Re: problem using FILE pointer



On 2009-02-15, Dennis <dennis@xxxxxxxxxxx> wrote:
George Neuner wrote:
On Fri, 13 Feb 2009 11:04:58 +0100, David Brown
<david@xxxxxxxxxxxxxxxxxxxxxxxxxxxxx> wrote:

The 68K support is a different story. The 68K family has always been
32-bit, not 16-bit. It has some 16-bit features - a 16-bit external
databus, and the original 68000 used a 16-bit wide ALU (running twice
for 32-bit operands). But these are minor implementation details,
trading speed against cost and chip size. The instruction set
architecture and basic register width are what counts - it was 32-bit
from its conception.

IMO the ALU width defines the chip, but I won't debate that here.

Hmm The IBM System/360 Model 30 (mid 1960's 32 bit mainframe) had an 8
bit ALU. Of course that was back in the day of real microcode. And it
was much more than a single chip.

I once used a processor which I and most other people would
call a 16-bit processor (16-bit registers, 16-bit address
space, 16-bit data paths). However, it was built out of a set
of AM2901 bit-slice processors. Since each of the AM2901 ALUs
was 4-bits wide, I guess George would say that the CPU in
question was a 4-bit CPU.

There were some pretty famous CPUs built using the AM2901
family: DEC PDP-10, DG Nova, AN/UYK-44, and so on. All of them
4-bit CPUs, presumably.

--
Grant

.



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