Re: [Flashforth-devel] Fwd: Re: C function with more parameters in W0-W7

[Mikael N. <mik...@fl...>]

Nope, I did not see that comment.

It is of course reasonable to init data segments when you link to 
C-code.
I had unchecked that option just to save same some code space for pure 
FF compilations.

Note that FF also uses a flash area for the EEPROM emulation.
For 128 Kb and larger devices it is placed at 0x10000-0x10fff in flash.
You could place the c-code and libs at 0x11000 and up.
There is also some unused flash space in 0x10000 - RAMSIZE upto 0xffff.

For smaller devices the EEPROM emulation is placed inside the FF core 
dictionary area.


On 09.06.2015 10:08, om1zz wrote:
> Have you read my note in the Ctest.c header?  :)
>
> After some experimenting I found out following trick (my current
> undrestanding how it works):
>
> 1. you have to enable "Init data segments" in the xc16-ld settings
> 2. it puts crt0 at the beginning
> 3. after that it places all calls to .external libs/functions
> 5. after that it puts FF.s
> 6. it jumps from crt0 at the point in FF.s you marked as ".text"
> (COLDLIT/WARMLIT)
> 7. then it runs through the FF.s as usual.
>
> I have got both floats (single lib) and Ctest (9degree test function
> with double lib) placed in the segment from 0x0200 to 0x2000 and FF.s
> from 0x2000 up (see your map file).
>
> Of course, that is ok for 128kB flash parts (43kWords), but we need
> to place all the external functions somewhere above 196kB flash, as 
> it
> is my understanding FF can only address "lower 64kWords"  (what is
> still quite a lot for a forth when you can call external functions 
> out
> of it). With a 512kB dspic33EP flash parts it could be an interesting
> combination.
>
> When using double (64bit), ie. in the Ctest.c 9degree demo, you must
> enable "Use 64-bit double" in xc16-gcc settings, otherwise the double
> will work as a float only (even when declared as a double).
>