Object Code Accelerator Manual

Debugging OCA Programs

Object Code Accelerator Manual—528144-003

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maintained, no change is required to run existing TNS programs on TNS/E systems

and, with very few exceptions, debugging is the same.

both memory and the TNS register stack are the same as if the program were

executing on a TNS system. No optimizations cross register-exact points. Complex

statements might contain several such points: at each function call, privileged

instruction, and embedded assignment. Register-exact points are a subset of memory-

exact points.

By default, OCA defines register-exact points only where necessary for correct

execution; for example, following procedure calls. Many statements have no register-

exact point. Register-exact points are the only points at which an accelerated program

makes transitions to and from executing TNS instructions. Some complex statements

might contain several register-exact points, particularly at each function call.

At register-exact points, you can safely use all Visual Inspect, Native Inspect, or

Inspect debugging commands (including modifying memory variables) as if the

program were on a TNS system.

Memory-Exact Points

Memory-exact points are locations in an accelerated program at which the values in

memory (but not necessarily in the register stack) are the same as if the TNS/E

program were running on a TNS processor. Displaying memory variables gives

accurate results at memory-exact points. However, modifying memory variables at

these points might not reliably affect the program’s subsequent actions because the

changed variable might have already been loaded in registers. Most source statement

boundaries are memory-exact points. Register-exact points are a subset of memory-

exact points.

Nonexact Points

Nonexact points are locations in an accelerated program that are not memory-exact

points. Most code locations in an accelerated program are nonexact points. At

nonexact points, the TNS program state is not consistent, displayed memory might not

be current, and the reported current program counter location is only approximate.

Attempting to modify memory at a nonexact point might result in the data being

overwritten by a subsequent store operation.

A Strategy for Debugging

In general, debug the TNS object code version of your complete program before

running OCA. Then accelerate a version of the program containing an Inspect symbols

region, using the Visual Inspect or Native Inspect, and perform final testing.