## Graphics Adapter Device Driver Reference

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### WAIT Command

The WAIT command should be used to wait on vertical retrace or to wait on a desired status. The command allows for a time-out in milliseconds. The condition for wait has been met if port value ANDed with andmask has the waitonvalue. Register r0 is set to convey the status:

TRUE (1) means that the waiting condition has been met.
FALSE means that a time-out has occurred.

The wait is interruptable. This command should not be used in Cleanup sections.

The port can be an immediate value, which presumes that the port is an I/O port or a declared port. In these cases, the port's declaration type is used in interpreting this command.

    WAIT( port, andmask, timeout, waitonvalue );
    <andmask>  ::= <number>
    <timeout>  ::= <number>
    <waitonvalue> ::= <number>

    <port>  ::= <  constant>  |  <pio variable>  |  <mmio variable>