Vector Basic Interpreter Basic 80 Reference Manual - page 107
of
190
WAIT
where I and
J
are integer expressions
SK, Extended, Disk
To suspend program
execution
while
monitoring
the status of a machine input port.
The
WAIT
statement
causes
execution
to
be
suspended
until
a specified machine input port
develops a specified bit pattern.
The data read
at
the port is exclusive ORIed with the integer
expression J, and then AND Ied with
I.
If
the
result
is
zero,
BASIC-SO loops back and reads
the data at the port again.
If
the
result
is
nonzero,
execution
continues
with
the
next
statement.
If
J
is omitted, it is assumed to be
zero.
It is possible to enter an
infinite
loop
with
the
WAIT
statement,
in
which case it will be
necessary to manually restart the machine.