[fpc-pascal] MS DOS 8086 compiler?

Marco van de Voort marcov at stack.nl
Sun Apr 28 16:14:02 CEST 2013

In our previous episode, Mark Morgan Lloyd said:
> > 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:
> OK, answering my own question then. A pure-8086 port could be valuable 
> if it generated reliable code for something like vtprolog.pas, since 
> this implements its own garbage collection relying on detailed knowledge 
> of how Turbo Pascal manages its heap.

Heap management is mostly a RTL feature. For high TP compatibility, things
like calling conventions must also match.

IOW 8086 codegeneration is not automatically full TP compatibility on the
binary level.

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