[Coco] Kicking the Z-80 butts...

[CoCo Demus]

This is so arbitrary, the 6309 has 32-bit manipulation but this means
nothing. For me the direct memory addressing is the best indicator of
processor type:

64K : 8-bit
1M-24M : 16-bit
24M-4Gb : 32-bit
>4Gb : 64-bit




On Tue, Apr 28, 2015 at 4:06 PM, Hugo Dufort <hugo at seshat.ca> wrote:

> I've always found this "8-bit vs 16-bit classification" debate quite
> strange.
> Most processors of the early late 1970s to early 1980s era had a mostly
> 8-bit structure. Their working registers and most operations were mostly
> 8-bit.
> Sure you have a D register on the 6809, but most operations (especially
> bitwise operations) are strictly 8-bit (A, B). The joint A:B=D register is
> necessary to use the multiplication results, for instance, or to manipulate
> memory addresses.
> Having a joint 2x 8-bit register (A:B=D) and 3x 16-bit address registers
> don't qualify as "16-bit computing" in my opinion.
> You can't perform much accumulator-like operations on X,Y and U. Except
> for LD, ST and LEA.
>
> And if you look at true 16-bit processors such as the M68k, they all had a
> few 32-bit operations, as well as 32-bit "joint" registers, but that don't
> make them "32-bit processors".
>
> It is the same for all generations of processors.
>
> Hugo
>
> Le 2015-04-28 15:49, Dennis Bathory-Kitsz a écrit :
>
>> On Tue, April 28, 2015 9:24 am, CoCo Demus wrote:
>>
>>> Who needs a Z-80 anyway ???
>>>
>> Ha! Okay, can I bit?
>>
>> It's kind of an unfair comparison as the 6809 is really a 16-bit machine
>> on an
>> 8-bit bus. Take out those 16-bit structures and you're pretty much left
>> with a
>> 6502 -- the most elegant processor of all time, I think.
>>
>> My first published article was in "Byte" in 1979: "Relative Subroutines
>> for
>> the Z-80", emulating the 6502's behavior.
>>
>> Now give a Z-80 a 16-bit internal structure...
>>
>> No, don't answer me! :) :)
>>
>> Dennis
>>
>>
>>
>>
>
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