INT 15 - BIOS - SET EVENT WAIT INTERVAL (AT,PS50+)
AH = 83h
AL = subfunction
00h set interval
CX:DX = microseconds to delay
ES:BX -> byte whose high bit is to be set at end of interval
01h cancel wait interval
Return: CF set on error or function already busy
AH = status
80h invalid command (PC,PCjr)
86h function not supported (XT and later)
CF clear if successful
Note:   the resolution of the wait period is 977 microseconds on most systems
because most BIOSes use the 1/1024 second fast interrupt from the AT
real-time clock chip which is available on INT 70
SeeAlso: INT 70

See also: 1586

1583 - BIOS - SET EVENT WAIT INTERVAL (AT,PS50+)