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I think he had a 6.5MHz clock, the 3.25 being derived from it for the processor.
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Yes, that bit makes sense. I think computers of the day tended to have the cpu on one clock cycle, the graphics chip on the next. It's just the speed that surprises me.
Regards,
Rob Philpott.
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Just checked and it is also documented in the English wiki. My source was a French site for Vintage computing technology.
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The 6502 was a RISC CPU running at max 1MHz and you can think an average of 2-3 cycles per op.
The Z80A was more a CISC CPU running at max 4MHz.
Let's say the Z80 was a bit more sophisticated and easy to program than the 6502, which was much like a bunch of raw flip-flops...
Just kidding: loved 6502!
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Mario Vernari wrote: The 6502 was a RISC CPU
Urgh! You've opened up a can of worms there. I fall into the CISC camp.
Regards,
Rob Philpott.
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Aaaargh!
The 6502 was no RISC CPU! Look at it's register set and addressing mode. Does not really look reduced, right?
Could it be that you mean the CDP1802, which probably really was the first RISC CPU on a single chip. The predecessor, the CDP1801, still was made up of two chips. And by the way, it also was one of the earliest CMOS CPUs.
Both things made it unpopular. CMOS was considered to be slow and RISC (for lack of the proper words) was usually just called 'weird'.
The language is JavaScript. that of Mordor, which I will not utter here
This is Javascript. If you put big wheels and a racing stripe on a golf cart, it's still a f***ing golf cart.
"I don't know, extraterrestrial?"
"You mean like from space?"
"No, from Canada."
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Well, you're right from a theoretical viewpoint. From a practical one, 6502 and other cores such as the Motorola 6805 and big bros were RISC when compared to Z80 and Intel's.
The internal architecture and the BUS was even much simpler than Z80.
Thanks for point it out, though...it's roughly 30 years I don't use them...
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Who told you that? RISC does not really mean that a processor is inferior and only has a spartan instruction set.
A RISC processor usually has a large set of general purpose registers, CISC processors have a small set of registers, each dedicated to a specific purpose. In this respect the 6502 is definitely CISC.
A CISC processor usually has many different address modes and several variants of each instruction to support different combination of source parameter and destination parameter addressing. In this resprct the 6502 again is CISC. A RISC processor does not have all those addressing modes and emulates them over the general purpose registers. The 'reduced instruction set' means only that there are not a hundred variants of each instruction to support all the addressing modes.
The language is JavaScript. that of Mordor, which I will not utter here
This is Javascript. If you put big wheels and a racing stripe on a golf cart, it's still a f***ing golf cart.
"I don't know, extraterrestrial?"
"You mean like from space?"
"No, from Canada."
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Nothing about inferiority: I was just pointing the relative simplicity of the logic of a 6502 than a modern processor. At the time, the 6502 was a myth!
Well, about RISC/CISC definition, looks like you're right: don't want to discuss that.
I did NOT study computer science, I'm an electronic engineer, thus I'm not sure about many definitions and theory behind computers.
I programmed enough 6502, 6805, AVR, but also x86 and a very minimal Z80: all that using assembler. What I remember is the huge diversity in the typical instruction ability, as well as the relative cost for doing something, up to the dramatic hardware (e.g. BUS) difference between CPUs.
Whereas 6502, 6805 (it's a MCU family, just consider the core) were very simple as architecture and hardware, had a small yet "trivial" set of ops even fast, the counterpart Z80, x86 and so were much more complex and powerful. I remember the 386 opcodes book which was huge and terribly complex.
So far:
- 6502, 6805 were a reduced (small and simple) instruction set? Yes: easy to check.
- Z80, x86 were a complex (vast and powerful) instruction set? Yes: easy to check as well.
To close, maybe both the 6502 and the 6805 should be classified as CISC, but I can't see them much different than a RISC. I believe they're borderline.
The "Indirect addressing" section of Wikipedia explains pretty well that:
http://en.wikipedia.org/wiki/MOS_Technology_6502[^]
Thank you anyway for clarify the differences.
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Have you looked at an ARM processor at all? 
And they describe that as "RISC" ! 
Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
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In 1987 I would have bought a Acorn Archimedes, but I never even got to see one. It was the first computer withn an ARM processor. I love RISC. Still, my first computer still has a CDP1802, which was first sold in 1976, 11 years earlier.
The language is JavaScript. that of Mordor, which I will not utter here
This is Javascript. If you put big wheels and a racing stripe on a golf cart, it's still a f***ing golf cart.
"I don't know, extraterrestrial?"
"You mean like from space?"
"No, from Canada."
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Dividing a frequency by 2 is not really hard. Or by any other power of two. Still, it only matters what goes into the CPUs clock input, not what frequency it is derived from.
The language is JavaScript. that of Mordor, which I will not utter here
This is Javascript. If you put big wheels and a racing stripe on a golf cart, it's still a f***ing golf cart.
"I don't know, extraterrestrial?"
"You mean like from space?"
"No, from Canada."
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Why? My little CDP1802 is from 1976 and its maximum clock frequency is at 3.2 MHz. The holy wars back then were about processors and, despite being the enemy, the Z80 (if I remember right, that's the CPU in a ZX-81) was available in versions of up to 4 MHz at that time.
Weak memory, but I think it was the Z80B that went up to 4 MHz.
Edit: The Z80A went up to 4 MHz. The Z80B went up to 6MHz. Just looked it up.
The language is JavaScript. that of Mordor, which I will not utter here
This is Javascript. If you put big wheels and a racing stripe on a golf cart, it's still a f***ing golf cart.
"I don't know, extraterrestrial?"
"You mean like from space?"
"No, from Canada."
modified 2-Mar-15 11:13am.
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And the last version of a Z80 I used (one of the Z180 variants with 1MB address space via built in MMU) was running at 32MHz.
It was a very nice little processor, and I was quite sad to abandon it in favour of the ARM family - but I needed the processing power, and the Z80 was just too slow.
Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
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How many MHz does a piece of wire have?
I wanna be a eunuchs developer! Pass me a bread knife!
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Yes, I had one. Z80 at the time was a much better CPU - faster clock speeds, more registers, easier 16-bit addressing.
"If you don't fail at least 90 percent of the time, you're not aiming high enough."
Alan Kay.
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so, I was approached last week by a start up to be their CIO.
my question is should I take it?
Current position. Large Multi National. They are going thru some pains. IE no bonus this year for the first time in like 20 years, barely any raises. Raises delayed by 4 months, 12% reduction in workforce. My job here seems safe. My boss is pretty awesome and he has alot of respect in the company and I think I have his respect as well. But I am silo'd into this one job doing pretty much one thing leading this diverse team which is fun.
New position, Obviously CIO, would have as staff of perhaps 2, would be bringing in the development and oversight of IT from being outsourced. Small very very small company that just got some amazing financing. Would be able to pick my people, pick my platforms.
So thoughts?
To err is human to really mess up you need a computer
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Quote: I have his respect
I have that in my position and it is as rare as hen's teeth.
Quote: leading this diverse team which is fun
This is also rare. I actually find my job fun and am not planning on giving it up for anything.
Consider carefully what you are giving up before leaping at a new opportunity which may be a fun challenge you will never regret... or a nightmare you regret for the rest of your life. I have done some leaping in my time and have had both outcomes - the nightmare first, obviously.
Factors to consider:
Are you single and carefree? Go for it - you can probably handle anything that comes up.
Are you happily married with children in good schools, mortgage and college fund all organised? - Think really hard about losing all that.
- I would love to change the world, but they won’t give me the source code.
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With small companies amazing growth potential at great risk.
With large company little growth potential at small risk.
It's like trading on the stock exchange, you put your money up and take your chances.
New version: WinHeist Version 2.1.0
My goal in life is to have a psychiatric disorder named after me.
I'm currently unsupervised, I know it freaks me out too but the possibilities are endless.
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In a World of disposables I would go for the cash.
With friendly greetings, 
Eric Goedhart
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Always a tough choice: stick to the large stable company that is shedding jobs or go with the start-up that could run out of money at any moment...
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CIO of ... 2 people ? The title has some glitter, but I would not hop for that particular reason.
How did they approach you ? Personal network, or some fancy agencies giving you a phone call ?
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personal network of people I have worked with in the past recommended me.
I didn't even know what I was meeting with the guy about. Just knew that he was a friend of a friend. It was an interesting meeting.
To err is human to really mess up you need a computer
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What do you think the chances of the start up are? The one startup I worked at, I didn't evaluate what I thought their chances were when I started. I ended up leaving after a couple of years because I realized that there really wasn't a good opportunity for the company.
They were eventually bought by Google, but none of the options ended up being worth much, so I made the right decision to leave.
From that, I'd only work at a startup that I really believe in.
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When you are at that level, you are either on the way up or the way out.
If you are happy in your current job, I would stick with that if in your position; however not everybody makes the same choices I do.
I'm retired. There's a nap for that...
- Harvey
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