Type III C lass A Program

TRAP Function
Purpose:
The TRAP function sets a user·s return
interrupt. This return overrides the call
external interrupt.
Calling Sequence:
PLIST DS
DC
DC
on
CLSeTRAp·
ACtrapsubr)
for an externa1
to DEBUG on an
where trapsuhr is the location transferred to on an external
interrupt. If the parameter trapsubr is a zero, the return
is reset to go to DEBUG on an external interrupt.
Usage:
The user·s interrupt routine should set a flag which should
be examined by the main line program. After the flag is
setl• this routine should return to the location specified in
GPR14 on entry. All other general registers can be used as
desired. The main line program should periodically examine
the trap flag to determine whether an external interrupt has
occurred.
Error Returns:
None.
TRAP Function 315