Zilog System 8000 Model 31 available in Australia

From: ben franchuk <bfranchuk_at_jetnet.ab.ca>
Date: Fri Nov 22 12:19:00 2002

Hans Franke wrote:

>>I guess with Big Brother Intel the best processor designs
>>like the 6809 and the PDP-11 are the odd ones.
>
>
> Hmm... I have a hard time to agree here. The 8086/7/9 is
> to me one of the best CPU designs ever - at least for a
> true 16 Bit machine. I true atempt to brng the good parts
> of mainframe design to microprocessors.

The problem is that 8086 is not a clean 16 bit processer
but rather a 8 bit load/store architecture ( 8008/8080)
with 16 bit and CISC instructions tacked on. The 8008/8086
was ment to be one family of chips, with real 16/32 bit
processing by another family of chips that totaly bombed.

> Ok, if we just look at the CPU, then the 9900 will catch
> the title for beeing a true 16 Bit design

The other thing people forget is 8 bit bytes really screwed up
computer architecture. Where a 16 old bit machine like
say the IBM-1130 could have effective accumulator/memory
architecture the loss of 1 bit of addressing and opcode
length because of bytes and indexing neededs to scaled
requires now a register/register architecture like the
PDP-11.

In hindsight we now know that 16 bits is too small a
addressing range for a general purpose byte/word cpu's
and only expanding to split code/data and other memory
management tricks could one have useful machine. Lets
not forget video graphics too only took off with large
addressing space too. Remember CGA !!! 16k of memory.

> Gruss
> H.

Ben.
Received on Fri Nov 22 2002 - 12:19:00 GMT