Slide 25

TDF server is both Amode and Rmode 64-able. The code uses a 64 bit shared memory object to manage almost all of its control structures minimizing its impact on the debugged address space. The z Architecture TRAP instruction requires some 31 bit storage which is kept in the applications address space. About half of the TDF server can run above the bar substantially reducing CSA usage by TDF. The other half, particularly code involved in SVC and PC screening and RTM exit processing must reside below the bar until the architecture allows this code to be moved above the bar.

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