Re: Keeping other stuff with addresses

Tim Rentsch wrote:

Thomas Koenig <tkoenig@netcologne.de> writes:
 

I think "ALU can add up to n-bit numbers" is a reasonable definition
for an n-bit architecture, which also fits the 16-bit 68000.
It does not fit the 360/30, or the Nova (but see de Castro's remark
on the latter).

 To me, the phrase "n-bit architecture" should depend only on such
characteristics as are defined by the architecture, and not depend
on features of a particular implementation.  The 360/30 has a 32-bit
(or is it 64-bit?) architecture, but only an 8-bit implementation.
 If I may add a personal note, it's disappointing that postings in a
group nominally devoted to computer architecture routinely ignore
the distinction between architecture and implementation.  I don't
mind comments about matters of implementation, but the constant
blurring (or erasing) of the line between architecture and
implementation often makes it nearly impossible to have a discussion
just about architecture.

I agree!
The one exception which I personally find OK are discussions of what happens when an implementation is so bad that it effectively removes the architecture feature from programmer consideration.
I.e. having architectural string/memcpy instructions that are much slower than sw implementations, for several decades.
Terje
--
- <Terje.Mathisen at tmsw.no>
"almost all programming can be viewed as an exercise in caching"