Hi,

I know it's possible, but I can't remember the exact FPC parameters. How do I see the assembler generated by FPC for my source code?

I need to do some optimisation comparisons looking at the assembler generated.

eg:
Is assembler code generated for a call to a blank (no content) procedure? The content of the procedure might be IFDEF'd out.

Regards,
- Graeme -

_______________________________________________
fpGUI - a cross-platform Free Pascal GUI toolkit
http://opensoft.homeip.net/fpgui/

Graeme Geldenhuys wrote

Hi, I know it's possible, but I can't remember the exact FPC parameters. How do I see the assembler generated by FPC for my source code?

Read ppc386 -h.

Micha

Micha Nelissen wrote

Read ppc386 -h.

OK, I meant to say, I already looked at the parameter help, I'm just not sure which one I need to use. I would guess -al is what I am looking for? Is there more information on what all these options do? Sorry, my assembler is rusty!

-a The compiler doesn't delete the generated assembler file -al List sourcecode lines in assembler file -an List node info in assembler file
-ap Use pipes instead of creating temporary assembler files -ar List register allocation/release info in assembler file -at List temp allocation/release info in assembler file

PS:
Sorry, I only realized now, that I posted this thread in the fpc-devel mailing list. I meant for it to go to fpc-pascal.

Regards,
- Graeme -

_______________________________________________
fpGUI - a cross-platform Free Pascal GUI toolkit
http://opensoft.homeip.net/fpgui/

-al : This is the one you need.

Michael.

You could use breakpoints and the (dis-)assembler window of MSEide, it lists mixed pascal and machine code.
The SVN trunk version has some improvements in (dis-)assembler window, for example the possibility to set breakpoints on machine instructions.

Martin

Martin Schreiber wrote

You could use breakpoints and the (dis-)assembler window of MSEide, it lists mixed pascal and machine code.

Thanks Martin, I'll take a look.

What I'm trying to find out (with my rusty assembler knowledge) is if a lot of IFDEF's around procedure calls, compared to only one IFDEF inside a procedure would make a difference in performance and the code generated.

I would prefer example 2 (it looks cleaner and would be less work), and from my quick/crude analysis, it seems both options generate pretty much the same code if the gDEBUG define is disabled (does NOT exist).

Example #1...

  procedure Log(AParam1: string);
  begin
    writeln('LOG: ' + AParam1);
  end;
var
  i, j: integer;
  s: string;
begin
  {$IFDEF gDEBUG} Log('Starting...'); {$ENDIF}
  s := '%d + %d = %d';
  i := 5;
  j := 2;
  {$IFDEF gDEBUG} Log('calculating result'); {$ENDIF}
  {$IFDEF gDEBUG} Log(Format(s, [i, j, i+j])); {$ENDIF}
  {$IFDEF gDEBUG} Log('Done.'); {$ENDIF}
end.

versus Example #2...

  procedure Log(AParam1: string);
  begin
    {$IFDEF gDEBUG}
    writeln('LOG: ' + AParam1);
    {$ENDIF}
  end;
var
  i, j: integer;
  s: string;
begin
  Log('Starting...');
  s := '%d + %d = %d';
  i := 5;
  j := 2;
  Log('calculating result');
  Log(Format(s, [i, j, i+j]));
  Log('Done.');
end.

Regards,
- Graeme -

_______________________________________________
fpGUI - a cross-platform Free Pascal GUI toolkit
http://opensoft.homeip.net/fpgui/

For the people who don't know MSEide attached a screenshot, I hope the file is not too big. It is with -O3. With inline there is still some overhead because of the string variable.

Martin

Hi

Try fpc -sh

regards

Nataraj

Martin Schreiber wrote

For the people who don't know MSEide attached a screenshot, I hope the file is not too big. It is with -O3. With inline there is still some overhead because of the string variable.

OK, thanks Martin. Debugging in MSEide seems quite impressive. I can see you put a lot of effort into writing it.

PS:
The image was received fine. I noticed with my own experimentation that small screenshots (not photos) work better as GIF images. It's a much better option for size reduction with no visual loss. Your image as PNG is 28K. As a GIF it's only 17.5K
:-) Don't use JPG's, they are useless and look damn ugly!

Regards,
- Graeme -

_______________________________________________
fpGUI - a cross-platform Free Pascal GUI toolkit
http://opensoft.homeip.net/fpgui/

Because I implement so many bugs, I need an excellent IDE. ;-)

Martin

Graeme Geldenhuys wrote

Is assembler code generated for a call to a blank (no content) procedure? The content of the procedure might be IFDEF'd out.

I've checked it, and it does. Mark the procedure as inline together with IFDEF-ing its code, and there will be no overhead.

David

It's 9K in PNG if you use a palette/256 colors, much like GIF does ;)

David

David Pethes wrote

> as PNG is 28K. As a GIF it's only 17.5K > :-) Don't use JPG's, they are useless and look damn ugly! It's 9K in PNG if you use a palette/256 colors, much like GIF does ;)

Cool! I never thought to look at the colour palette information.

Regards,
- Graeme -

_______________________________________________
fpGUI - a cross-platform Free Pascal GUI toolkit
http://opensoft.homeip.net/fpgui/

It's 9K in PNG if you use a palette/256 colors, much like GIF does ;)

Firefox shows PNGs (and JPGs) within the message, while you would need to open an external viewer for GIFs. So PNG is really nice here !

-Michael

Michael Schnell wrote

Firefox shows PNGs (and JPGs) within the message, while you would need to open an external viewer for GIFs. So PNG is really nice here !

Huh?? Many sites use gif images!
Firefox supports PNG, GIF, JPG etc.. all natively. At least my version does (Firefox v3). I just tested this as well. I could view a website and my gmail with uses both gif and png files in the content.

Ah, I see your problem:
User-Agent: Thunderbird 2.0.0.16 (Windows/20080708)

Please upgrade to a working OS - something like Linux. ;-) Actually my wife's computer uses Firefox 2 under Windows, and she as no issues with viewing gif images either.

Regards,
- Graeme -

_______________________________________________
fpGUI - a cross-platform Free Pascal GUI toolkit
http://opensoft.homeip.net/fpgui/

Sorry Typo: Thunderbird !

-Michael

Michael Schnell wrote

Huh?? Sorry Typo: Thunderbird !

Makes no difference, that test email I mentioned was from one account to my work account. HTML email (which I hate) or plain text emails... Thunderbird shows png, gif and jpg inline, without issues. In the case of plain text, the images are inline at the end of the email - one image after another.

Anyway, we are way off-topic here...

Regards,
- Graeme -

_______________________________________________
fpGUI - a cross-platform Free Pascal GUI toolkit
http://opensoft.homeip.net/fpgui/

You are right. it does show gif. No idea why it did not when I tested this some time ago...
-Michael

As I was porting things from delphi to fp today I noticed the following difference:

Delphi (2,5) : GetMem(p, 0) will set p to nil. FPC (2.2.2, 2.3.1) : GetMem(p, 0) will assign something to p

Clearly, the above calls are bad karma (which I have been practicing, apparently). Delphi's help does not say what GetMem should do when the size is 0 (realloc does). On the other hand, assigning something is a bad idea too, as it suggests at least Size(pointer) amount of storage, unless that memory spot is somehow marked as "empty", etc.

Do you think this should be reported as a feature, or should the definition of GetMem be changed to cover this case. Note that it is desirable to specify explictly what GetMem(p, 0) should do, since one can in principle provide a separate heap manager. Therefore, behavior of use-supplied getmem should be unniform.

Peter Popov

Peter Popov wrote

size is 0 (realloc does). On the other hand, assigning something is a bad idea too, as it suggests at least Size(pointer) amount of storage, unless that memory spot is somehow marked as "empty", etc.

How does it suggest a storage space with size > 0 ?

Micha

Well, if it points to something, then there is space, isn't it? Unless it is clearly mentioned in the documentation that GetMem(p,0) results in p being undefined and it is put as a requirement for any custom implementation of a heap manager.
Either way would work.

Peter

Should it be forbidden do allocate a buffer of size 0 and reallocate it later for a bigger size ?

-Michael

Peter Popov wrote

Well, if it points to something, then there is space, isn't it? Unless it is clearly mentioned in the documentation that GetMem(p,0) results in

You get a pointer to some place where you may store 0 bytes, so nothing :-).

This can be useful because otherwise you may think the allocation failed if you get nil back. (And you've disabled heap exception).

Micha

In FPC it is done by design. If 0 bytes are asked we allocate at least the minimum alignment to get a valid pointer. This is done for compatibility with TP7.0 that returns the value of heapptr which is also a valid pointer.

Peter

you have a point

Thanks for the clarification!
I guess if you switch to reallocmem entirely, there will be delphi compatibility, yes?

Peter

reallocmem indeed frees the memory and sets the pointer to nil if you specify "0" as the memory size.

Jonas

Look at thread "AllocMem(0)nil" at 25.03.08. I had the same problem.

Petr

AllocMem uses internally the same memory allocation as GetMem. So the behaviour of FPC is by design.

Peter