Comment that there are basically two stacks, on ia64.
Accept two stacks w/o ifdef.
Check direction for both stacks (do not assume direction of ia64 second stack).
Remove excess asserts (esp. ignore null, but also that contains context).
Process second stack even if first stack absent, unlikely but simple.
Comment that there are basically two stacks, on ia64. Accept two stacks w/o ifdef. Check direction for both stacks (do not assume direction of ia64 second stack). Remove excess asserts (esp. ignore null, but also that contains context). Process second stack even if first stack absent, unlikely but simple.