Re: problem using FILE pointer

On Sat, 14 Feb 2009 22:34:38 -0600, 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.

Also, how should the 68008 be classified with 8 bit external data bus
and 32 bit instruction set ? The 8088 had 8 bit external data bus but
internally 16 bit addressing.

From the compiler code generator point of view, these are the same as
their wider brothers, although the number of external address lines
might be smaller, but this should not affect the code generator.

Paul

.

Relevant Pages

  • Re: How to develop a random number generation device
    ... chip, and something new will be required to manage them. ... a single ALU can look like two slightly slower ones. ... Not register banks, just a couple of bits in the rename register ... extra hardware for an FPU for each CPU. ...
    (sci.electronics.design)
  • Re: problem using FILE pointer
    ... The instruction set ... architecture and basic register width are what counts - it was 32-bit ... IMO the ALU width defines the chip, but I won't debate that here. ... question was a 4-bit CPU. ...
    (comp.arch.embedded)