[fpc-pascal] MS DOS 8086 compiler?

[Nikolay Nikolov]

On 04/28/2013 12:00 PM, Mark Morgan Lloyd wrote:
> Bart wrote:
>> On 4/27/13, Reinier Olislagers <reinierolislagers at gmail.com> wrote:
>>> Noticed that an 8086 branch was merged to fpc trunk. Is it time to get
>>> out some 5.25" diskettes[1]?
>>>
>>> [1] Shame I dumped all the accompanying hardware long ago ;) Perhaps
>>> break out DOSBOX ;)
>>
>> I still have a portable (ahum, > 5 kg) IBM XT with 5.25" floppy disk.
>> HD is appr. 10 MB (decaying...)
>> Problem of course wil be to get the compiler on the floppy disks, and
>> then hope my HD is large enough.
>>
>> (It cost about 10,000 Dfl (appr 4,500 € / $ 5000) at the time of 
>> purgase.)
>
> I've definitely got at least one system around older than a '386, but 
> if it really is supposed to be an 8086 target it would have to be 
> tested on an 8086/8088 because of extra opcodes that were added to the 
> 186/286. I think I've got a system with 8086 or possibly V20, but it's 
> non-PC and I don't know where its copy of DOS is (it usually ran CCP/M).
>
> I don't know how reliable a test something like Dosbox or Bochs would 
> be, some of them vitualise the underlying hardware while others are 
> sloppy about what opcodes they actually implement.
>
> So in practical terms, a strict 8086 port is probably untestable. But 
> why would anybody want to when even embedded processors are based on a 
> newer architecture?
Actually, I have a vintage IBM PC 5150, with a 4.77 MHz 8088 processor, 
so this isn't true, it's very testable actually :) However, the i8086 
code generator still generates some 186/286+ instructions, so it doesn't 
work there yet, but I'm planning to fix this shortly. Here's a video of 
a few very simple Free Pascal compiled programs on a true 80186:

https://www.youtube.com/watch?v=wscin9RUiTU

(sorry for the shaky camera)

And here are the same programs, running on Charlie's (Karoly Balogh) 
Amiga 2000 with a A2286AT expansion card for PC emulation, which 
contains a real 286 CPU:

http://charlie.amigaspirit.hu/screenshots/a2000/A2000-FPC-8086-01.png

and up to -07.png

Here's the 286 card: http://amiga.resource.cx/exp/a2286at

Nikolay