[avr-gcc-list] Porting code to/from codevision

[Peter Harrison]

Hi

I have recently started to experiment with WinAVR with a view to moving 
my code from CodeVision. I have no problem with CodeVision and have 
found it a delight to use but I want the code to be available without 
expecting the user(s) to pay for a commercial compiler. Equally, a user 
with CodeVision should not be disadvantaged either.

Well, I got most stuff done and sorted out the hardware access and, as 
far as I can see, the AVRGCC way of doing IO will work unchanged on 
CodeVision. My application compiles and links just fine and will run 
under AVR studio.

Now, the question of how to deal with data in flash arises. I can redo 
the code to make sure that things like bitmaps, lookup tables and menu 
strings all sit neatly in flash. CVAVR, of course makes this trivial by 
recognising the location of data and generating suitable code.

My question, at last, is: Does anyone have pointers to how I might best 
arrange things so that the code will compile both in AVRGCC and CVAVR - 
or am I better not trying?

Specifically, I have a largeish lookup table (4k) and menu data (titles, 
function pointers etc) to deal with. I have considered using a macro for 
the data access so that I can write

value = READ_FLASH_BYTE(addr);

and define the macro as null in CVAVR or as required by AVRGCC. However, 
I am less sure about the declarations and can't get my head round a 
suitable dodge.

Just to make things more awkward, I may well want this code to compile 
with the ARM and H8 GCC compilers. On the PC, I simply have a macro that 
defines 'flash' as null and the code compiles just fine.

Is this overdoing the portability thing?

Pete Harrison