| Re: What microprocessor is more powerful, the Z80 or 6502? [message #368931 is a reply to message #368889] |
Mon, 11 June 2018 16:26   |
hancock4
Messages: 6746
Registered: December 2011
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On Sunday, June 10, 2018 at 12:06:28 AM UTC-4, Quadibloc wrote:
> On Saturday, June 9, 2018 at 9:59:53 PM UTC-6, barry...@yahoo.com wrote:
>
>> Maybe we all have a different point of view regarding the definition
>> of "powerful".
>
> That could be.
>
> But the Z-80 had extended instructions that other 8-bit microprocessors did not:
> block copy, byte search, 16-bit arithmetic instructions.
>
> While the Z-80 had a lot of fancy features, though, the 6809, which came along
> later, would have been significantly more powerful yet - as it had a hardware
> *multiply* instruction, even if it wasn't crammed with as many bells and
> whistles as the Z-80, most programs would run considerably faster on the 6809 as
> a result of that.
Excellent points. Asking which is "more powerful" requires context
to make the question proper. So many questions in computers are
answered by "In Depends". This has gone back to since when computers
were first invented--different computers were designed to run best
with different applications. To this day, while a great many computers
are general purpose, there still is a need for certain specialty
machines for specialty applications, such as the supercomputers
used at Los Alamos.
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| Re: What microprocessor is more powerful, the Z80 or 6502? [message #368933 is a reply to message #368890] |
Mon, 11 June 2018 16:35 |
hancock4
Messages: 6746
Registered: December 2011
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On Sunday, June 10, 2018 at 12:15:10 AM UTC-4, Jon Elson wrote:
> Andreas Kohlbach wrote:
>
>> Back in the late 70s and mid 80s you could chose between a Z80 and 6502,
>> when it came to 8-bit home computers. Sure there where some micros using
>> a M6809 (almost 16-bit) and some 8080 CPUs. But most of the micros then
>> ran a 6502 or Zilog Z80.
>>
>> Which one is more powerful, not regarding custom chips taking load off the
>> CPU, like early "GPUs" chips in the Commodore 64?
>>
>> I say the Z80 was. It could pair some 8bit registers to 16bit
>> entities. It also already had some kind of primitives like the later 8086
>> and all future microprocessors had the 6502 lacked, speeding up things
>> and made programming in assembly easier.
> Yes, the Z80 had a lot of extra features related to handling 16-bit values.
> You could do some 16-bit arithmetic, it had 3 16-bit index registers that
> could be used as pointers to memory.
>
> One instruction group I used a lot was the INIR/OUTIR group. You could set
> one of the 16-bit registers as a memory pointer, and one as a counter, and
> then execute one of these instructions. By manipulating the WAIT signal,
> you could have it transfer an arbitrary number of bytes from one I/O
> register to a block of memory. It was essentially a CPU-driven version of
> DMA, with no extra hardware needed. I used it in mag tape controls, SCSI
> disk interfaces and a bunch of other places. No other 8-bit CPU had a
> feature like this.
In reading the detailed descriptions above the innards of the
respective chips, the manual for the IBM 603 electronic calculator
comes to mind. This manual, available on the IBM website, describes,
in detail, the circuitry and functionality of the machine. Worth a
look. (The 603 was IBM's first mass produced electronic calculator,
a predecessor to the very popular 604.)
https://www.ibm.com/ibm/files/D165357D44082B98/us__en_us__ib m100__603calc__603_manual.pdf
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