Radio Shack Telephone Interface II Manual

e
8. GOSUB
statement,
RETURN
statement
When
you use
a
certain processing procedure a number of times,
you will
have
a more
efficient
program
if
you
handle
these procedures
as
a sub-routine.
When
a program comes
to
a GOSUB statement, the Computer moves
to
a
specified
line
or
label
and
executes the
programs stored
there.
At
the end
of
a
sub-routine
you
must
add a RETURN statement,
which
returns program
execu-
tion
to the
statement immediately
after the GOSUB statement.
A subroutine can
contain other
subroutines, up to a maximum of 4
levels.
(1)
GOSUB statement
General
form
{1)
GOSUB
<
Expression
>
Example:
GOSUB 10
GOSUB A
General
form
(2)
GOSUB
"Character"
[Character
variable]
Example:
GOSUB
"ABC"
GOSUB A$
<
The
RETURN statement
must
be at
the end
of
a
line
(it can
not be followed
by
any
other
another
statement
on
the
same
line.
(2)
RETURN
statement
General
form
RETURN
The
RETURN
statement must be at
the end
of
a
line
(it
can not
be
followed
by
any
other
statement
on
that line).
Note: An
error (error
code:
3)
occurs,
if
a
RETURN
is used
without
a
GOSUB earlier
on.
Also
be
sure
to
put
END statement
on
end of
main
routine,
else
computer
will
go
into
subroutine
and error
3
will
occur.
Example
1
Main
routine
80;
GOSUB400'
220:GOSUB300'
Subroutine
(1st
stage)
.400:
450:
GOSUB
:
510'
500:
RETURN
300:
"340
: RETURN
Subroutine
(2nd
stage)
510:
560:
GOSUB600
Subroutine
(3rd
stage)
600:
590:
RETURN
URN
62

Radio Shack Telephone Interface II Specifications

General

Brand	Radio Shack
Model	Telephone Interface II
Category	Desktop
Language	English