Graphically impressive z80 machine

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Por Pentarou

Master (223)

Imagen del Pentarou

31-10-2018, 23:37

Edevaldo wrote:

Or more likely the opposite. They had Z80 licensed because they were using it in their machines and their chip customer were also using it.

Who knows? Seems like a chicken and egg problem.
It could be as you said for SHARP, but NEC Z80 clones were on the market before their PC600* was released.

Por hit9918

Prophet (2867)

Imagen del hit9918

01-11-2018, 17:47

the NES and PC Engine got NO 6502 cpu but got the 6502 in the chipset!
so, it was not used because one prefered it over the z80 but because it has lower transistor count.

Por TomH

Champion (327)

Imagen del TomH

01-11-2018, 18:47

hit9918 wrote:

the NES and PC Engine got NO 6502 cpu but got the 6502 in the chipset!
so, it was not used because one prefered it over the z80 but because it has lower transistor count.

That's easy to believe; it's the same reason there's one in the Atari Lynx.

Por Edevaldo

Expert (128)

Imagen del Edevaldo

01-11-2018, 19:29

Quote:

Who knows? Seems like a chicken and egg problem.
It could be as you said for SHARP, but NEC Z80 clones were on the market before their PC600* was released.

Knowing as semiconductor business goes, and particularly in Japan... It is pretty safe to assume they had a market for it before they commit to producing it. Z80 should already be a high volume sales device in Japan at the time. And they know that Japanese customers strongly prefer to buy from Japanese suppliers. So they would have a guaranteed market for it.

Por Edevaldo

Expert (128)

Imagen del Edevaldo

01-11-2018, 19:30

Quote:

the NES and PC Engine got NO 6502 cpu but got the 6502 in the chipset!
so, it was not used because one prefered it over the z80 but because it has lower transistor count.

Good point.

Por tvalenca

Paladin (728)

Imagen del tvalenca

28-12-2018, 16:21

TomH wrote:
PingPong wrote:

It's a 16 bit processor. IMHO we are out of the comparison.
they used the 65816 because of the compatibility with 6502

Well, for relaxed definitions of a "16-bit" processor, anyway, being a fairly meaningless term.

One processor has an 8-bit data bus, 16-bit address bus, an 8-bit primary accumulator, can perform 8- and 16-bit arithmetic, and does so with a 4-bit ALU. Obviously, it is 8-bit!

Another has a 16-bit data bus, 24-bit address bus, a suite of nearly-orthogonal 32-bit registers, and primarily performs 32-bit arithmetic using a 16-bit ALU. Obviously it is 16-bit! Unless you're talking about the version with the 8-bit data bus. That's 8 bit, obviously.

Yet another has an 8-bit data bus, 24-bit address bus, 8-bit primary accumulators, and performs 8- and 16-bit arithmetic, with a 16-bit ALU. It's 16 bit, of course!

A fourth that springs straight to mind has a 32-bit data bus, a 26-bit address bus, and an orthogonal set of 32-bit registers with a 32-bit ALU. This one is 32 bit!

So the rule is: classify as whatever the marketing department picks. After all, it's not the ALU, the primary register size, the data bus size, the usual data word size or any function of the address bus size.

I prefer the Accumulator register approach: it is the smallest data needed to perform an operation. so:

Z80 = 8bit
68000 = 16bit (68008 is also 16bit)
8088 = 16bit
80386 = 32bit.

Did I got right? Or did I missed any?

Oh, and of course: 6502 = 8bit and 65816 = 16bit. And R800 = 8bit. (ducking under the desk)

Por keith56

Master (152)

Imagen del keith56

30-12-2018, 10:53

All the registers on the 68000 are 32 bit... not sure how you would count the accumulator as 16 bit.

Por sd_snatcher

Prophet (3068)

Imagen del sd_snatcher

30-12-2018, 15:28

On the Z80, the HL is used as a 16bit accumulator by many instructions. Would this then make it a hybrid 8bit/16bit? Running Naked in a Field of Flowers

Por tvalenca

Paladin (728)

Imagen del tvalenca

31-12-2018, 13:14

keith56 wrote:

All the registers on the 68000 are 32 bit... not sure how you would count the accumulator as 16 bit.

you're right. I've messed this because of the 16-bit ALU.

Por tvalenca

Paladin (728)

Imagen del tvalenca

31-12-2018, 13:15

sd_snatcher wrote:

On the Z80, the HL is used as a 16bit accumulator by many instructions. Would this then make it a hybrid 8bit/16bit? Running Naked in a Field of Flowers

nice try! Smile

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