Laser 128 - Wait

BASIC COMMANDS AND STATEMENTS
3.66 WAIT
Purpose: To suspend a program's
execution while watching the
stat us of an input port.
Format: WAIT portnumber, n [.m]
Comments: The command suspends a
program's execution until a
specified input port develops an
expected bit pattern.
The command loops around,
reads the data at the port, XORs
it with the integer va lue m, and
then ANDs the result with th e
integer va lue n. If m is not
specified, it is taken to be zero .
If the result at the end of the
loop is zero, the loop starts over
again.
If the result is not zero, then the
program resumes execution at
the next executable statement
after WAIT.
Careful: You can get into a
contin uous loop with the use of
the WAIT command. Warm start
the computer by pressing CTRL
+ RESET if you believe this has
happened. It will let you out of
the loop, and return you to
command level.
II-101