[sdcc-devel]How to improve overlaying in the SDCC? (DSEG overflow problems)

[Wojciech Z. <wz...@is...>]

Hi all SDCC Users & Developers,

I don't know if I'm the only one who may not successfully compile the
project with SDCC because of its DSEG overlaying limitations?
The problem is that SDCC does not overlay the local variables (and
internally used variables) in functions which call another functions.
This results in DSEG overflows, when writing programs requiring more than
one level of function calls. Unfortunately some really simple operations 
(like 16 bit * 16 bit multiplications) are implemented as function calls
(not as macros), so it is very easy to run into that problem (it is really
difficult to move all the 16bit and float operations into the main ;-) ).

  I would like to know if I'm really the only one interested in improving
  that?

  Is it possible to implement the "multilevel" overlaying in SDCC?

  I've experimented with asx8051 and aslink, and it seems to me that it 
  is possible to define the multiple overlay areas, necessary to implement
  such a feature...

  My current knowledge of SDCC internals is not sufficient to recognize 
  how difficult would it be to add the "call tree" analysis to the SDCC.
  Could someone please help me to find the answer?
  All I've found in the current sources is the 
  static bool canOverlayLocals (eBBlock **ebbs, int count) function
  which just checks if the function calls another functions...
  Certainly this approach should be changed and replaced by assignment
  an "overlay level" to each function, depending on what functions does it
  call, and where is it called from...

  Maybe it is imposible at all without really serious changes in the whole
  SDCC?

-- 

					TIA & Greetings
					Wojciech Zabolotny
					wz...@is...