Running Out of Programing Memory

[Jerson]

One thing that will save you a lot of code is replacing repeated segments of code like for example - SEROUT ..... or LCDOUT. So, if you have a LCDOUT "Hello World" maybe 5 times in your code, it would be better to replace 4 of them with a gosub ShowHelloWorld and keep the LCDOUT "Hello World" in that subroutine.

[rsocor01]

Jerson,

Yes, I already use a lot of sub-routines.

Melanie,

Using the BANK0 next to the variables declarations didn't help. I think that I read somewhere that newer versions of PBP already take care of this BANK issue. However, moving sub-routines to the beginning of the program after the variables declaration help me free about 60 words.

Ioannis,

The link that you provided was very helpfull. I used in my program a lot of (with different variables all the time)

IF (VAR_0=0) AND (VAR_1=1) AND (VAR_2=2) AND (VAR_3=3) THEN
   ........
ENDIF

IF (VAR_0=0) OR (VAR_1=1) OR (VAR_2=2) OR (VAR_3=3) THEN
   ........
ENDIF

And according to the link that you posted you can save a lot of space by changing the above lines by

IF (VAR_0=0) THEN
   IF (VAR_1=1) THEN
      IF (VAR_2=2) THEN
         IF (VAR_3=3) THEN
            ........
         ENDIF
      ENDIF
   ENDIF
ENDIF

IF (VAR_0=0) THEN ........
IF (VAR_1=1) THEN ........
IF (VAR_2=2) THEN ........
IF (VAR_3=3) THEN ........

Well by using this technique I was able to go from 8118 words down to 7216 words. Enough to do what I need to finish my project. It would be nice to see an improved version of this link here in this forum. I'm sure that there are many techniques and tricks to save a lot of space that we don't know about.

Robert

[Ioannis]

I am glad it helped.

The best way to reduce size is to do it in ... assembly.

Ioannis

[BrianT]

Each ASCII character included in a SEROUT, LCDOUT, DEBUG or SEROUT2 takes at least two characters in program memory for each ASCII character in the string.

Keep any user prompts as terse as possible.

HTH
BrianT

[Charles Linquis]

This brings up an issue that I have long harped on.

Unless you are building a huge quantity of something, where the cost of the coding can be amortized across a large number of units, ALWAYS

Use an 18F part
Use a part that has at least twice the codespace you need.

And, if you want to know if you have exceeded any particular memory size, use

ASM
     ORG 0x1fcee        ; put your limit here
     nop
ENDASM

at the end of your program. The compiler will give you an error if you exceed the size given in the ORG statement.

[rsocor01]

Hi all,

Thank you all for your help. This post is an update for this thread. When giving the final touches to my program, I found out one more time that I was running out of programming memory space. Luckily, I was able to reduce the size of my program by almost 1K words . I don't know assembly so; this is how I did it.

Before, I was using only one variable I that was declared as a word for all my FOR I = ... NEXT I loops and whenever I needed a counter I = I + 1.

I VAR WORD

Sometimes the value of I went well over 255 but must of the times it didn't go over 255. So, I created a new variable J and declared it as a byte.

I VAR WORD
J VAR BYTE

I replaced J by I wherever it was possible and BINGO, the size of the program went down by almost 1K words.
Again, Thank you all for your help.


Robert

[Ioannis]

Also a 0 to x instead of 1 to x may help too in a for-next loop.

Ioannis