Re: [avr-gcc-list] ATMega640/ATMega641/ATMega1280/ATMega1281/ATMega2560/ATMega2561

[Bjarne Laursen]

Chip Webb wrote:

> It seemed as though there were two proposed methods to handle this:
>
> 1) Align functions (and labels?) to 4-byte boundaries so that  gcc can 
> continue to use 16-bit
>   values to represent function pointers.  This isn't so different from 
> the method that is
>   already used for the Mega128.
>
> 2) Modify GCC to support longer pointers (PSImode?)

3) Make any function, where the address is put into a pointer, start  
below 64K, using a jump if neassesary.

Also: If these functions, and any program memory strings could be forced 
into a memory range like 32K<=adr<64K, it would be possible to determine 
if a pointer points to ram or flash at runtime. This could be very useful.

I know these things have limits too, like when using more than 32K ram, 
or more than 32K program memory strings.