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From: Lawrence D'Oliveiro <ldo@nz.invalid>
Newsgroups: comp.sys.raspberry-pi
Subject: Re: OT: horrible 8086 segmentation
Date: Mon, 23 Dec 2024 22:55:52 -0000 (UTC)
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On Mon, 23 Dec 2024 03:26:11 +0000, Brian Gregory wrote:

> On 18/12/2024 06:22, Lawrence D'Oliveiro wrote:
>
>> On Sun, 01 Dec 2024 15:11:05 +0000, Richard Kettlewell wrote:
>> 
>>> The Natural Philosopher <tnp@invalid.invalid> writes:
>>>
>>>> I also remember a zilog Z8000?
>>>
>>> Yes, although also with a segmented memory model.
>> 
>> Its segmentation scheme made Intel x86 look good.
> 
> Not that unusual. Compare to some of the Microchip PICs. Some have
> really bizarre bank switching arrangements and so on.

I think the Apple II RAM expansion card worked by switching to a different 
bank (48K each?) every time a particular control register byte was 
written. You couldn’t just write a bank number: instead, you had to repeat 
the write N number of times, and I guess remember where you started from, 
to get to the right bank.

But this was because the CPU itself only supported 16-bit addressing. What 
was Zilog’s excuse?