Meaning of "architecture width" - Re: 68K Macs with MacOS 7.5 still in production use...

[Toby Thain]

On 2016-09-16 2:32 AM, Camiel Vanderhoeven wrote:
> Op 15 sep. 2016 11:57 p.m. schreef "Toby Thain" <toby at telegraphics.com.au>:
>>
>> On 2016-09-15 2:38 PM, Noel Chiappa wrote:
>>>
>>>     > From: Chuck Guzis
>>>
>>>     > Call it anything you want, but we know what Motorola called it.
>>>
>>> The _first implementation_ may have been 16-bit, but I am in no doubt
>>> whatsover (having written a lot of assembler code for the 68K family)
>>> that the _architecture_ was 32-bit:
>>>
>>> - 32-bit registers
>>> - many operations (arithmetical, logical, etc) defined for that length
>>> - 32-bit addresses
>>
>>
>> GPR width, being the visible programmer model, is the most common and
> convenient definition of "architecture" I've come across. But there's no
> reason we can't just say the *visible* architecture is 32 bit (which it
> is), but the "internal" architecture is sort of 16.
>
> Afaik, the term computer architecture was coined for the IBM 360, which was
> a 32-bit architecture, with 8, 16, 32, and 64 bit implementations. The term
> architecture specifically refers to what the programmer sees, not to the
> specifics of an implementation.

Yes, and that's the meaning I'd default to.

--Toby


>
> Camiel
>