29 Jan
2011
29 Jan
'11
9:32 a.m.
Dwight wrote:
My first thoguht was of a slightly larger HP calculator, the 9800 series.
[...]
I always thought is would be fun to make a
variable
bit serial computer. Many operations only need a single bit
while the single bit ALU could operate on data, like
adding, one bit at a time and use any length one wanted.
Chuck Guzis wrote:
How about instead of bits, 4-bit digits (perhaps
with a programmable
switch between BCD and binary math)? I suspect that it wouldn't be
much more complicated than 1-bit serial design.
You've just described the architecture of the proprietary processors
used in Hewlett-Packard calculator models released between 1972 and 1999. Classic: 56-bit, BCD only, strict Harvard
architecture (10-bit ROM
words in separate address space)
Woodstock/Spice/Topcat: 56-bit, selectable BCD/binary, strict Harvard
architecture, 10-bit ROM
The HP919C must be in this group too (same ACT processor), what about the
other Sting model, the 10A? And of course the 67 uses an ACT too, even
though it's sometimes clased as a 'classic series' by people who think
the case is nor interesting than the procesor :-)
-tony