INT 2F U - Microsoft Profiler (PROF.COM/VPROD.386) - SET SAMPLING RATE
        AX = 4502h
        BL = sampling rate for PROF.COM (0 < BL <= 13)
            (01h = 8192/s, 04h = 1024/s, 08h = 32/s, 0Dh = 1/s)
        CX = sampling rate for VPROD.386
Note:   for PROF.COM, this programs the CMOS clock by setting BL+2 as the
          low four bits of CMOS register 0Ah.  The interruption rate is
          1 SHL (15 - BL) per second.
SeeAlso: AX=4503h