ( X.
6F . 7')
.
. I
PR I NT
3 • U.
V. W
. I
x , X, YI ~
I I
-.~ .... ~-- .. --
4 Conditional Compi lotion - X Cards

2. DATA
Numerical quantities - constants and variables -as distinguished in FLAG are a means of identifying the nature of
the numerical values encountered in a program. A constant is a quantity whose value is expl icitly stated. For ex-
ample, the integer 5 is represented as 115
11
; the number IT, to three decimal places, as 113. 14211. A variable is a
numerical quantity that is referenced by name rather than by its explicit appearance in a program statement. During
the execution of the program, a variable may take on many values rather than being restricted to one. A variable
is identified and referenced by an identifier.
All data processed by a FLAG program can be classed as one of seven types:
Integer
Reai
Double precision
Complex
Double Compl ex
Logical
Literal
lim its on Values of Quantities
Integer data are precise representations of the range of integers from -2, 147,483,648 to +2, 147,483,647;
that is, -2
31
to +2
31
-1. Integer data may only be assigned integral values within this range.
Real data (sometimes known as floating-point data) can be assigned approximations of real numbers, the magnitudes
of which are within the range 5.398 x 10-
79 to
7.237 x 10
75
(i.e., 16-
65 to
16
63). A real
datum may acquire
positive or negative values within this range or the value zero. Real data have an associated precision of 6+ sig-
nificant digits. That is, the sixth most significant digit will be accurate, while the seventh will sometimes beaccu-
rate, depending on the value assigned to the datum.
Double precision data may approximate the identical set of values as real data. However; double precision data
have an associated precision of 15+ significant digits.
Complex data are approximations of complex numbers. These approximations take the form of an ordered pair of
real data. The first of the two real data approximates the real part, and the second real datum approximates the
imaginary part of the complex number. The values that may be assigned to each part are identical to the set of
values for real data.
Double complex data have the same form as complex data except that both the real and imaginary parts are double
precision values.
Logical data can acquire only the values IItrue
'l
or IIfalse
ll
•
Literal Data are character strings of up to 255 characters. Like logical data, literal data do not have numeric val-
ues. Any of the characters discussed in Section 1 may appear in literal data.
Constants
Constants are data that do not vary in value and are referenced by naming their values. There are constants for
each type of data. AI though numeric constants are considered as being unsigned, they may be preceded by the
pi us or minus operators. The operator is not considered part of the constant, however. (See Chapter 3.)
Integer Constants
Integer constants are represented by strings of digits. The magnitude of an integer constant must not exceed
2, 147,483,647.
Examples:
382
13
997263
1961
1000000000
323344224
000546
382437
8
o
Data 5