Your program's defined limits

IDF considers "your program" to be any location within the initial target program module, and any more program modules that you have defined.

When the target is loaded, IDF determines its limits by examining the module file.
Extra modules are implicitly defined as the result of the triggering of a deferred breakpoint that was established with a DBREAK command.
Extra modules are explicitly defined with the IDF MODULE command:
- If the module is a nucleus extension, establish the module definition with a MODULE NUCEXT command.
- If the module is a transient program, establish the module definition with a MODULE TRANS command.
- Define an explicit module origin and size with MODULE BASE and MODULE SIZE commands.
- You can establish an explicit module's CSECT structure with a LOAD SYMBOLS command (see LOAD).

The origin and size of the programs known to IDF are displayed in the Target Status window, when open.

Whenever possible, IDF tells you if your program is about to branch to a location outside its defined limits. This is often useful in finding a "wild branch", for example to location zero.

If you have specified the TRACEALL option, IDF considers the defined limits of your program to begin at location zero and extend upward to the address specified in the VMSIZE word of NUCON. Thus when you specify TRACEALL, you can trace through all of virtual memory.

Take care if you attempt to trace through protected (read only) storage.

If you specify the RISK option, IDF considers all of memory to be within your program's defined limits. Thus you could attempt to step through code in a DCSS that is actually above the address specified in the VMSIZE word of NUCON.