When a runtime error happens, I would like to display all possible information
The compiler we are using today can give a message like this
Runtime error 27
Index out of range
The value -4 is not in the range o 0 .. 3000.
Near line 103
Procedure Test

Would it be possible to do something like this if I write a new exit procedure?

If this is not possible how about the Turbo Pascal way using the map file to track the Procedure Name and the source code line number. I do not think this is possible with FPC because of the separate assembler and linker, but maybe there is a way around this.
I am running the FPC code on an embedded ARM platform without any operating system.

Put into your fpc.cfg file:

-gl

to generate the line numbers (that's the really relevant one, right?) It will also say what procedure it's inside, as well as a backtrace of calling procedures, and their line numbers.

You can also find in fpc.cfg a number of other flags to generate debugging info.

I don't know if it's possible to generate a line like "the number -4 is not between 0 and 3000" ... although that would be kind of nice, come to think of it.

~David.