Int 15h, 86h            Wait                                       XT-286, AT

    Waits a specified number of microseconds before returning control
    to the caller.

        Entry   AH    = 86h
                CX:DX = Number of microseconds to elapse

        Return  CF Set if error or wait in progress, else cleared

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    This service is not available for the PC, PCjr, and the XT.

    The real-time clock is used to count the number of microseconds.
    The granularity of the time is 976 microseconds. CX is the
    high-order word of the count. For example, if CX is 98h and DX is
    9680h, a 10-second delay would be specified.