20 Oct
1999
20 Oct
'99
10:01 a.m.
Eric Smith wrote:
If you didn't use a bit-slice, you'd have to use separate ALU, memory,
and shifter chips, and you'd wind up with even more.
The early microprocessor architectures were designed based on minimal
transistor count for a single-chip implementation. This does not result
in minimal chip count if you implement the equivalent in 7400-series
chips. It is quite possible to design useful processors with a lot fewer
TTL chips.
FYI-> The 7400 series ALU-chip (4bit) is the 74181
Another way to go would be to use EPLD or a programmable ASIC chip. I
have heard stories of a Pr-Asic 486-clone "program" being aviable. Does
anyone know anything about this.
I've also been thinking about "cloning" a kinda 32bit clone of the
famous
TMS 9900. This chip had it's registers in memory and if such a design
would incorporate cache memory the results would still be respectable.
Especially if it could be done with programmable-asic technology.
Sipke de Wal