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History of MOS 6502 [video]

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Re: History of MOS 6502 [video]

#11

Post by vidarh »

PythonicAlpha wrote: post #4
PhantomGremlin wrote: post #3

Not a bad talk, considering that the guy wasn't even alive when the original 6502 was designed. He was confused on a few minor points, some of which Wikipedia clears up.[1][2] a) There were really two chips done, the 6501 and 6502. The difference was in a few pins, the 6501 was fully pin-compatible with the 6800, the 6502 was easier to use in a system design since it did not require a two-phase non-overlapping 5V rai…

I did not watch the talk yet, but there was also a third model (maybe later): The 6510 -- it was fully software compatible, but had 6 integrated I/O pins that could make small computer designs easier. Commodore used it for the C64 computer, because the 6 I/O pins saved for extra I/O chips. The 6 I/O pins would also be faster than external circuits because they could be accessed via the zero-page (address 0 and 1, as…

There were several other models. Some of the Amiga models have a 6502 compatible SoC with an embedded PROM and small bit of RAM on chip for example.

(Then of course there's the Western Design Centre 6502 descendants, which include 16-bit extensions etc.)

Re: History of MOS 6502 [video]

#13

Post by kjs3 »

Theodores wrote: post #7

There are some cringeworthy aspects to this talk if you know the story. That does not actually distract because it is interesting watching someone tell the story when they revere the 6502 yet have not coded for it. At the time that the 6502 hit the computer scene in a mass-market way it wasn't like you coded your code straight into a computer. Instead you actually wrote code out on paper. Then you looked up the opcod…

This is completely wrong, and it's obvious the author is the one who is "cringeworthy". I most certainly "coded your code straight into a computer" back in those days. The Commodore PET and Apple 6502 computers had built in BASIC, in ROM, and assembler environments were easy to find if you had a floppy. The Apple at least had any number of other languages like Pascal and Forth. And the idea that the 68000 was easier if you knew 6502 is laughable.

Re: History of MOS 6502 [video]

#14

Post by rasz_pl »

Theodores wrote: post #7

There are some cringeworthy aspects to this talk if you know the story. That does not actually distract because it is interesting watching someone tell the story when they revere the 6502 yet have not coded for it. At the time that the 6502 hit the computer scene in a mass-market way it wasn't like you coded your code straight into a computer. Instead you actually wrote code out on paper. Then you looked up the opcod…

>At the time that the 6502 hit the computer scene in a mass->market way it wasn't like you coded your code straight into >a computer. Instead you actually wrote code out on paper. >Then you looked up the opcodes and typed them into a >margin. That was what you typed in on many personal >computers of the time.

That still sounds easy, real men input code with switches, into 6809 in this example : https://www.youtube.com/watch?v=IXu8P2qGoj8

Re: History of MOS 6502 [video]

#15

Post by rasz_pl »

PhantomGremlin wrote: post #6
PhantomGremlin wrote: post #3

Not a bad talk, considering that the guy wasn't even alive when the original 6502 was designed. He was confused on a few minor points, some of which Wikipedia clears up.[1][2] a) There were really two chips done, the 6501 and 6502. The difference was in a few pins, the 6501 was fully pin-compatible with the 6800, the 6502 was easier to use in a system design since it did not require a two-phase non-overlapping 5V rai…

I forgot to mention another thing he didn't know was useful d) BCD instructions, which he thinks are "kind of silly", and perhaps they are now that computers run at many GHz. But they were very useful in the old days. E.g. CBASIC [1] implemented BCD floating point math. Here's what Wiki says about it: CBASIC proved very popular because it incorporated 14-digit binary-coded decimal (BCD) math which eliminated MBASIC's…

Incidentally BCD is one of the "perks" you get with Intel in mobile/embedded. When Intel says "x86 compatibility" they dont mean reusing pre compiled binaries, what they really mean is 30 year old legacy cruft like BCD, or 64 bit processors booting in real mode.

Re: History of MOS 6502 [video]

#16

Post by Zardoz84 »

kjs3 wrote: post #13
Theodores wrote: post #7

There are some cringeworthy aspects to this talk if you know the story. That does not actually distract because it is interesting watching someone tell the story when they revere the 6502 yet have not coded for it. At the time that the 6502 hit the computer scene in a mass-market way it wasn't like you coded your code straight into a computer. Instead you actually wrote code out on paper. Then you looked up the opcod…

This is completely wrong, and it's obvious the author is the one who is "cringeworthy". I most certainly "coded your code straight into a computer" back in those days. The Commodore PET and Apple 6502 computers had built in BASIC, in ROM, and assembler environments were easy to find if you had a floppy. The Apple at least had any number of other languages like Pascal and Forth. And the idea that the 68000 was easier…

Apple I and ][ Had a machine code monitor on ROM, and on some version had a mini-assembler. Search for Woz's monitor (and take a looks to the assembly code, it's very interesting)

But I agree that Theodores's post there is something wrong. Only Sinclair's ZX81/82 abuse of the Z80 to generate the screen. Zx Spectrum's had an ULA chip that handles the screen generation and other stuff, like the cassette interface.

Re: History of MOS 6502 [video]

#17

Post by Zardoz84 »

vidarh wrote: post #11
PythonicAlpha wrote: post #4

Earlier quoted context omitted.

I did not watch the talk yet, but there was also a third model (maybe later): The 6510 -- it was fully software compatible, but had 6 integrated I/O pins that could make small computer designs easier. Commodore used it for the C64 computer, because the 6 I/O pins saved for extra I/O chips. The 6 I/O pins would also be faster than external circuits because they could be accessed via the zero-page (address 0 and 1, as…

There were several other models. Some of the Amiga models have a 6502 compatible SoC with an embedded PROM and small bit of RAM on chip for example. (Then of course there's the Western Design Centre 6502 descendants, which include 16-bit extensions etc.)

Wut ? Amiga's runs over 680X0 cpus.

Re: History of MOS 6502 [video]

#18

Post by boomlinde »

Zardoz84 wrote: post #17
vidarh wrote: post #11

Earlier quoted context omitted.

There were several other models. Some of the Amiga models have a 6502 compatible SoC with an embedded PROM and small bit of RAM on chip for example. (Then of course there's the Western Design Centre 6502 descendants, which include 16-bit extensions etc.)

Wut ? Amiga's runs over 680X0 cpus.

I believe the 6502 was used as part of a keyboard controller in at least some Amiga models.

Re: History of MOS 6502 [video]

#19

Post by jonjacky »

kjs3 wrote: post #13
Theodores wrote: post #7

There are some cringeworthy aspects to this talk if you know the story. That does not actually distract because it is interesting watching someone tell the story when they revere the 6502 yet have not coded for it. At the time that the 6502 hit the computer scene in a mass-market way it wasn't like you coded your code straight into a computer. Instead you actually wrote code out on paper. Then you looked up the opcod…

This is completely wrong, and it's obvious the author is the one who is "cringeworthy". I most certainly "coded your code straight into a computer" back in those days. The Commodore PET and Apple 6502 computers had built in BASIC, in ROM, and assembler environments were easy to find if you had a floppy. The Apple at least had any number of other languages like Pascal and Forth. And the idea that the 68000 was easier…

No, he's right. The PET and Apple were second generation 6502 machines - intended to be personal computers. The first 6502 products were evaluation kits like the KIM-1, which only had a keypad and seven segment LEDs for entering and viewing code in hex. Even this was quite an advance over the previous generation like the Altair where you had to enter code by flipping switches. This page has a picture, explains the process and shows some handwritten source code:

http://blog.jgc.org/2013/04/how-i-coded-in-1985.html

(Despite the title, this was more typical of 1976 or so.) It seems awkward, but it was quite workable for embedded controllers, which was the original application that the microprocessor manufacturers had in mind.

Re: History of MOS 6502 [video]

#20

Post by Theodores »

kjs3 wrote: post #13
Theodores wrote: post #7

There are some cringeworthy aspects to this talk if you know the story. That does not actually distract because it is interesting watching someone tell the story when they revere the 6502 yet have not coded for it. At the time that the 6502 hit the computer scene in a mass-market way it wasn't like you coded your code straight into a computer. Instead you actually wrote code out on paper. Then you looked up the opcod…

This is completely wrong, and it's obvious the author is the one who is "cringeworthy". I most certainly "coded your code straight into a computer" back in those days. The Commodore PET and Apple 6502 computers had built in BASIC, in ROM, and assembler environments were easy to find if you had a floppy. The Apple at least had any number of other languages like Pascal and Forth. And the idea that the 68000 was easier…

Commodore PET and Apple machines were for people who had rich daddies and lived in America. For those of us in the Rest of The World getting access to a computer was not as simple as that. We had to wait for things like the VIC-20 to come along, the PET was unseen outside of a magazine cover. There was no sea of surplus computers, particularly ones with floppy disks. Pen and paper was how things got done. You, not knowing that, shows how little you know.

True, you could program in almost any language you wanted on almost any platform. However Forth was a novelty and of the few people I knew that had Pascal, none of them actually used it - the box sat there, on the shelf. Much like today you could choose to program in Forth if you really wanted to (or Cobol) but you didn't, simple as. The 'killer apps' of the time - games - were generally written in assembler as in assembler you could do things not possible with one of your 'other languages'.

As for your quip about 68000 not being easier if you knew 6502, do you just arrogantly dismiss everything out of hand? No evidence given?

Shortly after the hey-day of things being done in assembler, I was the only person in a very large university class to get 100% for some 68000 based assembly assignment. This was my first go at 68000 and I completed my work in less than one hour. Sure 'introductory 68000' might be easy, complete 'hello world' stuff for a genius like you, however none of the hundred or so that were on that course could churn out the assignment like I could, straight off the bat. They struggled for weeks on it and most of the class cribbed answers from each other, they were that bad. The difference I had was solid 6502 experience, I took to 68000 like a duck to water, everyone else was still struggling to get their heads around what to me was a simple task.

Sure my reminiscences from aeons ago are totally anecdotal but I went on to do lots of stuff in 68000 and, without that first bit of 6502 experience, I would have struggled.

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