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From: antispam@fricas.org (Waldek Hebisch)
Newsgroups: comp.arch
Subject: Re: What is an N-bit machine?
Date: Sun, 15 Dec 2024 18:20:31 -0000 (UTC)
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Terje Mathisen <terje.mathisen@tmsw.no> wrote:
> MitchAlsup1 wrote:
>> On Sat, 30 Nov 2024 19:40:17 +0000, John Levine wrote:
>> 
>>> I get the impression that we will have 32 bit architectures for a very
>>> long time, since they are smaller and cheaper to implement than 64 bit
>>> and for a lot of embedded applications they are more than adequate.
>>> Examples are ARM Cortex-R4 and -R5, high performance 32 bit realtime
>>> chips.
>> 
>> Still one hardly needs more than a Z80 to run a toaster, microwave,
>> stove,
>> oven, faucet, door lock, refrigerator, ... {{Or basically everything
>> nobody
>> ever thought would have/need a computer inside of them}}
> 
> They are still going to end up with a 32-bit CPU in future products!
> 
> Both because that's needed to support a full development environment/ 
> arbitrary languages and because the cost is becoming mostly trivial:
> 
> When every single flash/thumb drive has contained a full 32-bit CPU for 
> more than 5 years now, the cost has to be in the cents range.

One can buy 32-bit Risc-V for $0.10, but CPU is integrated with RAM
and flash and you get "16-bit" amount of flash (16kB) and RAM (2kB).
IIUC compressed variant of Risc-V is rather compact, but still,
there is non-negligable space cost for 32-bit addresses, so
architecture with 16-bit addresses _may_ have some advantage
(or possibly IP16 option in compiler, but current 32-bit MCU-s
allocate address space in sparse way, making 16-bit pointers
rather inconvenient).

OTOH only highest volume applications are looking for very cheap
(< $0.10) MCU-s.  In most other cases lower cost (like Pavuk MCU)
does not compensate inconvenience of developing software.

-- 
                              Waldek Hebisch