INT 15,86 - Elapsed Time Wait (AT and PS/2)

AH = 86h

CX,DX = number of microseconds to wait (976 µs resolution)

on return:

CF = set if error (PC,PCjr,XT)

= set if wait in progress

= clear if successful wait

AH = 80h for PC and PCjr

= 86h for XT

- AT and PS/2 only for system timing

- not designed for user application usage