Look up table with PIC12F683 in CCS C

[Doralice]

Hello!!

I'm working with a PIC12F683 and I'm using a CCS C compiler.
I need to allocate in program memory two look up tables, the first is declared as

const char potenz[178]={...};

The second has 256 elements, each one 16 bits length:

const int16 potenz1[256]={...};

As a result, after building, the first table is correctly allocated, but the second one is missing.

Each words in program memory is 14 bits length.

Can allocate it a table with elements of 16 bits length?

Any suggestion is appreciated!!

Thanks!!
_________________
Bugs will appear in one part of a working program when another 'unrelated' part is modified.

Doralice

[PCM programmer]

What's your compiler version ? I tried it just now, and the compiler stores
it as a ton of RETLW's. It's there. But to see it, you need to edit the
12F683.h file and comment out the #nolist statement at the top of the file.
Then re-compile and look at the .LST file. You should see the RETLW's.

Also, to see the data, you need to access the const array with a variable.
If you just access a few elements with constant indexes, the compiler
will optimize those accesses into MOVLW statements. It won't put the
whole array into Flash memory. It does this to save ROM.

[Doralice]

Good evening,
my compiler version is:
"CCS C Compiler PCM version 4.118"

I've explained below the declarations I've made inside my declaration file "potenz.h". I have to store this two look up tables in the program memory.

[Ttelmah]

It is not stored in RAM memory. What is applying is the second paragraph in PCM programmers reply. Since you are only accessing a fixed location, the compiler is 'optimising' the table away, and just storing the used value as a MOVLW.
You need a single line like:

val=potenzl[val];

where 'val' is a variable, to make the compiler realise that it can't predict what lines are needed, and it'll then store the whole table.

Best Wishes

[Doralice]

Yes,
thank you and PCM Programmer.
Now I've understood how the compiler optimizes the code in memory.
I'll try now to allocate a table with char elements and a table with int16 elements.

Doralice
_________________
Bugs will appear in one part of a working program when another 'unrelated' part is modified.

Doralice

[bells_electronics]

@ Doralice

Did you solve your issue? if yes then how?