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Document:	VT55 Programming Manual
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VT55
Programming Manual
Order No. AA-4949A-TC

dlifgliltiall

February 1977
This document describes methods and available software for programming the
VTS5 terminal in the FORTR
AN and BASIC-PLUS languages.

VTS5
Programming Manual
Order No. AA-4949A-TC

SUPERSESSION/UPDATE INFORMATION:

For RT-11/FORTRAN users, this manual supersedes

Chapter 1 of the FORTRAN/RT-11 Extensions Manual

(DEC-11-LRTEA-C-D). For the other operating systems
it contains new information.

OPERATING SYSTEM AND VERSION:

RT-11 V02C
RSX-11M V03

RSX-11D V6.2
IAS V1.1
RSTS/E V6A
SOFTWARE VERSION:

FORTRANIV VIC
BASIC-PLUS V1
FORTRAN-IV PLUS V02

First Printing February 1977

The information in this document is subject to change without notice and should not be construed as a

commitment by Digital Equipment Corporation. Digital Equipment Corporation assumes no responsibility
for any errors that may appear in this document.

The software described in this document is furnished under a license and may be used or copied only in
accordance with the terms ofsuch license.

Digital Equipment Corporation assumes no responsibility for the use or reliability of its software on equipment that is not supplied by DIGITAL.

The following are trademarks of Digital Equipment Corporation.

COMPUTER LABS
COMTEX
DDT
DEC
DECCOMM

DECUS
DECsystem-10
DIBOL
DIGITAL
EDUSYSTEM

DECtape

FLIP CHIP

FOCAL
INDAC
LAB-8
OMNIBUS
OS/8
PDP
PHA

9/77-14

MASSBUS
RSTS
RSX
TYPESET-8
TYPESET-10

TYPESET-11
UNIBUS

CONTENTS

PREFACE

CHAPTER

GENERAL INFORMATION. . . ... ..

1.1

GETTING USED TO GRAPHIC TERMS

1.2

GRAPHIC FIGURES

1.3

CURSOR CONTROL . ... o
e

1.4

MATHEMATICALTERMS. . ...

1.5

TERMS FOR LARGE SYSTEMS

1.6

FURTHER READING

You will find the following manuals helpful if you need further information on BASIC-PLUS, FORTRAN,
operating systems, or the VT55 hardware.
Languages

BASIC-PLUS Language Manual

(DEC-11-ORBPB-A-D)
IAS/RSX-11 FORTRAN IV User’s Guide

(DEC-11-LMFUA-C-D)
PDP-11 FORTRAN Language Reference Manual

(DEC-11-LFLRA-C-D)
RT-11/RSTS/E FORTRAN IV User’s Guide

(DEC-11-LRRUA-A-D)

1-4

General Information

Operating Systems
RSX-11M Operator’s Procedures Manual

(DEC-11-OMOGA-C-D)
RT-11 System Reference Manual

(DEC-11-ORUGA-C-D, DN1, DN2)
RSTS/E Programming Manual

(DEC-11-ORPMA-A-D)
RSX-11M Executive Reference Manual

(DEC-11-OMERA-C-D)
RSX-11D Executive Reference Manual

(DEC-11-OXERA-A-D)
IAS Executive Reference Manual, Volume 1

(DEC-11-OIE1A-A-D)
[AS User’s Guide

(DEC-11-OIUGA-A-D)
VTS5 Hardware
VTS55-E,F DECgraphic Scope Users’ Manual

(EK-VTSSE-TM-001)

1-5

CHAPTER 2

FORTRAN PROGRAMMING

2.1

INTRODUCTION TO PLOTSS

FORTRAN control of the VTS5 is provided by a single subroutine called PLOTSS. A call to this routine
from your main program has one of the following two forms:

CALL PLOTSS(ICMD,IX,IY,ITBL)
or

CALL PLOTSS(ICMD,IX,IY)
ICMD, IX, 1Y, and ITBL, the arguments of PLOTSS5, must all be integers or, in certain cases, integer arrays.
The arguments have the following meanings in the three-argument form of PLOTSS:

ICMD defines the procedure that will be carried out by a single call to PLOTSS.

IX is, in most cases, the x coordinate of, for example, a point to be plotted on the VTS5
screen. The specific use of this argument varies depending on the procedure being per-

formed (i.e., depending on the value of ICMD). Its use will be explained for each procedure
in the next section.

1Y is, similarly, the y coordinate of
a point. Its use will also be covered for each procedure.
The purpose of ITBL, which is a 16-element integer array, is to provide a storage space that PLOTS55 can

use to store status information (e.g., which graphic figures are enabled) from one PLOTSS call to the next.
For this reason, ITBL is called a status table. If you do not specify the fourth argument, PLOTS55 will use an
internally defined array for the same purpose. The use of this fourth argument in RT-11 FORTRAN pro-

grams usually makes no difference in the way your PLOTSS program functions (see Appendix B ofthis
manual for some important exceptions). When you do specify ITBL, begin your program with the statements:

INTEGER ITBL(16)
DATA ITBL/16*0/

These statements a) define a 16-element array called ITBL, and b) fill the array with zeroes. Remember

that the ITBL must be initialized (as with the DATA statement above) at the beginning of each new
PLOTSS program.

2-1

FORTRAN Programming

NOTES

Do not use both three- and four-argument

forms of PLOTSS in the same program,
since doing so would effectively create two

separate ITBLs.
2.

If you use the four-argument form in an
overlaid program, ITBL must be placed in
the root of the overlay so that all PLOTSS
calls can gain access to it.

RSX-11 and IAS users must use the four-argument version of PLOTSS

at all times.

2.2 PLOTS5 PROCEDURES
There are 14 procedures that you can control by changing the value of

ICMD in CALL PLOTSS (ICMD,
IX, 1Y LITBL)). ICMD can be any integer in the range 0 to 13, with the results
described in this section.
NOTE
In many cases, you do not have to specify all three

(or four) arguments in a PLOTSS call. However,

three-argument calls must always contain two commas,

and four-argument calls, three commas.
PLOTSS5 programs will function unpredictably if

any commas are left out.

2.2.1

Attaching and Detaching a Terminal (RSX-11 and IAS Only)

Format:

CALL PLOTS5(0,IJLUN,IEFN,ITBL)

ILUN is the logical unit number and IEFN is the event flag number.

If ILUN is -1, the VTS5 terminal is detached. If ILUN is a positive integer (1-12), the logical
unit specified by ILUN is attached to the task being executed and will not accept input from
another task.

IEFN, the event flag number (1-32), is important in controlling the scheduling of tasks in a
multitask system. A detailed explanation of this number is beyond the scope of this book, but

more information can be found on this number (and the logical unit number) in the Executive Reference Manual for your system.

The actual function of ICMD=0 is to store the logical unit number (ILUN) and event flag number (IEFN)
in the status table (ITBL). Once this function is performed, all output from PLOTS5S5 calls (graphic and alphanumeric instructions) is sent to the device associated with ILUN.
The ICMD=0 call does not associate ILUN with the VT55; you must do that job separately, using any of
several methods available to users of IAS, RSX-11M, and RSX-11D. The system directive ASNLUN is one

such method. ASNLUN can be written into your program as if it were a FORTR
AN subroutine:

CALL ASNLUN (1,'TT’,17)

In this example, 17 is the octal terminal number of the VTS5, so that logical unit 1 is associated with physical device TT17:. Note that if this call were written into a program that was run from TT15:, for example,
2-2

FORTRAN Programming

the VTS5 would only display information created by PLOTSS. Unless you reassigned logical units 5 and 6

as well, these numbers would continue to refer to the terminal interface (TT15:) and the line printer,
respectively. You could therefore keep the VTS5 screen free of unwanted alphanumeric displays, such as
the messages created by PAUSE statements.

In any case, it is best to use ASNLUN or some other method to assign ILUN to the VTS5 before you call

ICMD=0. See the documentation for your operating system for alternative methods of making this assignment.

Appendix B suggest

a FORTR
AN subroutine that performs the assignment and attachment in a single

call.

NOTE

ICMD=0 is useful only under the RSX-11 and [AS
systems. This command form can appear in RT-11
programs, too, but will not perform any operation.

2.2.2

Graphic Procedures

Select Graph Number (ICMD=1)

Format:

CALL PLOTSS (1,IGRF,[,LITBL])

IGRF, always either O or 1, specifies the graph number of the next graph (regular or shaded)
to be plotted. This number will be the label of the next regular or shaded graph to be plotted
and will be the label of that figure as long as the figure is enabled. Note that this value of

ICMD does not display or plot a graphic figure but only identifies the register that will contain
the plotting values for the graph. Plotting the figure actually loads this register with plotting

values (see ICMD=3), and enabling the figure (ICMD=2) allows it to appear on the screen as
soon as it 1s plotted.

Enable or Disable Graphic Figures ICMD=2)

Format:

CALL PLOTS5S (2,IENAB,IDISAB[ITBL))

This call is the "fundamental” form of PLOTSS, because graphic figures cannot be displayed
until they have been enabled. Therefore, you will, in most cases, want this form to be one of

the first calls to PLOTSS in your program. Of course, this form can also appear later in the
program if you want to enable some new figure or to disable a figure that is already on the
screen.

IENAB and IDISAB are lists of figures to be enabled or disabled, respectively. You can use
the following values in these two lists:

= Enter (leave) graphic mode.

Enable (disable) Graph 0.

= Enable (disable) Graph 1.

= Enable (disable) Shaded Graph 0.

2-3

FORTRAN Programming

= Enable (disable) Shaded Graph 1.

= Enable (disable) horizontal lines.

= Enable (disable) vertical lines.

128

= Enable (disable) markers for Graph (or Shaded Graph) O.

256

= Enable (disable) markers for Graph (or Shaded Graph) 1.

512

= Disable all graphic figures and clear the graphic memory (IENAB only).

To enable or disable more than one figure in a single PLOTSS call, you can enter lists of numbers, separated by plus signs, for IENAB or IDISAB. For example, instead of putting the
number 1 in the IENAB position (to enter graphic mode), you could put 1+2+4+512, which
would first clear the graphic memory and then enter graphic mode and enable Graph 0 and
Graph 1.
NOTES

If you enter the same number for both IENAB

and IDISAB, the graphic figure for that number
will be enabled.

You can also enter the sum of several numbers

rather than a list, e.g., the number 24 (instead of
8+16) to represent both shaded graphs. However, your program will be more easily understood
by other users if you avoid this practice.
3.

As a matter of good practice you should always
include the 512 argument in the IENAB posi-

tion

the

first time

you

call

PLOTSS

with

ICMD=2,e.g.,

CALL PLOTS55(2,1+512+2,)
This three-argument example would put the
terminal in graphic mode, enable Graph 1, and

also would clear all previous graphic information from the status table and memory. If you
were running several graphic programs in se-

quence, the 512 would erase the graphic output
of the last program from the screen before displaying a new figure. (Notice also that in the
sample call above, the IDISAB position is empty, indicating that no graphic figures are being
disabled, but that the "trailing" comma s still included.)

It is usually not desirable to enable different figures with the same label (for instance, both
Graph 0 and Shaded Graph 0).

2-4

FORTRAN

Programming

Plot Graph (ICMD=3)

After you have enabled a graph and selected its label (ICMD=2 and ICMD=1, respectively),
you can use ICMD=3 to plot the figure.

Format:

CALL PLOTSS(3,IX,IY[ITBL))
or

CALL PLOTS5(3,IX,JARRAYL[ITBL])
When the first format is used, ICMD=3 will display a single point on the screen at the coordi-

nates given by IX (0-511) and IY (0-235).
When you use the second format, IX should be a negative integer and IARRAY an integer

array that you have previously filled with a series of values. In this form, ICMD=3 will plot a

series of points on the screen. The number of points plotted will be the absolute value of IX;
the same number of y coordinates will be selected from IARRAY, starting with the first element of the array; and the points will be separated by one unit in the x direction.
For example,

CALL PLOTS55(3,100,100)

will plot a single point on the screen at a position 100 units from the bottom of the screen (y=
100) and 100 points from the left edge (x=100).
The other form,

CALL PLOTS55(3,-100,ISINE)
would plot a sine function on the screen (assuming that ISINE has been identified in a DIMENSION statement and filled with sine values before this call to PLOTS5S5). The sine
function would be made of 100 points (the absolute value of IX=-100), and each point would
be separated from neighboring points by one x unit on the screen.
NOTE
It is generally necessary to define a starting x posi-

tion (ICMD=7) before plotting regular or shaded
graphs. It is not possible to assign two or more y val-

ues to the same x value in a single graph; therefore,
vertical lines cannot be plotted with ICMD=3.

Example 1 demonstrates the use of ICMD=1, ICMD=2, and ICMD=23 to display a series of

functions on the VTS5 screen.

2-5

FORTRAN.Programming

Example 1

(2 C2(2

(202 (2

INTEGER ARYSIN(500),ARYCIS(500),ARYEXP(500)
DATA P1/3,14159/
ENABLE

GRAPHIC

MODE

AND

GRAPHS

CALL

PLOTS55(2,1+2+4+512,)

FILL

I=1,500

THE

COSINE,

SINE

AND

EXPONENTIAL

ARRAYS

EXPARG=1/50,

THETA=PI*¥EXPARG

(24) () (2 W

ARYSIN(I)=SIN(THETA)*100.+100,

ARYCOS(1)=COS(THETA)*100,+100,
ARYEXP(I)=EXP(EXPARG)
DEFINE

STARTING

SINE

THE

CALL
CALL
CALL

PLOT55(7,0,0)
PLOTS55(1,0,)
PLOTS55(3,=500,ARYSIN)

(24203
N

READ(5,2)

() €() Q2
(20202
()

(0,0),

SELECT

GRAPH

PLOT

THE

CALL
CALL

PLOTSS5(1,1,)
PLOTS55(3,=-500,ARYCDS)

ENABLE

CALL

COSINE

THE

FUNCTION

GRAPH

SHADED

GRAPHS

AND

DISABLE

GRAPHS

GRAPH

AND

THE

PLOTS55(1,0,)
PLDT55(3,-500,ARYEXP)
PLOTS55(1,1,)
PLOTS55(3,-500,ARYCOS)

DISABLE

SHADED

GRAPH

(THE

COSINE

FUNCTION)

PLOTS55(2,,16)

READ(5,2)

REENABLE GRAPH O AND
[THE EXPONENTIAL TO A

CALL

THE

PLOTS55(2,8+16,2+4)

READ(5,2)

CALL

PLOT THE EXPONENTIAL AS SHADED
COSINE AS SHADED GRAPH 1,

CALL
CALL
CALL
CALL
(3¢
€2

FUNCTION

FORMAT(IZ2)

READ(5,2)

(20C2€2
02

COORDINATES

PLOT

DISABLE
REGULAR

PLOTS55(2,2,8)

READ(5,2)
END

2-6

SHADED
GRAPH,

GRAPH

CHANGING

AND

FORTRAN Programming

Notes on Example 1:

The subroutine PLOT55(7,0,0) defines a starting x position (x=0) for all the graphs to be displayed by the program. Unless you want to change the starting position of graphic figures,
you do not have to repeat this call.

The statements READ(5,2) KR are used in this example to make the program pause between each graphic display. Each time this statement is reached, the computer will attempt to

read a character from the keyboard (logical unit 5); when you type a carriage return on the
keyboard the program will continue.

FORTRAN provides a better method, the PAUSE statement, for doing the same thing, but
using it will make the letters "PAUSE--" appear on the screen each time the program reaches

a PAUSE statement. A later example will show you how to remove this sort of undesired text

from the screen. (IAS/RSX-11 users: see Section 2.2.3 for a further discussion of the PAUSE
statement.)
3.

At this point, you should try running this example program. It will function as follows:

a)
b)

First, Graph 0, a sine function, will be traced out on the screen of the VT55 by 100 dots.
Type a carriage return, and Graph 1, a cosine function, will also appear. Notice that the
sine and cosine functions have the same starting x position.

Type another carriage return, and both graphs will disappear and be replaced by Shaded
Graphs 0 and 1, which represent the exponential and cosine functions, respectively.

Type another carriage return and Shaded Graph 1 will be disabled, making the cosine
function vanish.

Typing a final carriage return will disable the shaded graphs and reenable Graph 0. This
time the Graph 0 label is given to the exponential function, so the shaded graph of the

exponential will be replaced with a regular graph of the same function.

Plot Horizontal Line (ICMD=4)

Format:

CALL PLOTS5(4,IDISP,IY[,ITBL])

This form is used to either erase or display horizontal lines that span the entire width ofthe
screen.

IDISPisset to O to erase aline or to 1 todisplay a line.

'Y gives the y coordinate (0 to 235) of the line to be erased or displayed.

2-7

FORTRAN Programming

Plot Vertical Line ICMD=5)

Format:

CALL PLOTSS5(5,IX,IDISP[,ITBL])

This form is very similar to the previous ICMD=4, but controls vertical rather than horizontal lines. Note that the position of IDISP is different for this format than for ICMD=4.

IX gives the x coordinate (0 to 511) of a vertical line to be erased or displayed.
IDISP is set to 0 to erase a line or to 1 to display a line.

Example 2 demonstrates the use of both line types.

Example 2

THIS SAMPLE PROGRAM SHOAS HOW TO DRAAN AND ERASE

HORIZONTAL

BLEGIN BY RESETTING THE GRAPHIC MEMORY (THE 512

)

CALL PLOTS55(2,1+432464+512,)

NEXT DRAWN 51 VERTICAL LINES

ARGUMENT)

CALL

AND

VERTICAL

ENABLING

LINES

BJIH

LINE

TYPES

I=2,502,10

PLOTSS5(5,I,1)

READ(S,2)

FORMAT(AZ2)

NOAN DRAW IN 24 HORIZONTAL LINES TO FJIRM A GRID

)

DO 3 1=2,232,10

CALL

PLOISS5(4,1,1)

READ(S5,2)

tRASE THE VERTICAL LINES

DO 4
CALL

1=2,502,10

PLOT55(5,1,0)

END

Notes on Example 2:

As the example shows, ICMD=4 and ICMD=5 can each be used to either erase or display horizontal and
vertical lines. Again, the READ statement is used to insert temporary pauses, preventing unwanted text
from appearing on the screen.

FORTRAN Programming

Plot Markers ICMD=6)

Format:

CALL PLOTS55(6,IX,IDISP[,ITBL])

With this command, you can place markers (short vertical line segments) at any points on a
regular or shaded graph. The markers for Graph 0 and for Graph 1 must be enabled separately (see ICMD=2).
When you call PLOTS55 with ICMD=6, markers will be displayed on the graph that has cur-

rently been selected (see ICMD=1). The following example illustrates a common error:

CALL PLOTS55(2,1+244+4256,) (Enable both graphs and markers for Graph 1)
CALL PLOTS55(1,0,)

(Select Graph 0)

CALL PLOTS55(6,50,1)

(Plot marker at x=50)

This example will not work, because the second call selected Graph 0, and only the
markers for Graph 1 have been enabled. If you plan to use markers in a graphic display,
avoid this problem by enabling both sets of markers when you use both Graph 0 and

Graph 1 (or Shaded Graph 0 and Shaded Graph 1). You will still have to be careful, of
course, to ensure that a marker is placed on the correct graph.
[X, an integer from 0 to 511, gives the x coordinate at which the marker will appear. If a

graph exists at that x position, the marker will appear on the graph; if there is no graph at that
X position on the screen, the marker will appear on the y=0 line at the bottom of the screen.

IDISP will cause the marker to either be erased (IDISP=0) or displayed (IDISP=1).
Example 3 demonstrates the proper use of markers.

2-9

FORTRAN

Programming

€)
€2 €2

Example 3

THIS

PROGRAM

GRAPHS

DEMONSTRATES

AND

SHADED

THE

USE

MARKERS

GRAPHS

RESET THE GRAPHIC MEMORY, ENTER GRAPHIC MODE,
AND ENABLE GRAPH 0 AND MARKERS FJR GRAPH 0

CALL

PLOTSS(2,512+1+2+128,)

FILL

THE

(2¢42€2
=

(1€

(€2

(2020202

INTEGER ARYSIN(500)
DATA PI/3.14159/

(2220
00
W

SINE

FUNCTION

GRAPH

PLOTIS55(7,0,0)
PLOT55(1,0,)
PLOTS55(3,-500,ARYSIN)

PUT

A
3

MARKER

GRAPH

EVERY

UNITS

1=25,500,25

CALL PLOT55(6,I1,1)
READ(5,2) KR
NON

DISABLE GRAPH
PLOTTING THE SINE

CALL

REMOVE
DO

4
CALL
READ
END

AND

ENABLE SHADED
SHADED GRAPH

GRAPH

PLOIS5(2,8,2)

READ(5,2)
) €2 Q2

READ(5,2) KR
FORMAT(IZ2)

WITH

PO 1 I=1,500
ARYSIN(I)=SIN(PI¥I/50,.)%100,+100,
DEFINE STARTING X COORDINATE, SELECT
PLOT THE SINE FUNCTION,

CALL
CALL
CALL

(2€2¢€2102

ARRAY

THE

MARKERS,

1=25,500,25
PLOT55(6,I1,0)
(5,2) KR

BUT

LEAVE

THE

SHADED

GRAPH

AND

FORTRAN Programming

Define Starting Coordinates ICMD=7)

Format:

CALL PLOTSS(7,IX,IY[,LITBL])

This call defines the starting x position for regular or shaded graphs (ICMD=3) and the starting x and y positions for vectors (ICMD=8). PLOTSS will read the x and y coordinates that
you supply as IX and 1Y and will store them in its status table.
[X should be an integer between 0 and 511.
1Y, also an integer, must be between 0 and 235.

Note that when you draw vectors (ICMD=8), the starting coordinates change each time you
draw a vector. If, for instance, you want several vectors to start from the same point, you have
to redefine the starting coordinates (with ICMD=7) before drawing each vector.
When you draw graphs, the starting y coordinate will be supplied in your ICM D=3 call, as the
first element of [ARRAY.
NOTE

The starting coordinates you define do not affect
the placement of single points by the ICM D=3 call.
For example,

CALL PLOTS55(3,100,100)
will always plot a point 100 units from the left of the

screen and 100 units from the bottom, regardless of
the starting coordinates you have defined.
Draw Vector (ICMD=8)

Format:

CALL PLOTSS5(8,IX,IY[,ITBL])

After you have defined starting coordinates with ICM D=7, you can use this call to draw line

segments on the screen. The first vector you draw will start at the previously defined starting

coordinates and end at the point (IX,1Y).
[X, an integer from O to 511, is the x coordinate of the destination of the vector.
IY, which can be from 0 to 235, is the y coordinate of the destination.
For example, the series

CALL PLOT55(7,100,100)
CALL PLOT55(8,150,150)

will draw a vector from (100,100) to (150,150).

2-11

FORTRAN Programming

NOTE
After drawing a vector to (IX,IY), ICMD=8 resets
the starting coordinates to (IX,IY). If you draw a series of vectors, each one (except the first) will start
where the previous vector ended. It is not possible
to draw an absolutely vertical vector, because no

two y values can apply to the same x coordinate for

the same graph number.

Example 4 demonstrates the use of Define Starting Coordinates and Draw Vector calls. Notice that ICMD=7 is only used once, so that the vectors will be connected to each other.

THIS PROGRAM SHOWS HOW TO DEFINE STARTING JOORDINATES
AND HOW IO PLOT VECTORS,
IT WILL DRAW A DIAMIND IN THE
MIDDLE OF THE VT55 SCTREEN,
CLEAR

FIRST

CALL
THEN
CALL

()€1 (C)

(3¢2C)ClC

Example 4

STARTING

(2¢2¢C)
i

(2202021002

CALL
CALL

GRAPH

FOR

THE

COORDINATES

DRAW

WHERE

THE

THAT

THE

TOP
THE

TWO

AND
TJP

FIGURES,

ENABLE
OF

THE

GRAPHS
DIAMOND

AND

DEFINE

(100,100)

LINES

SECOND

FIRST

LINE

PLOTS55(8,150,150)

CALL

PLOTS55(8,200,100)
SELECT

GRAPH

USING

LINE

WILL

ICMD=8
BE

(DRAW

DRAWN

VECTOR),

STARTING

ENDED,

CALL

NOw

GRAPHIC

PLOT55(1,0,)
PLOIS55(7,100,100)

NOTICE

FOR

THE

BOTTOM

TWJ

LINES

AND

DRAW

THEH4,

cALL
CALL
CALL
READ
(2€¢(2C2¢C2(C2

SCREEN

PLOIS5(2,512,)
ENTER GRAPHIC MOJDE
PLOTIS5(2,1+2+4,)

SELECT

NOW

THE

PLOTS55(1,1,)
PLOTS55(8,150,50)
PLOTS5(8,100,100)
(5,1) KR

FORMAT(12)

DEMUONSTRATE
JN THE

FIGURES

DIAMOND

CALL

B3Y

THE FATT TI'HAT
STCREEN, ERASE

DISABLING

GRAPH

PLOTSS(2,,4)

END

2-12

1.,

THERE ARE TwW0O
THE BOTTOM OF

SEPARATE
THE

FORTRAN Programming

2.2.3

Alphanumeric Procedures

Position Cursor (ICMD=9)

Format:

CALL PLOTS55(9,IX,IY[,ITBL])

This simple command positions the cursor at the point (IX,IY).
[X can be from 0to 79; and
IY can be from 0to 23

You can use this command to decide where the next display of alphanumeric characters will

appear on the screen. IX will give the column number (with 0 being the leftmost column)
and IY will be the line number (line 0 is the top line on the screen).
Erase from Cursor to End of Screen ICMD=10)

Format:

CALL PLOTS55(10,,[ITBL])
NOTE

The "x" and "y" positions are always empty, but you

must still include the two commas (three if ITBL is
specified).
This command erases all alphanumeric characters from the present cursor position to the

end of the screen. The position of the cursor is not changed by ICMD=10.
Graphic figures are not affected by ICMD=10.
The subroutine CLEAR, shown in Example 5, uses ICMD=9 and ICMD=10 to clear the entire screen.

CLEAR functions by first returning the cursor to the home position:

CALL PLOT55(9,0,0)
and then erasing from this position to the end of the screen:

CALL PLOTS5(10,,)
Erase from Cursor to End of Line ICMD=11)

Format:

CALL PLOTS5S5(11,,[,ITBL])

This call performs the same sort of procedure as ICMD=10; but it only erases text from the
present cursor position to the end of the line. As with ICMD=10, the erasure does not
change the cursor’s position, nor does it change the status of graphic figures.

2-13

FORTRAN Programming

Display Text ICMD=12)

Formats:

CALL PLOT55(12,’ANY TEXT STRING’[,ITBL])
or

CALL PLOTS5(12,ICHARS,JALPHA[ITBL])
Both formats will display strings of alphanumeric characters, with the first character appearing at the cursor position.

The first format will display any text string that is inserted between the single quotation
marks; in the example shown here, the letters ANY TEXT STRING would appear at the

cursor position. The second format can function in two modes, both of which display characters from the "alphanumeric array,” IALPHA. These modes are selected by the argument
ICHARS.

If ICHARS is omitted or i1s 0O, PLOTSS5 will display characters that are listed in the third argu-

ment until it finds a NUL character (000). The example with a text string in single quotes
shows this mode in operation, because FORTRAN automatically puts a NUL at the end of
text strings in single quotes.

If ICHARS is some positive integer, it will determine the number of characters from IALPHA that will be displayed.

Example 5 shows how to display alphanumeric text with the use of ICMD=10, ICMD=11,
and ICMD=12. Notice that a NUL character (000) is loaded into the last word of IALPHA to
provide an end mark.

(2€202¢€2C2C202
€202

Example
5

THIS PROGRAM DEMONSTRATES ALL OF THE "ALPHANUMERIC"

FORMS OF

PLOTSS,

ICMD = 9 AND ICMD = 10 ARE USED IN A SUBROUTINE CALLED
"CLEAR," WHICH ERASES EXTRA TEXT FROM THE SCREEN,
AS A PRELIMINARY STEP TO ICMD = 12, YJU MUST DEFINE AN
"ALPHANUMERIC ARRAY" THAT CAN BE USED TO STORE TEXT:

(2C¢2€2C2C2C2¢2

LOGICAL*1 IALPHA(B1)
DATA IALPHA/80%' *,0/

THE LAST WORD IN IALPHA MUST BE 000,

WAHICH WILL BE

INTERPRETED AS A "NULL" ZHARACTER AND WILL TELL 1TMD = 12
IO STOP DISPLAYING CHARACTERS FRJOM IALPHA.

CLEAR THE STATUS TABLE AND THE SCREENZ
CALL

CLEAR

CALL PLOTISS(2,512,)

2-14

(2€02(€2C2

FORTRAN Programming

PUT THE
DISPLAY

CURSOR AT THE
A MESSAGE:

€2C¢2¢€20C)

CALL PLOT55(9,0,12)
CALL PLOTS55(12,,’WHEN
SYMBOLS WILL VANISH?

BEGINNING

LINE

ANC

YOU TYPE A CARRIAGE RETURN,
(1234567890)<>*+@#%&°)

THE

READ(S5,1) KR
FORMAT(I12)

THESE
AFTER

CALL
CALL

TWJ. PLOTSS
"VANISH:",

CALLS

WILL

ERASE

ALL

THE

CTHARACTERS

PLOTS5(9,60,12)
PLOTS55(11,,)

(2¢202¢C2

(202 ¢

PAUSE

TYPE

ANOTHER

CALL

CLEAR

NOW

WE'LL

USE

CHARACTERS

CALL
CALL
A

(2€C2C2€2C2C€2C2C)
(1)

ALPHANUMERIC

TYPE

ERASE

ARRAY,

THE -SCREEN

AGAIN,

FILLING

WITH

FROM

THE

KEYBOJARD,.

PLOT55(9,0,12)
PLOTS5(12,,'TYPE
UP TO

ONE

LINE

CHARACTERS

AND

RETURN’)

PLOT55(9,0,14)

READ(5,2)

(v ¥

THE

YOU

CARRIAGE

CALL

CARRIAGE RETURN

(IALPHA(J),J=1,80)

FORMAT(80A1)
CALL CLEAR
STATEMENT

WILL

BECAUSE

PLOTSS

"NULL"

CHARACTER

YOU

WILL

STATEMENT

I'0O

THE

CALL
CALL

WILL

DECIDE

DISPLAY

IN
HOW

PROGRAM®’S

ALL

KEEP

THE

GOING

UNTIL

YJU

HITS

CHARACTERS

WILL

(1-80)

ENTERED,

THE

IALPHA(81),
MANY

TYPING

INTEGER

DISPLAYED
IN

RESPONSE

REQUEST,

PLOTS5(9,0,12)

CALL

PLOISS(12,,IALPHA)
PLOT55(9,0,14)

CALL

PLOTSS5(12,,'TYPE

NUMBER

READ(5,4) LCHARS
FORMAT(I2)

CALL

PLOTS55(9,0,14)

CALL
CALL

PLOTIS5S(11,,)
PLOTI55(12,ICHARS,IALPHA)

PAUSE

ALL

CHARACTERS

CLEAR

END

2-15

CHARACTERS

AND

<CR>:’)

FORTRAN Programming

SUBROUTINE

CALL
CALL

CLEAR

PLOTS55(9,0,0)
PLOT55(10,,)

RETURN
END

NOTE

In IAS operation, the PAUSE statement is ignored.
The READ statement should be used instead. In
RSX-11 systems the PAUSE statement will suspend the task, which must be restarted with the
MCR command RESUME:

>RES taskname <CR >
Merely typing a carriage return will not resume the
task in RSX-11. When you run an RSX-11 task con-

taining PAUSE statements, give it a specific task
name, for instance:
RUN EXAMI/TASK=EXAM <CR >

where EXAMI1.TSK is the name of the file containing the task and EXAM is the name that would be
used in the RES command.

2.2.4

Sending Escape Sequences

Format:

CALL PLOTSS5(13,ICHAR,[,ITBL])

This command reads a number that you insert in place of ICHAR, puts an <ESC> character (033 octal)

in front of it, and sends those two characters to the VT35. This sort of character pair is called an "escape

sequence," and it tells the VTS5 to do the following:

Enter escape mode.

Return to the previous mode (i.e., graphic or alphanumeric) when the procedure is finished.

Perform a procedure specified by your choice of ICHAR.

I[CHAR is a decimal integer. The values you can enter for ICHAR are listed below along with the pro-

cedures they invoke:

ICHAR value
65

67
72
74

Procedure
Move cursor up one line

Move cursor right one position.
Move cursor to home position.
Erase from cursor to end of screen.
2-16

FORTRAN

Programming

Erase from cursor to end of line.

Hold screen.

Release screen.

Copy from top of screen to cursor.

Start automatic copy.

Stop automatic copy.
NOTE

If you'send an escape sequence that does not constitute an executable command, the VT55 will enter
escape mode and then automatically return to the
previous mode, without performing any operation.

The same holds true if you use an ICHAR in the
range 93-95 and your VT35 has no hard copy unit.

Several of the PLOTSS forms, particularly the ones which are alphanumeric functions, work by sending
escape sequences to the VTS5, For example, the forms

CALL PLOTS5(11,) and
CALL PLOTS5(13,75))
do exactly the same thing: erase from the cursor to the end of the line.
By using escape sequences, you can simplify some operations considerably. Suppose you wanted
to move
the cursor along the 20th line of text one character at a time. You could say

DO 11=1,80

J=I-1
1

CALL PLOTS55(9,],19)

But the same procedure is accomplished by saying

CALL PLOTS55(9,0,19)
DO 11=1,80

CALL PLOT55(13,67,)

Using ICMD=13 eliminates the computation of J=I-1 (which would be done 80 times), but more importantly, ICMD=13is a "simpler" command on the assembly language level and will be executed
more quickly. Each of the 80 times ICM D=9 is used, the ICMD=9 macro routine is called and then it calls seven additional routines to home the cursor, read the value of IX (even though, in this case, IX is the
same all 80

times), and repeatedly send escape sequences to move the cursor 20 lines down from the home position.
Therefore, the execution speed of your program will nearly always benefit if you use ICMD=13
possible.

as much as

The Hold Screen and Release Screen commands disable and reenable (respectively) the VTS55’s automatic

scrolling feature, that is, the feature that moves text up on the screen when you type more than

2-17

24 lines.

FORTRAN Programming

After you have displayed a graph on the screen, you may want to temporarily prevent the computer from

printing out the usual STOP message (or whatever your operating system normally displays at the end of a
FORTRAN program). Suppressing such messages is useful for appearance’ sake and nearly always
desirable when you make a hard copy of the screen contents. The following sequence at the end of your
program will accomplish this task:

900
901

CALL PLOT55(9,79,23)
CALL PLOT55(13,91,)

902

PAUSE

903

CALL PLOT55(13,92,)

904

END

Statement 900 moves the cursor to the last position on the screen. Then Line 901 effectively ‘freezes‘ the
screen so that the computer cannot display characters; the characters ‘PAUSE--* are transmitted back to
the VTS5, but because the scrolling is disabled they are not immediately displayed. The computer can still

read the VT5S5 keyboard, however, so that when you type a carriage return (or a RESUME command in
RSX-11), Statement 903 will be executed, releasing the screen. If your VTS5 has a built-in hard copier, you
can copy the contents of the screen (both graphic and alphanumeric) by pressing the orange COPY key on
the keyboard before typing the carriage return to release the screen. In any case, after releasing the screen,
you will have to push the orange SCROLL key a few times to scroll up the messages that were transmitted
while the terminal was in Hold Screen mode.

The escape sequence value 93 is the programmed equivalent of manually pressing the COPY key on the

keyboard; it will create a copy of everything on the screen from the top up to the cursor position, including
graphic displays. Remember to position the cursor at the end of the screen--

CALL PLOTS55(9,79,23)
before copying the screen.

The escape sequence values 94 and 95 start and stop the automatic copy feature of terminals with a built-in
hard copier. Automatic copying should only be used with alphanumeric text; graphic displays will be distorted if copied in this mode. When the VT55 receives a command to start automatic copying, it copies the
contents of the screen beginning at the top and continuing up to but not including the line containing the
cursor. Then one additional line of text will be copied each time you type a LINE FEED on the keyboard.
Automatic copying is especially useful for creating permanent listings of programs and subroutines that
you write. This automatic mode can be started and stopped manually by holding down the SHIFT key
while you press the COPY key.

Example 6 contains a program that allows you to examine the effects of various escape sequences.

For more information on escape sequences, see the VI55-E,F DECgraphic Scope User’s Manual (EKVTSS5E-TM-001).

Programming

FORTRAN

N=NNNAQNNNNANAOANAONNONONMONONNNONONO

Example 6

THIS

PROGRAM

WHICH

SENDS

THE

PROGRAM

WILL

YOU

TYPE

THE

WILL

BECOME

PERFORM

SOME

THE

READ

VTS5

ARGUMENT

OPERATION

IN
ON

ENTER,
FOLLOWS:

MOVE

CURSOR

MOVE

THE

MOVE

CURSOR

STOP

UP
TO

ERASE

FROM

HOLD

SCREEN,

RELFASE
VT55

HAS

COPY

FROM

START

STOP

READ(S,2?2)

LINE,

ONE
THE

HARD

TOP

AUTOMATIC
TYPE

POSITION

END

PLUOTSS(13,ICHAR,O0)
1

EwD

2-19

UNIT

SCRFEN
PRINT.

PRINT,

99,

ICHAR
GO

POSITION

WILL

OPERATIONS

HOME

COPY

AUTOMATIC

PROGRAM,

(ICHAR.EQ.99)

ONE

CURSOR

FORMAT(I2)
IF

THE

AND

THAT

THE

SCREEN,

BUILT

RIGHT,

(0,0)

SCREEN,

YOUR

THE

AND

CURSOR

THAT

SCREEN,

13,

INTEGER

VTS55

CAN

INTEGER

THE

ARE

VTS5,

CALL

YOU

ICMD

PLOTS55

RESULT,

THE

INTEGERS

TWO=DIGIT

KEYBOARD

WILL

AND,

USE

SEQUENCES"

THE

CALl,

DEMONSTRATES
"ESCAPE

IN,

CURSOR,

CHAPTER 3

BASIC-PLUS PROGRAMMING

Four BASIC-PLUS functions exist to aid VTS5 graphic programming. The names and purposes of the
functions are as follows:

FNVS, for the display of graphs, markers, vectors, vertical or horizontal lines, and shaded
graphs;

FNV6, for the display of alphanumeric characters on the screen;

FNV7, for the initialization of the screen; and
FNVS, for the display of special "step" histograms.
Each of the functions is used in the form:

D= FNVx(arguments)
where X is the function number and arguments are the integers or character strings you supply in a particular call. After a line containing one of these functions is executed, D will equal zero if the function executed

correctly. If some error is detected in the function, control is immediately returned to the calling program
in most cases, and D is set to -1. D is therefore a kind of "condition code" that can be examined after a

function call to ensure that no errors have occurred.

The BASIC-PLUS definitions for these four functions are contained in the file VT55.BAS.

The function definitions in VT55.BAS must be added to every BASIC-PLUS program you write for the
VT55. The following dialog shows how to add the definitions to your program (the underlined statements

are the ones that you would type).
READY

(The numbered lines for your program.)

APPEND VT55 <CR >

(The function definitions are added to your program.)

BASIC-PL US Programming

READY

RUN or RUNNH <CR >

(The program will be executed.)

Notice that there is no line number for the APPEND statement.
This procedure will add the lines in VT55.BAS to the end of your program, so that it will now contain both
the function definitions and an END statement. Be sure to observe the following rules:

Putan END statement with line number 32767 at the end of each program.

The file VT55.BAS contains BASIC-PLUS statements with line numbers from 20000 to 29999.
Avoid using these line numbers in your program.

Similarly, the function definitions use the following "internal" variables to store graphic information, so they should not be used as variables in your main program:

C9%: Channel number for terminal.

C8$:

Output buffer for alphanumeric text.

C7%: Current graph number.

07%: X value of origin.
Q7%: Y value of origin.

O6%: Enable/disable memory.
Q6%: Enable/disable memory.

The following variables will be destroyed by the functions in VT55.BAS. Do not use them in your

program if they should be unchanged after a call to one of the functions:
C9%:

Output string for FNV6.

09%, Q9%, 08%, Q8%, 09, Q9, 08, Q8, O7, A2, A7:

Tempo-

rary "scratch" variables.

In addition to VTS55.BAS, a demonstration program, DEMOS5.BAS, has been supplied in your BASIC-

PLUS kit. After you have read and understood this manual, you should run DEMOSS (preferably after listing the program on a line printer) so that you can observe the functions in operation:

READY

OLD DEMOS5 <CR>
READY

APPEND VT55 <CR>
READY

RUNNH <CR>
NOTE

See the introduction to Appendix C for instructions on loading
VTS5.BAS from the distribution medium to your system disk.

BASIC-PL US Programming

3.1

FNVS, THE GENERAL GRAPHIC FUNCTION

Basic Call Format; D = FNV5(A1%,A2%,A3%)
A1% can be any integer from 0% to 13% except 12%. The number you insert in place of A1% will select the
procedure to be performed by the FNVS call. The allowable values for A2% and A3% are explained later

for each procedure. An error return (with D = -1) will result if A1% is less than 0%.
3.1.1

Opening and Closing a VTS5 for Output

Call Format: D = FNV5(0%,A2%,A3%)
A2%, an integer from 0% to 63%, is the terminal number of the VTS5 terminal. If the VTSS terminal is
designated "KB1:", for example, then A2% would be 1%. Any time you make A2% greater than 0% in this
manner, the VT55 will be opened for output from your BASIC-PLUS program.

Note that A2% is the number of the VTS5, which is not necessarily the same as the number of the terminal

used to command RSTS/E (that is, the terminal with which you logged on to the system). In fact, if convenient you should log on to a terminal that is not a VTS5, with the VT55 screen in plain view. If you log on
to KB1: and the VTS5 is KB2:, A2% should be 2% when you run the program. Now the VT5S5 will only

display output from the special functions FNVS, FNV6, FNV7 and FNVS8, which are discussed in this
chapter. All other program output, such as the question marks created by INPUT statements, will appear
on your "command terminal,” KB1:. Therefore the VTS5 screen, and any reproduction you make of the

screen, will be free of unwanted messages.

A 3% is the logical unit number opened for the terminal and can be any integer from 1% to 12%. As long as
the VTS5 is open, the logical unit number (or "channel”) specified by A3% will be used for your program’s
output.

To close the terminal just call FN'VS5 again, but this time make A2% a negative integer (any negative value

will work). You should always enter a 0% for A3% in a closing call, for example:
D = FNV5(0%,-5%,0%)
This call would close the terminal, closing whatever logical unit number was opened by the previous command opening the terminal. Closing your VTS5 terminal also erases any graphic figure on the screen, dis-

ables the graphic features you have chosen, and resets the starting coordinates (see A1% = 7) to (0,0).
Therefore, the best practice in VTS5 graphic programming is to make the opening call (A2% > 0%) the

first FNVS call and the closing procedure the last call in your program.
NOTE

Any alphanumeric text that was displayed by your program
will remain on the screen whether or not you close the VT55.

If you enter a logical unit number outside the range 1%-12% or
a terminal number outside the range 0%-63%, an error return

will result (D= -1).
3.1.2

Graphic Display with FNVS5

There are eight forms of FNVS that control graphic displays, the forms being selected by your choice of
AT1%. Pay particular attention to the order in which graphic commands are given, as illustrated in the exam-

ples that accompany the command descriptions.

3-3

BASIC-PL US Programming

Select Graph Number (A1% = 1%)

Call Format: D = FNV5(1%,A2%,0%)
A2% should either be 0% or 1% and will select the graph number for the next regular or shaded graph to be
plotted. This number will serve as the "label" for the figure as long as the figure is enabled. A3% is always

0% in this call. Note that selecting this graph number is only a labeling procedure (that is, it selects a regis-

ter to contain the graph plotting values) and does not display a graph. Displaying a graphic figure is a threestep process:

Enable the figure (A1% = 2%).

Select graph number (A1% = 1%).

Plot the figure (A1% = 3%).

Enable or Disable Graphic Figures (A1% = 2%)

Call Format: D =FNV5(2%,A2%,A3%)
This command is the "fundamental” form of

FNVS$, because all the graphic figures must be enabled before

they will appear on the VT35 screen. These figures are all disabled at first, and once enabled they will remain so until specifically disabled.

A2% and A3% tell which figures will be enabled or disabled, respectively. The following numbers can be

used for either A2% or A3%:

= Enter (or leave) graphic mode.

= Enable (disable) Graph 0.

= Enable (disable) Graph 1.
= Enable (disable) Shaded Graph 0.
= Enable (disable) Shaded Graph 1.

8%
16%
32%

64%
128%

= Enable (disable) horizontal lines.
= Enable (disable) vertical lines.

256%

= Enable (disable) markers on Graph or Histogram 0.
= Enable (disable) markers on Graph or Histogram 1.

512%

= Disable all figures and clear the graphic memory (A2% only).

When you are enabling and disabling figures, you can either put single integers in the call for A2% and
A3%, or you can substitute expressions that combine any or all of the figures. For example,

D =FNV5(2%,1%+2%+512%,8%)
would do the following procedures:

Erase any graphic figures left on the screen by previous programs (512%);

Enter graphic mode and enable Graph 0 (1%+2%); and

Disable Shaded Graph 0 (A3% = 8%).

3-4

BASIC-PLUS Programming

NOTES

[f you enter the same number for A2% and A3%,
the corresponding graphic figure will be enabled.

Instead of an expression like 1%+2%, you can enter
the sum of several numbers to enable or disable figures, such as 24% to refer to both Shaded Graph 0

and Shaded Graph 1. However, the expression form
will be more readily understood by other persons
reading your program.

It is a good practice to always include the number

512% in the A2% position the first time you enable
graphic figures. Doing so will eliminate graphic dis-

plays left on the screen by a previous program.
4.

It is usually undesirable to enable a graph and a

shaded graph with the same graph number (e.g.,
Graph 0 and Shaded Graph 0).

An error return will occur (with D set to -1) if the
sums of the arguments are outside the range 0%-

1023% (fOI' A2%) or 0%-511% (fOI‘ A3%).
Plot Graph (A1% = 3%)

Call Formats:

D =FNV5(3%,A2%,A3%)
or

D = FNVS5(3%,A2%,0%)
The first call format shown is used to plot a single point at the coordinates given by A2% (0% to 511%) and

A3% (0% to 235%). For example,
850

FOR 1% = 1% TO 511%

860

D =FNV5(3%,1%,235%*RND)

870

NEXT I%

will plot points on the screen with x values from 1to 511 and with y varying randomly between 0 and 235.

The second format plots points with y values from an array called V5. You must dimension V5 and fill it
with y values before trying to plot the graphic figure. V5 must be dimensioned to at least -A2%-1%. Other-

wise, the FNV5 call will cause a fatal subscript error. Remember that BASIC-PLUS arrays begin with a
zero subscript, so that the statement DIM V5(511) creates a 512-element array. For example,

340

DIMENSION V5(511)

350

FOR I% =0%TO 511%

360

V5(1%) = 118%+100%*SIN (1%/50.)

370

NEXT I%

380

D =FNV5(1%,0%,0%)

390
400

D =FNVS5 (20/0,10/0+2%,00/o)
D =FNV5(3%,-512%,0%)

3-5

BASIC-PL US Programming

Lines 340-370set up V5 as a 512-element array and then fill up V5 with sine values.
Line 380 selects 0 as the label of the next graphic figure. Line 390 enters graphic mode and enables Graph

Line 400 now plots the sine function in the form of a graph (Graph 0). Notice that A2% is a negative integer. When A2% is negative, FNV35 plots a number of y values from V5 equal to the absolute value of A2%.

In the example shown here, 512 values (the entire contents of V5) will be used, so the sine function will
extend over the entire width of the screen.
NOTE

An error return (D = -1) will occur if A2% is ever less than -512% (for the
second format). D is also set to -1 if you plot a point with coordinates outside
the screen area (A2% < 0%, A3% < 0%, A2% > 511%, or A3% > 235%).

Example 1

'THIS

SAMPLE

BASIC=PLUS

PROGRAM

USES

THE

PLOT

'FOUR FUNCTION STATEMENTS NEEDED
! GRAPHS AND SHADED GRAPHS.,
/

'BEGIN BY CREATING THREE ARRAYS; Al1%$ WILL BE
!THE SINE FUNCTION, A2% THE COSINE FUNCTION
'AND A3% THE EXPONENTIAL FUNCTION,
4

100
110
120
130
140
150
160
170
180
190

DIM
FOR

A1%(499),A2%(499),A3%(499),V5(499)
I% = 0% TO 499%
F1=I%/50,
[1=P1*F1
A1%(I%) = SIN(T1)*¥100+100
A2%(I%) = COS(T1)*100+100
A3%(I%)=EXP(F1)
NEXT I%
INPUT "WHAT 1S THE VIS5’S KEYBOARD NUMBER";T%
D = FNV5(0%,T%,1%)
I"CHANNEL
1" ATTACHED.,
|

'DEFINE STARTING POSITION, SELECT
'AND PLOT THE SINE FUNCTION.

GRAPH

200
210

D = FNV5(7%,0%,0%)
!'START
D = FNV5(2%,1%+2%,0%)
'ENABLE GRAPHIC MJDE AND
!GRAPH O,

220

240

250

INPUT "CONTINUE";CS
!PAUSE AND WAIT FOR TARRIAGE RETURN; THEN
'PUT THE CUSINE FUNCTION ON THE SCREEN, TOO.

230

FNV5(1%,0%,0%)

V5 (I%$S=A1%(I%)

FOR I%=0%

'VS

SINE

NJWN

THE

!SELECT

TO 499%

FUNCTION,

FNV5(3%,~500%,0%)

X=0.

GRAPH
0,

!PLOT THE SINE

3-6

GRAPH.,

BASIC-PL US Programming

260
270
280
290
300

D
D

=
=

FNV5(2%04%10%)
FNV5(1%,1%,0%)

VS (I%)=A2%(I1%)

FOR

I%=0%

'CHANGE V5 TO COSINE,
D = FNV5(3%,=-500%,0%)
INPUT "CIONTINUE";C

lENABLE
!SELECT

TO 499%

!PLOT

GRAPH
GRAPH

THE

1.
1.

TOSINE

GRAPH,

310

o=
O o=

ERASE BJIH
\PREPARE TO
=

FNV5(2%,8%+16%,2%+4%)

SHADED
!SHADED

GRAPH
GRAPH

320

330

VS(1%)=A3%(1I%)

340

350
360
370
380
390
400
410

GRAPHS (BY DISABLING THEM) AND
DISPLAY SHADED GRAPHS INSTEAD,

0
1

WILL
WILL

BE
BE

THE
THE

FNV5(1%,0%,0%)
FOR

EXPONENTIAL
COSINE,

SELECT
I%=0%

SHADED

AND

GRAPH

0.,

499%

VS = EXPONENTIAL,
D = FNV5(3%,-500%,0%)
!PLOT THE EXPONENTIAL.,
D = FNV5(1%,1%,0%)
!SELECT SHADED GRAPH 1.
VS (I%)=A2%(1%) FOR 1%=0% ID 499%

INOW V5 = COSINE,
D = FNV5(3%,-500%,0%)
INPUT "CONTINUE";CS
D = FNV5(2%,0%,16%)
INPUT "CONTINUE";C
D = FNV5(2%,2%,8%)

'ENABLED GRAPH 0
IDISABLED SHADED
420

32767

END

!PLOT

THE

'ERASE

THE

'CHANGE

AND
GRAPH

COSINE,
COJSINE

SHADED

EXPONENTIAL

GRAPH,

FNV5(0%,-1%,0%)

'CLOSE

CHANNZL

Plot Horizontal Line (A1% = 4%)

Call Format:

D=FNV5(4%,A2%,A3%)

A3% gives the y coordinate (0%-235%) ofthe horizontal line.
A2% is either 0% or 1%. A2% = 0% will erase the line at the y position given by A3%. A2% = 1% will display
the line.

Remember that the horizontal line feature must have been enabled previously by a call such as

D = FNVS5(2%,1%+32%,0%)
NOTE

An error return will occur if you try to display a line

off the screen (A3% < 0% or A3% > 235%) or if
A2% is any number other than 0% or 1%.

3-7

BASIC-PL US Programming

Plot Vertical Line (A1% = 5%)

Call Format:

D =FNV5(5%,A2%,A3%)

This command is very similar to A1% = 4%, but it uses a different combination of arguments to plot vertical lines instead of horizontal lines.
In this call A2% is the x coordinate at which a vertical line will either be displayed or erased. A2% can take
values between 0% and 511%.

A3% = 0% will erase the line and A3% = 1% will display the line.
Again, any values entered for A2% or A3% that are not within the legal range will cause an error return.
Example 2:

20
30

!THIS

PROGRAM

!THE

VERTICAL

DRAWS

AND

"GRID"

HORIZONTAL

MEMORY

CLEARED;

GRAPHIC

!BOTH LINE TYPES ENABLED.
FOR 1%=2% TO 502% STEP 10%
D = FNV5(5%,1%,1%)

!51

70
80

LINES

ARE

THE

INPUT "CONTINUE";CS
!TYPE A CARRIAGE RETURN TO
FOR I1%=2% TO 232% STEP 10%
D
NEXT

124

WITH

MODE

AND

SCREEN;

PAUSE,

CONTINUE.

FNV5(4%,1%,1%)

HORIZONTAL

LINES

ADDED,

110
120
130

INPUT "CONTINUE";CS
FOR I%=2% TO 502% STEP 10%
D = FNV5(5%,1%,0%)

140

150

!VERTICAL LINES ERASED,
D = FNV5(0%,=1%,0%)
END

32767

SCREEN

FIGURES,

VERTICAL

100

THE

LINE

INPUT "WHAT IS THE VTS55'S TERMINAL NUMBER":;T%
D = FNV5(0%,T%,1%)
!O0PEN AS CHANNEL
D = FNV5(2%,1%+512%+32%+64%,0%)
{GRAPHIC

!CLOSE

CHANNEL

Plot Markers (A1% = 6%)

Call Format:

D =FNV5(6%,A2%,A3%)

This command will display or erase markers on regular and shaded graphs plotted with Al% = 3"/«3. The
markers are short vertical line segments that will appear on the graph at the x position you specify in the
call.

A2% is the x position of the marker (0%-511%).
A3% = 0% will erase the marker, and A3% = 1% will display it.

3-8

BASIC-PL US Programming

NOTE
This command will not work properly unless A2%
and A3% are within the stated ranges.

Example 3:

ITHIS

PROGRAM

{GRAPHS

DEMONSTRATES

THE

USE

OF MARKERS
ON

AND HISTOGRAMS,

100
110
120
130

DIM V5(499)
INPUT "WHAT IS THE VTS5’S TERMINAL NUMBER";T%
D = FNV5(0%,T%,1%)
{JPEN FOR OUTPUT AS CTHANNEL
VO(I%)sSIN(PI*1%/50,)*%100,+4100, FOR I%=0% TO 499%

{V5

NOW

140

FNVS(2%,1%+512%+2%+128%,0%)

CONTAINS

SINE VALUES,

{RESET THE GRAPHIC MEMORY AND
lENABLE GRAPHIC -MODE, GRAPH 0,

AND

MARKERS

150
160
170

FNV5(7%,0%,0%)

!START

D
D

=
=

FNV5(1%,0%,0%)
FNV5(3%,=500%,0%)

ISELECT

180

INPUT

190
200
210

FOR I%

220
230

260
32767

!PLOT

FJOR

GRAPH

THE

GRAPH

X=0.,
0,

SINE

GRAPH.

"CONTINUE";CsS

{PUT

50%

MARKER

500%

STEP

THE

GRAPH

50%

EVERY

INPUT "CONTINUE";CS
D = FNVS5(2%,8%,2%)

IENABLE SHADED
!DISABLE GRAPH
240
250

GRAPH
0,

UNITS,

{PAUSE,
!CHANGE

SINE

SHADED

GRAPH.

INPUT "CONTINUE";CS
= FNV5(2%,0%,128%)

IPAUSE,

{REMOVE THE MARKERS,
gN; FNVS5(0%,-1%,0%)

BUT

LEAVE

THE SHADED GRAPH,
!CLOSE THANNEL 1,

Define Starting Coordinates (A1% = 7%)

Call Format: FNV5(7%,A2%,A3%)

This command defines new starting coordinates for vectors, graphs, and shaded graphs. For regular and
shaded graphs, the Define Starting Coordinates command supplies a starting x coordinate for the figure,
without affecting the starting y coordinate. This command has no effect on single points plotted with A1%
= 3%).
NOTE

An error return will occur unless A2% is in the
range 0%-511% and A3% is in the range 0%-235%.
Draw Vector (A1% = 8%)

Call Format;:

D = FNV5(8%,A2%,A3%)

BASIC-PL US Programming

This command draws line segments called vectors, which extend from the starting coordinates to a point
on the screen given by A2% and A3%.

A2% is the x coordinate of the vector’s destination point and should be a number from 0% to 511%. A3% is
the destination y coordinate, with allowable values between 0% and 235%. (An error return will occur if
A2% or A3% is outside its legal range.)
If you have previously defined starting coordinates (A1% = 7%) when you draw a vector, the vector will

begin at those coordinates. Remember that the "initialization" function FNV7 (described later) resets the
starting coordinates to (0,0).
The Draw Vector command itself also resets the starting coordinates to those of the destination point sup-

plied in your call. This feature allows you to "chain" vectors together to form geometric figures or other
straight-line drawings. If you want to draw a series of vectors that originate at the same point, you can simply interweave Define Starting Coordinates commands with your Draw Vector commands.
Vectors are not graphic figures, strictly speaking, because they do not have to be enabled. However, you

can (and should) label a series of vectors that make a design as Graph 0 or Graph 1, and Graphs O and 1 do,
of course, have to be enabled. Remember that you cannot draw a vector that is perfectly vertical.
Example 4:

ITHIS SAMPLE PROGRAM DEMONSTRATES THE USE
'!OF VECTORS, WHICH CAN BE USED TO DRAW
|GEOMETRIC FIGURES (A DIAMOND 1IN THIS CASE)
!AND CAN BE LABELED LIKE GRAPHS,
|

100

INPUT "WHAT IS THE VTS55’S TERMINAL NUMBER";T%

110

D = FNV5(0%,T%,1%)

'OPEN "CHANNEL 1."

130

D = FNV5(1%,0%,0%)

!SELECT GRAPH O.

120

140

D = FNV5(2%,1%+512%+2%+4%,0%)
ICLEAR THE SCREEN OF GRAPHIC DISPLAYS, ENTER
'GRAPHIC MODE, AND ENABLE BOTH GRAPHS.
D = FNVS5(7%,100%,100%)

150
160
170

1(100,100) 1S THE STARTING POINT OF THE FIRST VECTOR,
'!FIRST VECTOR,
D = FNVS5(8%,150%,150%)
!SECIND VEZTOR,
D = FNV5(8%,200%,200%)
'SELECT GRAPH 1.
D = FNV5(1%,1%,0%)

180

D = FNV5(8%,150%,50%)

200

'THE DIAMOND 1S COMPLETE,
INPUT "CIONTINUE";CS
ITYPE A CARRIAGE RETURN IJ CONTINUE,

190

' THE BOTIOM OF THE DIAMOND WILL BE GRAPH 1.

'THIRD VECTOR,

'FOURTH (FINAL) VECTOR.

D = FNV5(8%,200%,100%)

210

D = FNVS(2%,0%,4%)

'!DISABLE GRAPH 1.

220

D = FNV5(0%,=1%,0%)

'!“LOSE CHANNEL 1.

32767

I TO DEMONSTRATE THE FACT THAT TWJ SEPARATE
I"GRAPHS" ARE BEING DISPLAYED, GRAPH
11 (THE BOTTOM OF THE DIAMOND) wAS ERASED,

END

3-10

BASIC-PL US Programming

3.1.3

Alphanumeric Display with FNVS

The actual output of alphanumeric characters to the VT55 screen is done with a separate function, FNV6.
However, FNV5 contains three command forms that are useful for alphanumeric display programming.

Position Cursor (A1% = 9%)

Call Format:

D =FNV5(9%,A2%,A3%)

This command positions the cursor at a new point whose coordinates are given by A2% and A3%.
A2% is the number of character positions from the left edge of the screen at which the cursor will appear.
A2% can therefore take values from 0% to 79%.
A3% is the number of lines from the top of the screen at which the cursor will appear. Since there are 24
lines per screen, A3% can be any integer from 0% to 23%.

Note that an error return (D = -1) will occur if you enter values for A2% or A3% that exceed the legal
ranges.

Note also that moving the cursor with this command has no effect on graphic or alphanumeric displays on

the screen.

Erase from Cursor to End of Screen (A1% = 10%)

Call Format:

D= FNV5(10%,0%,0%)

This command erases all alphanumeric text from the screen, starting at the cursor position and continuing
to the bottom of the screen.

This command does not erase graphic figures from the screen, nor does it change the cursor position.

Notice that the call format is completely standard for this command; the arguments are always 10%, 0%,
and 0%.

Erase from Cursor to End of Line (A1% = 11%)

Call Format:

D =FNV5(11%,0%,0%)

This command is very similar to A1% = 10%, the difference being that the erasure stops at the end of the

cursor’s line instead of continuing to the end ofthe screen.
Note again that the format is constant.
As with the previous command, the status of graphic figures and the cursor position are unaffected by the
erasure.

3.1.4

Producing Hard Copy with FNVS

FNV5 can be used to send special instructions called "escape sequences" to the VTS5 terminal. An escape
sequence consists of the ASCII code 155, which is interpreted as an <ESC> character in RSTS/E, and a

value you supply as A2% in the following call:

D =FNV5(13%,A2%,0%)

3-11

BASIC-PL US Programming

As is discussed in the VT55-E,F DECgraphic Scope User’s Manual, escape sequences can be used to perform a variety of functions, including "cursor control" and screen erasure. Of course, these two types of
control are provided by forms of the FNVS function, so that there is no advantage to using escape sequences.

The most helpful application of escape sequences is in producing a paper copy of the screen display. This
procedure is only valid for VTS5 terminals with a built-in hard copy unit; the same program can be run on

a terminal with no hard copier, but the hard copy commands (93%-95%) will be ignored.
Following is a list of values for A2% that will perform hard copy operations:

A2% Value

Procedure

91%

Hold screen.

92%

Release screen.

93%

Copy from top of screen to cursor.

94%

Start automatic copying.

95%

Stop automatic copying.

The following example would copy all graphic and alphanumeric displays from the screen:
100
110
120

130

D
D
D
D

= FNV5(9%,79%,23%)
= FNV5(13%,91%,0%)
= FNVS5(13%,93%,0%)
= FNV5(13%,92%,0%)

'Cursor to bottom right.
'Hold screen.
'Copy entire screen.
'Release screen.

As shown in Line 100, you have to first move the cursor to the bottom right corner of the
screen, because the copy operation will stop when the cursor is reached.

Line 110 will "hold" the screen, temporarily preventing the display of further text or graphic
figures. While the VTS5 is in this mode, the computer will still read characters typed on the
keyboard, but will not "echo" them, so they will not appear on the screen.
Line 120 now copies everything on the screen, from the topmost line to the cursor.

Now that the copy operation is finished, the screen is released by Line 130, which cancels the
previous Hold Screen command. After the screen is released, you will have to press the

SCROLL key a few times before you can continue. The SCROLL key will display any messages that were received while the screen was still being held, for instance, the READY message that tells you the system is ready for new commands.
If you have a screen display consisting entirely of alphanumeric text, you can use the automatic copy com-

mands to produce "line printer" type listings. When the VTS55 is in automatic copy mode, it will first copy

everything up to but not including the line containing the cursor; then it will copy one additional line each

time you push the <LINE FEED> key on the keyboard. The following example shows a programmed
automatic copy operation;:

100
110
120

130

D = FNV5(9%,0%,0%)
D = FNV5(13%,91%,0%)
D = FNV5(13%,93%,0%)
INPUT A$

'Cursor to home position.
'Hold screen.
IStart automatic copying.

'A LINE FEED WILL COPY ONE MORE
'LINE. THE LETTER ’S’ WILL STOP
'AUTOMATIC COPYING.

3-12

BASIC-PL US Programming

140
150
160

IF A$="S’ GOTO 160
GOTO 130
D = FNV5(13%,95%,0%)

'Type S to stop.
'Read the next character.

IStop automatic copy.

This example will read each line feed that you enter to copy lines. It will keep the terminal in
automatic copy mode until you enter the character S.

NOTES
1.

Automatic copying should only be used

with alphanumeric text. The hard copy of a

graphic figure will be distorted if produced
in line-by-line fashion.
2.

The screen will temporarily go blank while a
COopy operation iS in progress.

The copy operation can be manually started
any time the program pauses by simply
pressing the orange COPY key on the VTS5
keyboard. Similarly, pressing the COPY key
while holding down the SHIFT key will

both start and stop automatic copying.

3.2

FNV6, THE TEXT OUTPUT FUNCTION

Call Format:

D =FNV6(N%,C19)

FNV6 displays a character string on the VT55 screen. The string will appear with the first character at the
cursor position, so that

FNV6 is often used in combination with the "alphanumeric" forms of FNV35, which

control the cursor position and the erasure of characters (see Section 3.1.3).
As the format shows, there are only two arguments for

FNV6, both of which are required at all times.

C18$, a string variable, stores the text that you wish to display on the screen. C1$ can be either a regular or
subscripted variable, depending on the type of display you are designing. A regular string variable can accept a string of 80 characters, which is the maximum width of a line of characters on the screen. Therefore,
you can use regular variables when the string will be displayed horizontally. Vertical displays require ei-

ther subscripted variables, so that one element can be displayed per line, or alternatively, the use of the

BASIC-PLUS function MID, which selects "substrings" from a regular character string variable and thereby allows you to address individual characters or groups of characters in a string. Example 5 shows how
MID can be used to put a vertical label on a graph.

3.3

FNV7, THE INITIALIZATION FUNCTION

Call Format:

D=FNV7

This simple function (notice that there are no arguments) resets the screen to an "initial state," that is:
1.

The starting coordinates are reset to the point (0,0), the lower left corner of the screen;

All graphic figures are erased from the screen, leaving only alphanumeric text;

3-13

BASIC-PL US Programming

The internal variables O6% and Q6%, which store information about the graphic figures, are reset
to 0, disabling all graphic figures; and

The terminal is returned to alphanumeric mode.

All four ofthese initializations can, of course, be performed by FNVS5 calls, but FNV7 is a more direct and

simple method. Therefore, it is good practice to call FNV7 immediately after opening the terminal (see
Example 5).

NOTE

FNV7 should not be used in the middle of a
program unless you want to totally eliminate the effects of previous FNV
35 calls.
Example 5:

!THIS

SAMPLE

PROGRAM

USES

SEVERAIL

FORMS

FNVS

100
110
120

!AS WELL AS THE ALPHANUMERIC FUNCTION FNV6 AND
!THE INITIALIZATION FUNCTION FNV7,
DIM V5(499)
INPUT "WHAT IS THE VTS55'S TERMINAL NUMBER";T%
D = FNV5(0%,T%,1%)
!OPEN "CHANNEL 1."
D = FNV7

130

!FNV7 CLEARS THE SCREEN OF GRAPHIC FIGURES
!RESETS THE STARTING COORDINATES TO (0,0),
GosuB 1000

140

!THE SUBROUTINE AT LINE
!FROM THE SCREEN,
D = FNV5(9%00%012%)

1000

CLEARS

ANY

AND

STRAY

TEXT

)

'PUT

THE CURSOR

'DISPLAY

THE

BEGINNING OF LINE

AND

MESSAGE.

150

C9s='TYPE A CARRIAGE RFTURN;

160
170

D = FNV6(58%,C98)
INPUT "CONTINUE":CS

!DISPLAY THE CHARACTERS,
!PAUSE FOR CARRIAGE RETURN,

SYMBOLS WILL

VANISH:

180
190
200
210

D = FNV5(9%,44%,12%)
D = FNV5(11%,0%,0%)
INPUT "CONTINUE";CS
GOSUB 1000

!REPOSITION CURSOR,
!ERASE SYMBOLS,
!PAUSE,
!CLEAR SCREEN,

LJUSE

FNVe

LABEL .A

GRAPH,

220

D
.= FNV5(2%,1%+2%+32%+64%+128%,0%)

240
250
260

D = FNV5(9%,0%,2%)
INPUT X1$
GOSUB 10006

280
290

D = FNV5(9%,0%,2%)
INPUT Y1$

230

270

'TYPE X

AXIS LABEL

'TYPE Y AXIS LABEL

(UP TO

80 CHARACTERS):'

'POSITION

'CLEAR

CURSOR,

SCREEN,

(UP TO 24 CHARACTERS):'

3-14

1234567890<>+"

BASIC-PL US Programming

300

GOSUB

310

FOR

1%=0%

1000

330

340

FNV5(5%,0%,1%)\D

350

FNV5(9%,0%,23%)

ICURSOR

FNV6(80%,X1$)

!DISPLAY

320

ICLEAR

V5(I%)

360
370
380
390

FOR

400

1%
L2%

SIN(PI*I%/50,)%100.+4100,
=

FNV5(4%,1%,0%)

FNV6(1%,MID(Y1S,I%,1%))

FNV5(1%,0%,0%)

430

D
D

=
=

FNV5(3%,-500%,0%)
FNV5(9%,40%,0%)

INPUT

AXIS

460

!DISPLAY

ROTTOM

LEN(Y1S$)
= I%~1%
FNV5(9%,0%,L2%)

410

450

!L2%

POSITION

FNV5(9%,40%,0%)

UNTIL

DISPLAY

THE

LABEL,

LINE

COUNTER,

CURSOR

FOR

'DISPLAY

ONE

CHARACTER,

AXIS

SINE

LABEL

FUNCTION,

CHARACTER,
COMPLETE,

MARKER";M1%

470

FNV5(11%,0%,0%)

!ERASE

480

THE

FNVS(6%,M1%,1%)

!PUT

MARKER

1000
1010

!THIS SUBROUTINE CLEARS
D = FNV5(9%,0%,0%)

THE SCREEN,
!CURSOR TO HOME

1020

'ERASE

1030

RETURN

32767

END

3.4

AXES.

LINE,

'POSITION

!CONTINUE

!NOW

!VS5=SINE,

420
440

SCREEN,

499%

FNV5(10%,0%,0%)

MESSAGE.

XzM1%,

POSITION,

SCREEN,

FNVS8, THE STEP HISTOGRAM FUNCTION

Call Format:

D = FNV8(N%,0$,Q%)

FNVS8 creates step histograms, or vertical bar graphs, from the array V5. V5 must be properly dimensioned
and filled with values in the main program, and you must select either Shaded Graph 0 or Shaded Graph 1

before the FNV8 call. After these preliminaries, a call to FNV8 has the following results:
1.

The first N% values are selected from V5.

Thescreen width (512 x units) is divided into N% equal-sized segments.

N% horizontal vectors are drawn, each with a width of 512%/N%. The screen area beneath each
vector 1S then shaded to create N% vertical bars.

The horizontal vectors have been enabled separately as Graph 0 (or 1 if you selected that number
before the FNVS8 call). The entire step figure is then enabled as a Shaded Graph with the same
number as the vectors’ graph number. Because of this dual use of the same graph number, the

envelope of the step histogram (that is, the vectors) will have a higher display intensity than the
rest of the figure. As was mentioned previously (Section 3.1.2), the effect of using the same graph
number twice is usually undesirable, although it adds clarity to the final figure in this case.

Thedifferent bars will have heights equal to the corresponding "y values" selected from V5.

3-15

BASIC-PL US Programming

Finally, the character strings you have supplied for O$ and QS are displayed as labels for the hori-

zontal and vertical axes of the histogram, respectively. O$ can be a string of up to 80 characters,
and Q9 as many as 24 characters.
Consider the following calling sequence:

10
20

DIM V5(19)
D =FNV5(1%,0%,0%)

FOR 1% = 0% TO 19%

V5(1%) =10%*(1% + 1%)

NEXT %

D = FNV8(20%, ’FIRST 20 INTEGERS’, INTEGERS TIMES TEN’)

'Select graph number.

'Fill V5 with integers.

This fragment would display twenty bars, each about 25 x units wide (512%/20%). The first bar would be
10 y units tall and the twentieth bar, 200 units.
Besides being a useful function in its own right,

FNV8is a good model for new functions you can create for

your special needs. BASIC-PLUS has easy procedures for writing new functions, and your growing experi-

ence with VTS5 programming will allow you to combine FNVS5, FNV6, FNV7, and FNVS8 to create increasingly powerful graphic commands. Appendix C of this manual suggests other functions that you may
find useful.

3-16

APPENDIX A

FORTRAN (PLOTS5) ASSEMBLY AND LINKING PROCEDURES

PLOTS5S is supplied in both source and object form. If the PLOTSS file in your kit is labeled PLOTS55.MAC,

it is a MACRO-11 source file and must be assembled (Section A.1) and then linked to each program you
write that contains PLOTSS5 calls (Section A.2). If you are given a preassembled object file (PLOTS55.0BJ),
you only have to follow the linking procedures for your operating system.
A.1

ASSEMBLING AN OBJECT FILE

This procedure will translate the MACRO-11 assembly language code in PLOT55.MAC into binary ma-

chine instructions. You must do this job and the linking procedure shown in Section A.2 before your program will work.

Suppose you are using a PDP-11/34 computer with a pushbutton console, two RKO05 disk drives, and the
RT-11 operating system.

Put the DECpack containing PLOTS55.MAC in Disk Drive 1 (DK1:) and close the door. Push the
switch on the disk drive panel from LOAD to RUN.

In the same manner, load your "system disk" into Drive 0 (DKO:). This disk should contain an RT-

11 operating system, the MACRO-11 assembler (MACRO.SAV), and the System MACRO Library
(SYSMAC.SML).
3.

Start the RT-11 system by these procedures:
A.

Push the button marked CTRL on the PDP-11/34 and hold it down while you press the

BOOT button. The terminal will display a list of octal numbers followed by the $ symbol.
B.

Type the two-letter device code on the terminal that represents the storage device containing
your system. Because we are using RKO0S disks in our example, you would type the underlined symbols:

077776.

012456. 127645

$DK <CR>
C.

The computer will read the bootstrap from your system in Drive 0, start the RT-11 system,
and display the system title, for example:

RT-11 F/B V02C

Then the system will display a period (.) at the left margin, meaning that it is ready to accept
system commands.

A-1

FORTRAN (PLOT)55) Assembly and Linking Procedures

Assemble the PLOTS55 object file by typing the underlined parts of these lines:

R MACRO <CR
>

*PLOT55=DK 1:PLOT55 <CR
>

"¢
The second asterisk shown above will not appear until the assembly of the object file is complete. To exit

from MACRO, you then type "Control C" by holding down the CTRL key on the terminal while you type a
C. At this point PLOTS55.0BJ has been created on Disk 0. If you want the new object file to be placed on

Disk 1, type DK1:PLOTS5 on both sides of the equal sign rather than only the right side.

If you are using a different computer:
Follow the customary procedures for bootstrapping the system and then begin with Step 4 of
the previous assembly procedure.

[f you are using an RSX-11 system:

When your PLOTS5 source is on a DECtape (DT:) or RK disk (DK:):

>MOU DK:(or DT:)PLOT55 <CR
>
>MAC PLOT55=DK:(or DT:)[200,200]PLOTSS <CR >
When your source is on magnetic tape:

>FLX SY:/RS=MT: (or MM:) [200,200] PLOT55.MAC/DOS <CR
>
>MAC PLOTS55=PLOT55 <CR >
Both procedures will asssmble PLOTSS5.0BJ on the system device, placing the object file in
the UIC under which you have logged on to the system. The additional FLX command is
necessary in the second step because the magnetic tape is in DOS-11 format.

If you are using an [AS system:

When your PLOTS55 source is on a DECtape (DT:) or RK disk (DK:):
PDS>MOUNT <CR
>

DEVICE? DK: (or DT:) <CR
>
VOLUME-ID? PLOT55 <CR
>

PDS>MACRO DK: (or DT:) [200,200]PLOTS5 <CR
>
When your PLOTSS source is on magnetic tape:

PDS>MOUNT/FOREIGN/OVERRIDE:VOLUMEID
<CR >
DEVICE? MT: (or MM:) <CR
>
VOLUME-ID? PLOTS5 <CR
>
PDS>COPY <CR>

FROM? MT: (or MM:) [200,200] PLOT55.MAC/DOS <CR
>
TO? ** <CR
>

PDS>MACRO PLOTS55 <CR
>

After either procedure, the assembled file PLOTS55.0BJ will exist on the system device with
the same UIC under which you logged on to 1AS.

A-2

FORTRAN (PLOTSS5) Assembly and Linking Procedures

If your storage devices are not RK05 disks:
The only change is the two-letter code for the device. Standard codes include:

SY:

Any device identified beforehand as the system device for your installation.

DB:

DX: =

A.2
A.2.1

RP04, RP0S, or RP06 disk drive.
RXO01 "floppy disk" drive.

DT:

DECtape drive.

CT:

DECcassette tape drive (RT-11 only).

DP:

RP02/03 disk drive.

MT: =

TUIO0 magnetic tape drive.

MM:

TJU16 magnetic tape drive.

LINKING AN OBJECT FILE TO YOUR PROGRAM
Procedure for RT-11 Users

Type the underlined parts of the following RT-11 commands:
R LINK <CR >
*program=object,PLOTS5/F <CR >

1€
where "program" is the name you want for the finished program, and "object" is the name of the object file

for that program (that is, the output of the FORTRAN compiler). PLOTSS

is the object file that was either

supplied in your software kit or was produced by the assembly procedure in Section A.l1. The "/F" switch
tells the LINK program that your program is using FORTRAN statements and library functions. LINK

will look for the FORTR
AN library (FORLIB.OBJ) on the system disk. If FORLIB is on some other storage device, follow the PLOTS55 name with ".dc:FORLIB" instead of the /F, where dc: is the code for the
device containing FORLIB.
LINK will print the second asterisk shown to indicate that the linkage was successful. To exit from LINK,
type CTRL C.

Your VTS5 program can now be run by typing
R program <CR >

A.2.2

Procedure for RSX-11 Users

Type the underlined part of the following command in response to the prompt symbol (>):

>TKB task=object/FP,PLOTS55 <CR >
The name you insert for "task" will be assigned to the finished, executable task image of your FORTRAN
program. The label "object" refers to the compiled form of your program, and "PLOTSS5" is actually

PLOTS5.0BJ, the object file that was either supplied in your software kit or created by the assembly procedures in Section A.l1. The /FP switch means that the Floating Point Processor will be used.

Notice that the command line has no references to a FORTR
AN library. The task builder will expect SYS-

LIB to contain the FORTRAN object code needed by your program. If SYSLIB is not on your disk, or if

A-3

FORTRAN (PLOT55) Assembly and Linking Procedures

you are using a separate FORTRAN library, you have to state the exact name and location of the library in
the TKB command, for instance:
>TKB task=object/FP,PLOTS5,DK1:FORLIB/LB <CR >
Regardless of the particular TKB command you use, the prompt symbol will reappear when the task image

is ready. You are then ready to run your VT35 program by typing

>RUN task <CR >
If you received the binary file PLOTS55.0BJ in your kit rather than the source file PLOT55.MAC, you

should transfer the object file to your UIC before running TKB. Use the RSX-11 MOU and FLX commands described in Section A.l. The only change required is making the file name extension .OBJ instead
of MAC.
A.2.3

Procedure for IAS Users

Type the underlined part of the following command in response to the Program Development System’s
prompt symbol:

PDS > LINK/TASK :task object PLOTS5 <CR >
where task is the name you want for the finished, executable task image and object is the name of the file
containing the compiled form of your main program. PLOTS5 represents the file PLOTS55.0BJ, which was
either supplied in your software kit or created by a previous assembly of the file PLOT55.MAC. The PDS
>
prompt symbol will reappear when the task is finished and ready to run. The IAS LINK utility assumes
that the Floating Point Processor will be used.
When the LINK program is finished building the task, the task can be executed with the command

PDS>RUN task

<CR >

If you received the binary file PLOT55.0BJ in your kit rather than the source file PLOT55.MAC, you
should transfer PLOTS55.0BJ to your UIC before running LINK. Use the same IAS MOUNT and COPY
commands described in Section A.1, changing the MAC extension in the COPY command to .OBJ.

A-4

APPENDIX B

SUGGESTED PLOTSS5 APPLICATIONS

This appendix contains examples of FORTRAN subroutines that combine various PLOTSS calls to

achieve "higher level" functions. For example, your use of a VT 55 might require the display of a large number of graphs, in which case you can avoid a large number of PLOTSS calls in your program by following
the techniques suggested in this appendix.

Not all of these routines would be needed by every user, and there is rarely any saving in execution speed,

because the routines result in just about the same number of PLOTS5S calls as would occur anyway. The
advantage of subroutines is that they allow you to define, debug, and save an entire procedure, which can
then be reused as often as necessary without the risk of new programming errors.
You can try the routines suggested in this appendix by compiling and linking them as you did for PLOTSS5.

You may find that they can be used as they are shown here or that some additional modifications would
make them more applicable to your needs.

Notice that these subroutines use the four-argument form of PLOTSS. The fourth argument is the 16-element array ISTAT, and it is placed in a common area labeled STATUS. The use of such a common status
table allows you to share the same status information between any number of routines. Within each routine, individual elements of ISTAT can be examined and changed to control the overall status of the VTS5

display. For example, the element ISTAT(8) stores the current graph number; ISTAT(8) equals 0 if Graph
Ois in use and 8 if Graph 1 is in use. The full list of status table elements and their uses is as follows:

ISTAT(1):
ISTAT(2):

Logical unit number of terminal.
Event flag number to be used.

ISTAT(3):
ISTAT(4):
ISTAT(5):
ISTAT(6):

X value of origin.
Y value of origin.
Work register (do not change contents!).
Work register.

ISTAT(7):

Graphic status (holds the current total from IENAB).

ISTAT(8):
ISTAT(9):
ISTAT(10):

0if Graph Ois in use; 8 if Graph 1.
Graphic mode switch (0=Off, 1=0n).
Work register for vectors (do not change!).

ISTAT(11):
ISTAT(12)-

Character count (RSX-11 only).

ISTAT(16):

B.1

Character output buffer (RSX-11).

INITIALIZATION

In most applications, it is useful to have a routine such as the one shown here that will return the VTS5 to
some initial state as preparation for running a new program.

SUBROUTINE INIT
COMMON/STATUS/ISTAT(16)
DATA ISTAT/16*0/

Suggested PLOTS55 Applications

CALL PLOTS5(13,72,,ISTAT)
CALL PLOTS5(13,74,,ISTAT)

CALL PLOTS5(2,14512,,ISTAT)
RETURN
END

The statement CALL INIT will first clear all alphanumeric text from the screen and then will disable all

graphic figures, clearing the screen of graphic displays as well. INIT is therefore a good example of
a
"starting routine” for a graphic program.

B.2

GRIDS AND COORDINATE AXES

SUBROUTINE GRID(IDX,IDY)

COMMON/STATUS/ISTAT(16)
CALL PLOTS5(2,14324+64,,ISTAT)
DO 1 1=1,512

CALL PLOTS5(5,1-1,0,ISTAT)

CALL PLOTS5(4,0,1-1,ISTAT)

CALL PLOTSS5(S,I-1,1,ISTAT)

CALL PLOTS55(4,1,1-1,ISTAT)

DO 2 1=1,236
DO 31=1,512,IDX
DO 4 1=1,236,IDY
RETURN

END

The numbers you supply for IDX and IDY in a CALL GRID statement will be the spacing in screen units
between the vertical and horizontal lines, respectively. GRID will therefore display a rectangular grid on
the screen, which can be superimposed on other figures such as graphs and histograms. If GRID is called
several times in the same program, it will erase any old grid before displaying a new one.
To display only a y axis at the left edge and an x axis at the bottom of the screen, use a CALL GRID state-

ment with IDX equal to any integer greater than 511 and IDY any integer greater than 235.

The markers described in Chapter 2 (ICMD = 6) are the best way to mark off a graph in the x direction.
You may, however, want to put a vertical scale on a graphic figure as well. With a routine such as GRID,

you could, for example, scale the screen vertically in increments of 20 units by calling GRID with IDX >
511 and IDY = 20.

B.3

GRAPH PLOTTING ROUTINES

The examples in this section suggest "canned" procedures for the most common use of VTS35: plotting
graphs or shaded graphs of already computed data.

SUBROUTINE GRAPH(N,IARRAY)
COMMON/STATUS/ISTAT(16)
DIMENSION IARRAY (512)
NUMBER=ISTAT(8)/8
CALL PLOTS55(7,0,0,ISTAT)
CALL PLOTS5(8,512,0,ISTAT)

CALL PLOTS55(2,1+(NUMBER+1)*2,(NUMBER+1)*10,ISTAT)
CALL PLOTS55(3,-N,JARRAY,ISTAT)
CALL PLOTS55(1,1-NUMBER,,ISTAT)
RETURN
END

Suggested PLOTSS5 Applications

When you write a CALL GRAPH statement, a graph will appear that displays the first N points from IAR-

RAY (where IARRAY is some integer array that you have filled with the points you want to display).
This particular GRAPH routine also switches automatically between Graph 0 and Graph 1, in the following manner:

Aftera CALL INIT statement, CALL GRAPH will use Graph 0 to plot the array you supply.

If GRAPH is called a second time in the same program (without calling INIT again), the second
graph will appear as Graph 1, superimposed on Graph 0.

If GRAPH is called a third time, the new graph will be Graph 0 again, erasing the old Graph 0 but
leaving Graph 1 on the screen. The erasure of the old graph is done by drawing a vector from the

point (0,0) to the point (512,0), which is a short method for resetting all the y values of a graph to 0.
4.

Consequently, all even-numbered calls to

GR APH will create a new Graph 1, and odd-numbered

calls anew Graph 0.

SUBROUTINE SHADOW

COMMON/STATUS/ISTAT(16)
NUMBER=ISTAT(8)/8
CALL PLOTS5(2,1+(1-NUMBER)*8+8,(1-NUMBER)*2+2,ISTAT)
RETURN
END

CALL SHADOW converts a regular graph to a shaded graph.
If you want to "shade" a particular graph, you must call SHADOW immediately after calling

GR APH, for

example,

CALL GRAPH(500,SINE)
[Plot the sine function on Graph 0.]

CALL SHADOW [Shade Graph 0.]
CALL GRAPH(500,COSINE) [Graph 1.]
CALLSHADOW [Shade Graph 1.]

Shading is a useful practice for distinguishing two graphs. For example, the sine and cosine graphs have
exactly the same shape, and so are much easier to tell apart if one of them is shaded.

SUBROUTINE BARS(N,JARRAY)
COMMON/STATUS/ISTAT(16)
DIMENSION IBAR(236,2),JARRAY(512)
NUMBER=ISTAT(8)/8
CALL PLOTS5(7,0,0,ISTAT)
CALL PLOTS55(8,512,0,ISTAT)
CALL PLOTS55(2,1+(NUMBER+1)*2,ISTAT)
WIDTH=512./FLOAT(N)
DO 1I=I,N

IBAR(I,1)=I*WIDTH
IBAR(L,2)=IARRAY(I)
CALL PLOTS5(7,0,IBAR(1,2),ISTAT)
DO 2 [=I,N

B-3

Suggested PLOTS55 Applications

CALL PLOTS55(8,IBAR(1,1),IBAR(I,2),ISTAT)

CALL PLOTSS5(7,IBAR(1,1),IBAR(I+1,2),ISTAT)

CALL PLOTS5(1,1-NUMBER,,ISTAT)
CALL SHADOW
RETURN
END

BARS creates a special type of shaded graph called a step histogram, or "bar graph." BARS will display N

vertical shaded bars of width 512/N on the screen. The bars will have heights equal to the first N elements
of IARRAY. This example of a bar graph routine has the same mechanisms as the previous GRAPH rou-

tine for switching between Graph 0 and Graph 1 and for erasing old graphs (the "zeroing vector").

B.4

LABELING A GRAPHIC DISPLAY

SUBROUTINE LABEL(IXLABL,IYLABL)
COMMON/STATUS/ISTAT(16)
LOGICAL*1 IYLABL(24)
CALL PLOTS55(9,0,23,ISTAT)
CALL PLOT55(12,,IXLABL,ISTAT)
DO 31=1,24

IF(IYLABL(I).EQ.0) GO TO 4
CALL PLOT55(9,0,1-1,ISTAT)
CALL PLOT55(12,1,IYLABL(I),ISTAT)
CALL PLOTS55(9,0,23,ISTAT)
CALL PLOTS55(13,91,,ISTAT)

PAUSE

CALL PLOTS55(13,92,,ISTAT)
RETURN
END

LABEL will use the two strings you enter for IXLABL and IYLABL as axis labels for the x and y axes,

respectively. Note that the labels you supply must be enclosed in single quotation marks (’) to identify
them as alphanumeric strings in FORTR
AN symbology.

The x axis label will appear on the very bottom line of the screen, below the x axis. It can be up to 80

characters long (including spaces).
The y axis label will read from top to bottom (one letter per line) and will appear in "Column 0," the left-

most column of the screen. This column is to the left of a vertical line at x = 0, because the graph area of
the VTS5 is slightly smaller than the alphanumeric area. The y axis label can be up to 24 characters long,
including spaces.

Notice that the LABEL routine sends two escape sequences. The first one holds the screen to prevent the
STOP message from interfering with the display. The screen will not be released until you type a carriage

return (or a "RESUME task" command in RSX-11 systems). If you will be using IAS, replace the PAUSE
statement with the statement pair

READC(5,5)KR
FORMAT(12)

The PAUSE statement will be ignored in an IAS execution. (To bring the terminal back to a completely
normal state after this sort of procedure, press the orange SCROLL key until the STOP message and the
operating system’s prompt symbol reappear.)
B-4

Suggested PLOTS5 Applications

B.S

ATTACHING THE VT55 AS AN OUTPUT DEVICE

The subroutine ATTACH assigns logical unit 1 to the terminal number of the VT55. Then the routine
stores ILUN=1 and IEFN=1 in the status table. This subroutine should precede any other PLOTS55 calls in
a program.

SUBROUTINE ATTACH

COMMON/STATUS/ISTAT(16)
WRITE(S,1)
FORMATCWHAT ISTHE VT55 TERMINAL NUMBER?’)
READ(S,2) NR
FORMAT(02)
CALL ASNLUN(1,TT’,NR)
CALL PLOTS55(0,1,1,ISTAT)
RETURN

END
When you use this routine or any other that attaches the VT55, remember to detach the VTS5 at the end of
the program.

CALL PLOTS5(0,-1,0,ISTAT)
END

NOTE
ATTACH will only work with IAS or RSX-11 systems.

B-5

APPENDIX C

SUGGESTED BASIC-PLUS APPLICATIONS

Chapter 3 suggested that you may want to design some BASIC-PLUS functions of your own, using the four

functions supplied in your kit (FNVS, FNV6, FNV7, and FNV8) as building blocks. This appendix gives
you a few samples that show the four functions as they might be combined to yield even higher-level, and
therefore simpler, graphic support.
Your VTS5 software kit is supplied either on RKO05 disk, DECtape, or DOS-11 format magnetic tape. Use

the following procedures to write the VT55 software onto your RSTS/E system disk:
For RKO05 disk distribution:

Place the RKO0S5 disk in disk drive 0 (DKO:). Close the door.

Logonto the system and type the following command in response to the READY message:
MOUNT DKO:VTS55 <CR >

(Change the device number to DK1: if you are using drive 1.)
3.

Now use the PIP program to copy the disk:
READY

PIP <CR >

....... (PIP VERSION printed by system)
#SY:VT55.BAS=DKO0:VT55.BAS(200,200) <CR
>
#1Z

READY
DISMOUNT DKO:VT55 <CR >

For DECtape distribution:
The same procedure is used as for RKO0S disks except that the device code, wherever it ap-

pears, should be DTO: (for DECtape drive 0) or DT1: (for drive 1). The MOUNT and
DISMOUNT commands may not be necessary; check with your system manager.
For magnetic tape distribution:
READY

MOUNT MT0: <CR >
READY

Suggested BASIC-PLUS Applications

PIP <CR>

#SY:VT55.BAS=MTO0:[200,200]VT55.BAS/DOS <CR >
#1Z

READY
DISMOUNT MT0:/UNLOAD <CR >

All of these procedures will write the file VT55.BAS onto the system disk under the account that you used
to log on.

C.1

INITIALIZATION

The standard function

FNV7 is called an initialization function because it erases old graphic displays from

the screen and returns the VT55 terminal to its initial state, ready to receive new graphic programming

instructions. What FNV7 does not do, however, is to also clear the screen of the letters and numbers that
make up the alphanumeric part of a display. In other words, FNV7 performs a "single" initialization: the
graphic display is cleared from the screen, but the alphanumeric display remains. FNV7 is thus useful
when you want to change from one graph to the next without changing the labels on the axes. In other

cases you might want to combine the graphic initialization of FNV7 with a second initialization that clears
the alphanumeric information from the screen as well. Consider this example:

15000 DEF FNV9

15010 D =

FNV5(9%,0%,0%)

'Cursor to home position.

15020 D = FNV5(10%,0%,0%)

'Erase screen.

15030 FNEND

FNV9 is a different kind of single initialization; it clears the alphanumeric display from the screen but
leaves the graphic display alone. FNV9 could be used by itself in a program you write, or it could be combined with FNV7 in yet another function that performs a "dual” initialization:
15040 DEF FNV1

15050

D=FNV7

15060

D=FNV9

15070 FNEND

If your graphic programs contained these function definitions, then the statement D = FNV7 would clear
only the graphic display, D = FNV9 would clear only the alphanumeric display, and D = FNV1 would
clear both displays.

C.2

GRIDS AND COORDINATE AXES

16000

DEF FNV2(D1%,D2%)

16010

D = ENV5(2%,1%+32%+64%,0%)

16020

FOR 1% = 1% TO 512%

16030

D = FNV5(5%,1%-1%,0%)

C-2

Suggested BASIC-PL US Applications

16040

NEXT I%

16050

FOR 1% = 1% TO 236%

16060

D = FNV5(4%,0%,1%-1%)

16070

NEXT 1%

16080

FOR I% = 1% TO 512% STEP D1%

16090

D =FNVS5(5%,1%-1%,1%)

17100

NEXT 1%

17110

FOR 1% = 1% TO 236% STEP D2%

17120

D = FNV5(4%,1%,1%-1%)

17130

NEXT I%

17140

FNEND

The statement D = FNV2(10%,20%) would display a rectangular grid on the VT55 screen, with the vertical
grid lines separated by 10 units and the horizontal lines separated by 20 units. This particular definition of
FNV2 is written in such a way that if FNV2 is called several times in the same program, Lines 16020-

16070 will erase the old grid before a new one is displayed. Grid lines help give a graphic display a visual
scale; for example, when you display a graph on the screen, you may want to know where the points x =0,
X = 25, and x = 50 are located and what is the approximate value of the graph at these points. The markers
described in Chapter 3 will mark graphs at chosen x positions, but that feature will not give quite as much

numerical information as you want. As an alternative to actually labeling the screen with numbers, you
could display the graph and then write the statement

D =FNV2(25%,5%)
This statement would cover your graph with a "checkerboard," scaling the graph in both directions. The

second line from the left would mark the position x = 295, the third line, x = 50, and so forth; in the y
direction, you could use the horizontal lines, which would be 5 units apart, to estimate the value of any
point on the graph, with an accuracy of about 2 units.
You could also use FNV?2 to put just two important lines, the x and y axes, on the screen, as follows:

D =FNV2(512%,236%)
If you look back to the definition of

FNV2, you will see that this statement would make FNV2 stop after it

had displayed the first line in each direction, so that you would have a single vertical line at x = 0 (the y

axis) and a single horizontal line at y = 0 (the x axis).
Finally, notice that Line 16010 of the

er type of graphic figure. Because

FNV2 definition enables both line types but does not affect any oth-

FNV2 only affects the display of grid lines, you could display one graph

and change the grid scale as many times as necessary to get the right result.

Suggested BASIC-PL US Applications

C.3

PLOTTING GRAPHS

Because the VTS5) is so often used to display graphs, it is usually convenient to have a separate function
prepared that performs all the necessary initialization, enabling, graph number selection, and display in

one step. The function FNV3, defined below, is suggested for this purpose.

15100

DEF FNV3(N%)

15110

D = FNV5(7%,0%,0%)

15120

D =FNVS5(8%,511%,0%)

15130

D = FNV5(2%,1%+(C7%+1%)*2%,(C7%+1%)*10%)

15140

D = FNV5(3%,-N%,0%)

15150

D = FNV5(1%,1%-C7%,0%)

15160

FNEND

You should take note of the following unusual features of this function definition:
1.

Line 15120 draws a vector from the origin (0,0) to the bottom right corner (511,0). This is one of
the simpler techniques for erasing the previous graph for a particular graph number, since drawing

such a vector fills up the appropriate register of the VT55 graphic memory with 512 points, all of
which have a y value of 0.

Line 15130 uses the variable C7%, which is the internal variable that stores the current graph

number in use (C7% = 0% or 1%). You may recall from the introduction to Chapter 3 that you
should avoid using internal variables in your program. In this case, however, the variable C7% is
used in the program for the same purpose for which it is used internally. You should, of course, use
such internal variables with caution, because changing their numerical values would affect the status of the display.

Line 15140 is simply the standard FNVS5 call for creating a graph from the array V3. In other
words, you should assign the values you want to graph to the array V5 before writing
D=FNV3to
create the graph. Line 15140 will then plot the first N% points from V35, starting with an x position
of 0.

Line 15150 will switch the graphic display from Graph 0 to Graph 1 and back to Graph 0 again
automatically as FNV3 is called several times in the same program. The first time FNV3 is called
from your program, the graph will appear as Graph 0; the second time, as Graph 1; and so forth. If
a very large number of graphs are displayed, just remember that the even-numbered calls will create Graph 1 and the odd-numbered calls will create Graph 0.
C.4

SHADING A GRAPH

This section suggests another function, called FNV4 here, that "shades" a graph, converting it from a normal graph made up of points to a shaded graph.

15170

DEF FNV4

15180

D =FNV5(2%,1%+(1%-C7%)*8%+8%,(1%-C7%)*2%+2%)

15190

FNEND

C-4

Suggested BASIC-PL US Applications

FNV4 uses the variable C7%, the graph number, in the same way as described for FNV
3. FNV4should be
called immediately after displaying the graph that you want to shade, because FNV4 will only shade the
graph with the most recent graph number, for example:

15200

V5(1%)=S1(1%)

FOR 1%=0% TO 511%
ISI CONTAINS SINE VALUES.

15210

D=FNV9

'ERASE SCREEN.

15220

D =FNV3(512%)

'PLOT 512-POINT SINE.

15230

D=FNV4

'SHADE THE SINE GRAPH.

15240

V5(1%)=C1(1%)

FOR [%=0% TO 511%
!C1 CONTAINS COSINE.

15250

D =FNV3(512%)

'PLOT 512-POINT COSINE.

In this example, the sine graph would be shaded, but the cosine graph would remain a standard "pointplot" graph. Shading is very useful in just such a case, because the sine and cosine graphs are identical in

shape and can be hard to tell apart unless one of them is shaded.

C-5

INDEX

Alphanumeric array, 2-14

Alphanumeric mode, 1-1, 1-3
APPEND statement, 3-1
Arrays, 1-3

alphanumeric, 2-14

plotting graphs from, 1-3
ASCII character, 1-1
ASNLUN, 2-2

Assigning logical unit numbers, 2-2

Automatic copying, 2-18, 3-12
Automatic graph number switching, B-3, C-4

Demonstration program,

BASIC-PLUS, 3-2
Destination point, 1-3
Devices,

storage, A-3

Disabling graphic figures, 1-2, 2-3, 3-4
Display,

suppressing text, 2-18, 3-12
Display-only device,
VTS55asa, 2-2, 3-3
Displaying text, 2-14, 3-13
Displays,

BASIC-PLUS definitions, 3-1
BASIC-PLUS demonstration program, 3-2

vertical text, 3-13, B-4
Drawing vectors, 2-11, 3-10

BASIC-PLUS programming rules, 3-2
Blank screen, 1-3
Bootstrap, A-1

Channel,
communication, 1-4

Character,
ASCII, 1-1
Characters,
display of, 2-14, 3-13

Enabling graphic figures, 1-2, 2-3, 3-4
Erasing graphs, 1-2

Erasing graphs with vectors, 1-4
Erasing text, 2-13, 2-16, 3-11, 3-12
Error return, 3-3
Escape mode, 1-1, 2-16

Escape sequence, 1-1, 2-16, 3-11
Event flags, 1-4, 2-2

erasing, 2-13, 2-16, 3-11

CLEAR, 2-13
Clearing graphic memory, 1-2, 2-4, 3-4
Code,

condition, 3-1
Commas in PLOTSS, 2-2
trailing, 2-4
Common status table, B-1

Communication channel, 1-4

Figures,
graphic, 1-2
Figures with same graph number, 3-15

Flags,

event, 1-4, 2-2
FNVS format, 3-3

Format,

FNVS, 3-3

Condition code, 3-1

Coordinates,
defining starting, 2-11, 3-9
starting, 1-3

COPY key, 2-18, 3-13
Copying, 2-18, 3-12

general PLOTSS, 2-1

FORTRAN histograms, B-3

General PLOTSS format, 2-1
Graph number, 1-2

figures with same, 3-15

automatic, 2-18, 3-12

Cursor, 1-2
Position, 2-13, 2-16, 3-11

selecting, 2-3, 3-4

Graph number switching, automatic, B-3, C-4
Graphic figures, 1-2
disabling, 1-2, 2-3, 3-4

DECpack, A-1, C-1
DECtape, A-2, C-1

Defining starting coordinates, 2-11, 3-9
Definitions,
BASIC-PLUS, 3-1

enabling, 1-2, 2-3, 3-4

Graphic memory, 1-2
clearing, 2-4, 3-4

Graphic mode, 1-1, 1-2
Graphing program, sample, 2-6, 3-6

Index-1

Index

Graphs, 1-2, 2-3, 3-1

Overlaid program, 2-2

erasing, 1-2
plotting, 1-2

Pause, READ for programmed, 2-7

plotting BASIC-PLUS, 3-5

PAUSE statement, 2-7, 2-16, 2-18
PLOTSS,

plotting

FORTR AN, 2-5

shaded, 1-2

commas in, 2-2

shading regular, B-3, C-4

PLOTSS format, general, 2-1

starting position for, 2-11, 3-9

Plotting graphs, 1-2

Graphs from arrays, plotting, 1-3

BASIC-PLUS, 3-5

Graphs with vectors, erasing, 1-4

FORTRAN, 2-5

Plotting graphs from arrays, 1-3
Hard copy unit, 1-1, 2-17, 2-18, 3-12

Plotting horizontal lines, 2-7, 3-7

Histograms, 3-1

Plotting markers, 2-9, 3-8

FORTRAN, B-3

Plotting single points, 1-3

Hold screen command, 2-17, 3-12

Plotting vertical lines, 2-8, 3-8

Home position, 1-2

Point,

Horizontal lines, 1-2, 2-7, 3-7

destination, 1-3
single, 1-3, 2-11, 3-5, 3-9

IAS, 2-2, 2-16, A-2

Position,

Initialization, 3-1

cursor, 2-13, 2-16, 3-11

ITBL, 2-1, B-1

home, 1-2

Position for graphs, starting, 2-11, 3-9
Line segments, 1-3

Program,

Line-drawing program, sample, 2-8, 3-8

overlaid, 2-2

Lines,

sample for markers, 2-10, 3-9

horizontal, 1-2

sample for vectors, 2-12, 3-10

plotting horizontal, 2-7, 3-7

sample graphing, 2-6, 3-6

plotting vertical, 2-8, 3-8

sample line-drawing, 2-8, 3-8

vertical, 1-2,

sample text-display, 2-14, 3-14

Listings, 2-18, 3-12

Programmed pause, READ for, 2-7

Logical unit number, 1-4, 2-2, 3-3

Programming rules, BASIC-PLUS, 3-2

Logical unit numbers, assigning, 2-2

READ for programmed pause, 2-7
Magnetic tape, A-2, C-1

Registers, 1-2, 2-3

Markers, 1-2

Regular graphs, shading, B-3, C-4

plotting, 2-9, 3-8

sample program for, 2-10, 3-9
Memory,

graphic, 1-2
Messages,

unwanted, 2-3, 3-3
MID function, 3-13

Release screen command, 2-17, 3-12
RESUME, 2-16, 2-18
Return, error, 3-3
RKO0S, A-1, C-1
RSTS/E, 1-4

RSX-11, 1-4, 2-2, 2-16, 2-18, A-2
Rules,

BASIC-PLUS programming, 3-2

Mode,

alphanumeric, 1-1, 1-3
escape, 1-1, 2-16
graphic, 1-1, 1-2
terminal, 1-1
Name,

task, 2-16
NUL character, 2-14
Number,

graph, 2-3, 3-4

logical unit, 1-4, 2-2, 3-3
terminal, 1-4, 2-2, 3-3

Same graph number, figures with, 3-15
Sample graphing program, 2-6, 3-6
Sample line-drawing program, 2-8, 3-8
Sample program for markers, 2-10, 3-9
Sample program for vectors, 2-12, 3-10
Sample text-display program, 2-14, 3-14
Scale, vertical, B-2, C-3
Screen, blank 1-3
SCROLL key, 2-18, 3-12
Scrolling, 2-17
Selecting graph number, 1-2, 2-3, 3-4
Index-2

Index

Shaded graphs, 1-2

Text displays, vertical, 3-13, B-4
Text-display program, sample, 2-14, 3-14

Shading regular graphs, B-3, C-4

Trailing commas, 2-4

Sequence, escape, 1-1, 2-16, 3-11

Single points, 1-3, 2-5, 2-11, 3-5, 3-9
Unwanted messages, 2-3, 3-3
Use of status table, B-1

Starting coordinates, 1-3

defining, 2-11, 3-9
Starting position for graphs, 2-11, 3-9

Vs, 3-5

Status table, 2-1

common, B-1

Vector,

zeroing, 1-4, B-4, C-4

use of, B-1
Storage devices, A-3

Vectors, 1-3

Suppressing text display, 2-18, 3-12

drawing, 2-11, 3-10

Switching terminal modes, 1-3

erasing graphs with, 1-4, B-4, C-4
sample program for, 2-12, 3-10

Table, status, 2-1, B-1

Vertical lines, 1-2, 2-5, 2-8, 3-1, 3-8

Task-name, 2-16

Vertical scale, B-2, C-3

Terminal mode, 1-1

Vertical text displays, 3-13, B-4

switching, 1-3
Terminal number, 1-4, 2-2, 3-3

VTS5 as a display-only device, 2-2, 3-3
VTS55.BAS, 3-1

Text,

displaying, 2-14, 3-13

X position, starting, 2-7, 3-9

erasing, 2-16, 2-17, 3-11
Text display, suppressing, 2-18, 3-12

Zeroing vector, 1-4, B-4, C-4

Index-3

VT55 Programming Manual

AA-4949A-TC
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