[fpc-devel] StackBottom

[Vincent Snijders]

Hi,

If I run the following program on windows xp, it shows me that the 
StackBottom is located at $2FE80. I thought that the stack was always 
contained in complete pages and therefore the StackBottom should be at a 
  4k boundary. Is that correct?

Assuming this, the correct value for the StackBottom should be $30000.
Then StackBottom should be initialized as

StackBottom := (Sptr - StackLength + $FFF) AND $FFFFF000;

(at program start Sptr doesn't point to the exact top of the stack).

I stumbled on this issue, because for backtrace some values at the top 
of the stack were not considered valid frame pointers.

Vincent

==================

program Project1;

{$mode objfpc}{$H+}

uses
   Classes
   { add your units here };

begin
   writeln(HexStr(PtrUInt(StackBottom),SizeOf(Pointer)*2));
   readln;
end.