constant array problem !

[ROBOTICAR]

Hi all.
I want to print constant array but not directly and in main(). ! In this code I used pointer and I think print_data() work while I define F8_18 in RAM.
my question is here : why I can't get result correctly ?
(I think i must use read_program_memory() . am i right?)

[collink]

Yeah, you should use read_program_memory. The below should work for you:

[Ttelmah]

No.....

Problem is that when you store a constant array in memory, it _does not_ start at the beginning of the area declared to hold it. The compiler places the program to retrieve the values here, followed by the values themselves.

There are a number of answers acccording to what you really need.

First, the function 'label_address', will return the actual address in memory where the array is stored. You can then use 'read_program_memory' starting at this location to access the data.
In fact the array won't fit in the area declared, because of this extra code....

Second though, if you store the array using #ROM, rather than 'const', the array will be placed directly in the program memory, without the access code.

Third thing though is that on the latter compilers, you can use pointers to an array declared like this....

So the original code, won't compile, since the array + access code, won't fit in the area defined (remember you need #org default after the array to switch the memory useage back to normal....).
The 'answer' won't work, because you can't hand the address of the array like this, and the read_program_memory function, does not return a value, instead requiring an _address_ to put it's result into.

Simplest answer, use rom, instead of const, get rid of the ORG statement, and let the compiler handle things for you.
Other answer, enlarge the space enough for the extra code, use 'label_address' to get the memory address involved, and hand this as a simple int16/32 (depending on the processor memory size), to the function.

Best Wishes

[collink]

Whoops... I guess I should have mentioned that. I do use #DEVICE CONST=ROM in my code. Also, I was mixing up read_program_memory and read_program_eeprom. read_program_eeprom works the way I showed.

[Ttelmah]

I actually don't like using 'CONST=ROM'. I think it is better to use the ROM keyword, and keep 'const' with it's normal meaning. Having multiple meanings to one keyword, is asking for problems latter with working out what is going on...

However, using this (either const=ROM, or int8 rom as the data declaration), then you can use: