[fpc-pascal] DOS compiler wiki page: please review

Nikolay Nikolov nickysn at users.sourceforge.net
Sun Oct 6 22:37:44 CEST 2013

On 10/05/2013 03:07 PM, greim wrote:
> Hi,
> writing a 8086 version of fpc is not so strange as some may think!
> There are still some 80186 processors around running in embedded 
> systems! These architecture is certified for some applications in 
> industrial and avionik controll.
> ....
> So my wish list:
> fpc for 80186, supporting the new extended addressing and writing the 
> header files for RTOS (see 
> http://www.beck-ipc.com/en/products/rtos/index.asp) incl. a FPU 
> emulation !
 From what I read from the links you posted, the extended addressing 
seems to be just like the regular real mode, except that segments are 
spaced not 16, but 256 bytes apart, is that correct? If that's the case, 
it should be easy to support - it's just a matter of writing the RTL for 
the new OS and using the appropriate linker. FPC for i8086 produces 
object files in the standard ROMF file format, they just use the 
extension .o, instead of .obj. Note that FPC currently only supports the 
tiny, small and medium memory models. Compact, large and huge are 
planned, but not started yet. But you can try writing an RTL for RTOS 
with the current memory models. In principle, it shouldn't be any harder 
than porting the compiler to any new OS, where the CPU is already 
supported. And when I implement the compact/large/huge memory models, 
the RTOS RTL will have to be adapted to support them. Most likely, the 
far heap manager (which doesn't exist yet) will have to be adapted to 
support the different spacing between the segments. As for FPU 
emulation, it is also on my TODO list :)


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