Pointer to function problem

[smanzer]

Good morning,

I have found an interesting challenge when trying to run functions when using a structure containing a function pointer. I have read everything I can about work arounds on this forum and although the posts have helped I am still having trouble.

The pic is a 18F8722, compiler is 4.093.

I have many include files as part of a home automation system. The program is becoming quite large with ROM=73% and RAM 35-44%

When I call the menu routine to save the function pointer to be called I get a pointer value that is beyond $FFFF for example $0104B2. Looking at the .lst code shows that that is where the function resides. I modified the code as suggested by PCM_Programmer to make it a 16 bit variable, but this is a 17 bit number. So, I changed it to a 32 bit number.

The function never runs. It is only the functions that have a 17bit pointer that do not execute. Here is how the function is called when using a pointer to the function that is stored in a structure:

[PCM programmer]

My first thought is to use #org to put anything that involves function
pointers into the first 64KB of Flash.

[smanzer]

Thanks PCM_Programmer, that should work! I have a variable that I use to turn on/off debugging info to the pc terminal. When I turned it off, the program size dropped so the offending functions were in the first 64K and it all worked as expected.

I have never used #org, would this be correct for an 18F8722:

#org 0x0000, 0xFFFF

Looking at the data sheet, it looks like On-Chip Program memory goes from 0x00000 to 0x1FFFF, there are Reset Vectors and Interrupt vectors from 0x0000 to 0x0018, do they have to be excluded like:

#org 0x0018, 0xFFFF

Thanks for helping again PCM_Programmer!!

Steven
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