[fpc-devel] M68k: important milestone reached
mschnell at lumino.de
Mon Feb 24 14:22:22 CET 2014
On 02/24/2014 01:42 PM, Sven Barth wrote:
> You could either write a custom heap manager (similar to cmem which
> simply calls malloc/free from the C library), but you'd still need to
> keep the initial heap usage for initialization of the system unit in
> mind (except you replace the default heap manager functions inside the
> system unit). Otherwise you'd need to implement the SysOSAlloc and
> SysOSFree functions usually located in $fpc/rtl/OS/sysheap.inc (for
> Linux the location is $fpc/rtl/unix/sysheap.inc) to get the heap to
> use your C library functions.
Thanks for all these useful hints.
As the heap needs to be shared between the C functions and the Pascal
functions I suppose I should just implement the SysOSAlloc and SysOSFree
functions i a new "embedded" RTL and call the appropriate C RTL
functions there. And yes, I do multithreading. The C RTL heap handling
functions already are thread save, so no problem here. I suppose the
string handling needs additional thread awareness, but as - at least at
this point in planning - the use of Pascal is restricted to a single
thread, this should not be a problem.
> That's good. That's the same ABI that Linux uses.
This is what I expected. I forgot to mention that the result of a
function is returned in D0. But I a positive that this is the same in
Linux as well.
>> FPC itself does not need to care for MMU or no-MMU. ;)
Great. So the FIDO will be compatible with 68020 (e.g. can do 32 Bit
offset with BCC)
>> What do you mean with the "binutil API"?
Am I wrong to assume that "binutil" also provides some library functions
to include in the to-be-compiled project (e.g. "prototypes" for calling
stuff in glibc) ?
In fact I do not really understand why I need to have binutils just for
creating a .o file that is to be linked into a C project.
> Yes, currently FPC can not generate m68k PIC code, so something like
> that will be necessary.
I did assume this ;-) .
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