INT 15 U - OS HOOK - ROM BIOS TRACING CALLOUT (PS30/286,PS50Z,PS95)
        AH = C5h
        AL = interrupt being invoked
            01h INT 19
            02h INT 14
            03h INT 16
            04h INT 40 (floppy INT 13)
            05h INT 17
            06h INT 10
            07h INT 12
            08h INT 11
            09h INT 1A
Return: all registers except AX must be preserved
Notes:  called as the very first action of the indicated ROM BIOS interrupt
          handlers on the PS/2 Models 30/286, 50Z, and 95
        default handler does nothing and returns CF clear for the above
          subfunctions, CF set and AH=86h for all other subfunctions
        value of AX passed to the original interrupt handler is pushed on
          stack immediately prior to call