Re: What Is The Difference Between 68000 Chip And 80x86 Chip?

["OneLouder" <edayaxwellmay@exoboxway.omcay>]

> What Is The Difference Between 68000 Chip And 80x86 Chip?
>
>     I have studied 6502 and 65816 microprocessor.  I am wondering about
8080
> or 8088 microprocessor.  Are both 65816 and 8088 microprocessors very
> similar, but they have different hex code for each opcodes?
>     Why do PC prefer 80x86 microprocessor such as Intel/AMD?  Also why do
> Macintosh prefer 68000 microprocessor such as Motorola?  What is the
> difference?  Which is the powerful?  I bet that Motorola microprocessor is
> much easier than Intel microprocessor.  Please advise.

Wow.  This is a rather complicated subject.

In general, the evolution of mainstream microprocessors followed two
different paths - the Motorola 6800/6809/68000/68020/68030/68040, roughly
based on DEC's elegant designs for the PDP-11, and the Intel
4004/8008/8080/8086/8088/x186/x286/x386/x486/Pentium path, which tended
toward non-orthogonal instruction sets with specialized registers, closer to
the original IBM-type computers.

The 68K design tended to use a large number of similar registers, and
addressing modes that worked on all of them, and had a single 32-bit address
space (although the 68000 was limited to actually 24-bit).  The x86 designs
tended to use a smaller number of specialized registers, and addressing
modes that only worked on certain registers, and had a segmented address
space, although that was changed in later versions.

Take the 6502 for example - you can add an immediate value to the A
register, but not to the X and Y registers.  In the 68K way of doing things,
all three would be able to do the same things.

In general, I think purists would say the very orthogonal Motorola design
was easier to write software for, particularly software generated through
compilation.  On the other hand, Intel was very aggressive with
manufacturing and marketing, and, in a fateful decision we all live with
today, won the all-important design win with the IBM PC int he early 1980s.
Note that IBM almost chose Motorola, but Intel was able to show they had the
manufacturing capacity that Motorola didn't have to meet the expected
demand.

Note that the Macintosh no longer uses the Motorola 68K family, but rather
the PowerPC RISC processor - another entire subject.

With a little googling, you'll find many resources of the web that discuss
this further.