BASCOM 1.11.9.1 ROMIMAGE 20 Bytes bigger

knickohr · Joined: 24 Jan 2007 Posts: 97 Location: Germany

Hello,

just downloaded the new BASCOM-Version and compiled my old programs. The ROMIMAGE is now 20 Bytes bigger, why ?

"Optimize Code" is on.

It's only 20 Bytes, but a few programs will now not fit in the Chip Sad

Thomas

AdrianJ · Joined: 16 Jan 2006 Posts: 2477 Location: Queensland

If the compiler is changed to improve code generation / take out bugs / add extra features for newer chips, then you can expect compiled code to be different, sometimes radically. If the code works with the old compile, then just continue to use it. Just gives you headaches for code maintenance. One option many people use is to keep a complete install of the older compiler, plus all source code and generated object code as a separate disk folder or on CDrom. Them you can always revert.

TSEYFARTH · Joined: 01 Jul 2006 Posts: 1053

I have the same problem! In one area, it is a tad over 99% with 1.11.9 with the newer it is over 101%.

Really makes life challenging.... Especially after working to reduce the size already to fit.

Is there any way to adjust this???

Tim

Luciano · Joined: 29 Nov 2004 Posts: 3149 Location: Italy

TSEYFARTH · Joined: 01 Jul 2006 Posts: 1053

I'd love to do that Smile

I've asked, received and tried a bunch of tricks to reduce the size - which it did (thanks to suggestions from the forum).

The project is done at this point - would be nice for future maintenance (and of course possible bug fixes) to be able to use the most current IDE...

Is there any way to fix this via a setting in the IDE???

Tim

knickohr · Joined: 24 Jan 2007 Posts: 97 Location: Germany

Hi Tim,

try to optimize your code !

For example :
if a=1 and b=2 then
...
end if

Optimized :
if a=1 then
if b=2 then
....
end if
end if

Will get 6 Bytes

Example 2 :
if c=3 then
d=0
end if

Optimized :
if c=3 then d=0

Will get another 2 Bytes

Example 3 :
If you use the Date="..." or Time="..." command, try to set the date or time in another way like _day=5 or so. The date and time commands are byte-wasting.

Thomas

TSEYFARTH · Joined: 01 Jul 2006 Posts: 1053

I've used other techniques to optimize, but dont think I have used your ideas (I have to check it has been a while...

However, why wouldnt the compiler compile the same in either case of?
Example 2 :
if c=3 then
d=0
end if

Optimized :
if c=3 then d=0

I dont understand why it wouldn't even with select case statemets too act the same. I have seen where it take more clock cycles to execute which again, to me, does not make sense but I am also not anywhere close to the level of a programmer who makes compilers!

Tim

DToolan · Posted: Wed Feb 27, 2008 10:45 pm Post subject:

knickohr · Joined: 24 Jan 2007 Posts: 97 Location: Germany

Tim, I don't know the answer too. The answer kows the programmer of the compiler.

Another Example :

a=chr(32) will waste also bytes, try to type a=" ". If it is possible, search the correct character in your code-table, copy and paste it in your code.

What other code-optimizing-tricks do you use ?

Thomas

TSEYFARTH · Joined: 01 Jul 2006 Posts: 1053

DToolan you are talking like a real Homer!

This is a mega48 not 1281. There are no strings whatsoever in the program.

Sure wish you'd chime in helpfully without the undeserved shots.
tim

DToolan · Posted: Wed Feb 27, 2008 10:59 pm Post subject:

TSEYFARTH · Joined: 01 Jul 2006 Posts: 1053

Thomas

your nesting of the AND's worked (at least to reduce size I have not tested yet). I had 4 places where at least 1 AND was used and by nesting them, it reduced the compiled size by 2% to 97% on the 1.11.9.0 version.

I'll look for a few others too...

But, it would be nice if the variances were not there due to compilation.

Anyway back to work and thank you all!
Tim

TSEYFARTH · Joined: 01 Jul 2006 Posts: 1053

Thomas

TSEYFARTH · Joined: 01 Jul 2006 Posts: 1053

One more item that makes the code smaller, but less readable (in my opinion) is getting rid of any un-necessary Subs. For example, I like to use a start up sub. This is really not necessary since it could go before the main loop. In the case of my 1281 where I am using only 11% of the program space, it can stay. But in the case of the MEGA48, it was not used.

Tim

AdrianJ · Joined: 16 Jan 2006 Posts: 2477 Location: Queensland

Any program where you use a Sub/Function only once should be reduced to in-line code. And you can gain more space even for multiple calls if you can use a Gosub rather than a Sub. Yes you have to use global variables, which can be a nuisance, but you still save space, particularly if you pass many parameters in the call.