Re: Finding library call information (GNAT-Linux)

["David C. Hoos" <david.c.hoos.sr@ada95.com>]

It is really difficult to answer questions like this which do not
identify the hardware platform, OS version, and compiler
version, but since we're talking about _some_ version of gnat,
we can determine the following:

The names with double underscores represent the link names of
Ada subprograms as indicated by the many examples in the
Gnat User Guide.  The gnat source code for the subprograms
in question documents in code and in comments what the
subprograms do.

For the name with only single underscores, a grep of the files
in the adainclude directory reveals that it is the link name of
a gnat subprogram exported so it can be called from C code.
Here, again, what the subprogram does is documented in the
source code.

Hope this helps

----- Original Message ----- 
From: "Carl Franklin" <CarlR-junk@houston.rr.com>
Newsgroups: comp.lang.ada
To: <comp.lang.ada@ada-france.org>
Sent: Monday, August 30, 2004 3:21 PM
Subject: Finding library call information (GNAT-Linux)


> We are chasing some problems... that are rather interesting...
>
> The environment - is a Simulation...
>
>   containing a Robot arm, etc...
>
>   We are on a multi-processor system (2 Pentium IIIs)
>
>   Now, when a particular version of the arm was delivered - constraint
> errors - typically having to do with double precision floating point
> started occuring... (very intermittently)... and when they occur... they
> occur in *flurries*...
>
>   The personnel *instrumented* the code - and the results are very
squirelly...
>
>   Constaint Errors being returned for zero (a valid value) - other
> times... constraint errors on a number (0 <- zero and by this I mean
> 0.0)... multiplied by another number - returning some really interesting
> values...
>
>   The suspicion is that a driver might be stomping on a register -
> however, that doesn't seem all that reasonable...
>
>   Then, we created a little Double Precision test - and ran this as a
> seperate process - runs for forever... or seemingly so... with no
> problems...
>
>   Then, we ran this little DP process while the Real-Time simulation was
> active... and low & behold... intermittent errors (constraint problems)...
>
>   Trying to delve deeper - I was given the assembly source for the program
> - and am trying to instrument at a *somewhat lower* level (smile)... than
> we can do from ADA code...
>
>   Getting the assembly listing - there are several *calls*... that appear
> to be ada/system libraries.  The *system* is not Linux system - as the
> text strings are not found going through Linux source repository *free
> text* searches (or identifier searches)...  So, perhaps they are *Ada
> System* interfaces...
>
>   I am wondering where to find information about the calls and the results
> I should expect... (what the heck they are doing)...
>
> specifically the following calls are of interests...
>      system__arith_64__multiply_with_ovflo_check
>      _gnat_stack_check
>      system__secondary_stack__ss_allocate
>
> and several others...
>
>   I'm wondering - where I can find the *source* or documentation on this
> *called* routines...  So, I'll be able to completely understand the flow
> within the assembly code...
>
> Thank You for Any assistance!,
> Carl R. Franklin
>
> -- 
>                                         Just me,
>                                         Carl R. Franklin
> ***********---------------************-----------------************
> There is never a need to outrun anything you can outwit - Garfield (the
cat)
> ***********---------------************-----------------************
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