Re: What is an N-bit machine?

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.

--
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