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jotd · 22 November 2020, 18:21

ok, looks like the program is still needed. And I have started coding it and not far from completing it.

I would seem that the boot code could be destroyed by relocating onto itself, which is pretty tricky to handle. A proper reloc routine would start by setting a routine in high memory, then this routine copies the data (respecting the direction of the copy depending on how the source & destination are in memory).
But prior to that it would have to disable all interrupts, because the OS could use this memory and crash.

So it's not that trivial to code if you want it to run on a 1MB chipmem / no fast machine.

22 November 2020, 18:21	#23
jotd This cat is no more Join Date: Dec 2004 Location: FRANCE Age: 49 Posts: 4,936	ok, looks like the program is still needed. And I have started coding it and not far from completing it. I would seem that the boot code could be destroyed by relocating onto itself, which is pretty tricky to handle. A proper reloc routine would start by setting a routine in high memory, then this routine copies the data (respecting the direction of the copy depending on how the source & destination are in memory). But prior to that it would have to disable all interrupts, because the OS could use this memory and crash. So it's not that trivial to code if you want it to run on a 1MB chipmem / no fast machine.