Function too Large - Main (?)

Arizona Chris · Joined: 20 Dec 2014 Posts: 69 Location: Arizona

HI all,

I run into this error message from time to time, and usually when I have a deadline to meet at work! Ive seen this come up with the ROM only at 35% sometimes, making it a real enigma. it prevents the program from compiling.

So here are my questions on this issue, Id like your thoughts on any of them if possible:

-- IS there a maximum size for Main or any other function if you are not limited by program space (ROM) ?

-- Is there a way around this If I encounter it while programming?

-- Can this be CHANGED to a higher limit?

-- is there a way to monitor the size of main so I can see this limit coming?

Right now I usually have to cut blocks of program out and make them a separate function, move it out of main and that works. For a while anyway...

Im using windows XPpro, and version PCW version 5.036

Chris

asmboy · Joined: 20 Nov 2007 Posts: 2128 Location: albany ny

1- what sort of program rom / main() size are we talking about?

2- is there a time domain reason all the code is in main?
It must make for some interesting looking, fun to trace code.

3- do you merge library code directly into main() too?

jeremiah · Joined: 20 Jul 2010 Posts: 1322

In general large all in one main's are a bad idea for a variety of reasons.

SherpaDoug · Joined: 07 Sep 2003 Posts: 1640 Location: Cape Cod Mass USA

With PICs all functions including main() have to fit on a memory page. Several small functions may fit on one page but no function can cross a page boundary. If your chip has 4 ROM pages then no function can be bigger than 25% of ROM. Generally many small functions are easier for the compiler to fit on the pages.
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Arizona Chris · Joined: 20 Dec 2014 Posts: 69 Location: Arizona

Thanks Guys, I agree it is proper coding practice to use sub functions in main and not try to fit your entire program into one function. Our company policies on this are pretty standard, writing code in defined blocks as function makes it far easier for the next guy to understand and change!

I think the code crossing boundry for a main function is probably what I see occasionally. the latest one I saw this in had lots of big numbers in main ("magic numbers") that probably filled the space up without realizing it.

The more I am in tune with this program structure, the more efficient I can be in creating the best code for our line of products. Thanks again for your responses, its always a learning experience and so much fun!

Chris