Some people have blamed me that I used rather wrong information about the 6502:6800 performance ratio. I have to try and justify myself. There are several links which refer to official MOS claims
http://www.cpu-collection.de/?l0=co&l1=MOS
https://archive.archaeology.org/1107/fe ... p_cpu.html
I have also found out a very interesting the 6800 and 6502 comparison
https://archive.org/details/byte-magazi ... 7/mode/2up
where several code samples clearly show that the 6502 is 2 times faster than the 6800. And I have claimed that the 6502 only up to 2 times faster.
Indeed, it would be really interesting to get EDN magazines from 1975 but it seems very difficult. I can only hope that one day those precious magazines will become available on the net. We can only know that there were AH Systems benchmarks for the 8080, 6800 and 6502...
I was thinking about several different kinds of data processing and I always got that the 6502 should be about 2 times faster. Maybe we need to open a special thread "6502 vs 6800"? IMHO we should use real algorithms for applications. Reentrant or not self-modifying code has used rather rarely, only for interrupt handlers and ROM respectively...
Sorry my post is a large one and the next will follow.
More concerning, calling the 6800 a mediocre processor is useless without some actual data to back it up.
Thank you very much again for your highly interesting comments.
I used words "rather mediocre" which give me some room for maneuvers.
And BTW I have checked a dictionary and found out the next definition
The roots of the adjective mediocre are from the Latin medial, "middle," and ocris, "mountain." If you think about it, the middle of a mountain is neither up nor down and neither here nor there — just somewhere in between. The definition of mediocre is "of ordinary quality," "merely adequate," and "average.
It is nothing offensive in this word, it means just satisfactory, almost quite well, but not outstanding or bad.
Case in point, the TMS9900 16 bit processor in the TI 99/4A is hardly a "mediocre" processor. But, the performance of the TI 99/4A suffered greatly due to system design constraints that strangled the poor processor's capabilities.
Sorry I haven't understood your point. Would you like to clarify it? You can check my material about the TMS9900, I have never used word "mediocre" there -
https://litwr.livejournal.com/1575.html - however I mentioned several weak points of this processor.
The 6502 crowd can write some sample apps (sorting app or sieve or something else) and the 6800 crowd on the SWTPC or the MC10 could be asked to write the same thing. Results could then be compared. If you take out IO and such, the comparison would be pretty valid.
I can repeat, it sounds interesting for me. However, the MC10 uses the 6801 which is much more powerful that the 6800. There were no popular computers based on the 6800.
The 6800 will be better at handling tabular data greater than 1 page, given the 16 bit index register, while the 6502 will do better on loops and smaller tables due to the 2 index registers.
I can't agree. IMHO the 6502 is much better with processing of any tabular data. Let us make a simple routine which makes a simple checksum by XOR-ing of 1024 bytes.
Code: Select all
ldy #0
ldx #4
lda #hi(tab)
sta loop+2
tya
loop eor loop,y
iny
bne loop
inc loop+2
dex
bne loop
align 256
tab .byte <data> ;1000 bytes are here
I am sure that the analogous 6800 routine will be 2-4 times slower.
we know he got seed money from MOS/CSG to stand up WDC.
It sounds unusual for me because CSG never used the CMOS 6502.
It was not made because CSG was cheap, and would have had to retool to add those instructions into their layouts, which they had no reason to do so.
IMHO this also means that for CSG the 65C02 new instructions had little importance. However you are rather right, Commodore almost didn't spend any money on technology improvement.
Saying Bill did not improve the NMOS 6502 seems highly editorial to me. He improved it by moving it to CMOS.
This is exactly what I wrote about...
While the information on the C128 is not wrong, it suggests it's the CPU's fault. The problem with the C128 was not the CPU, but the fact that there was little demand for such a 65XX unit, and most developers could drive more margins by targeting the 64, which the C128 could also emulate.
Please could you explain why is it possible to think that I wrote about the CPU's fault? I wrote about an unfriendly environment around the 6502 systems at 2 MHz in the USA until the second half of the 80s.
I also don't see how the code for the 65C02 would turn out to be "more cumbersome..."
We discussed one my example earlier on this forum but let me repeat. I uses a 256-byte table with 128 jump vectors. Those vectors must have odd addresses. On the NMOS 6502 I pack such a table in a single page but on the CMOS 6502 I get a one byte ugly displacement.
The only reference I have on the arkanoid bug is around the NES version of Arkanoid
Sorry I meant Asteroid game for an Atari computer. Bill told about it -
https://www.youtube.com/watch?v=7YoolSA ... be&t=28230
It is strange I could not google this information and I am sure that it was written somewhere on the net. Internet really has viruses which are eating valuable information.
Many people know that Bill has a 32 bit version of the '02 designed, which was called Terbium. The market never asked for it, so he never produced it. The author seems to be under the delusion that companies will just create optimized versions of their designs when no one has asked for them, using personal cash to fund an effort which may never get used. Bill puts designs into production when people come with cash to buy them, not before. Same with Zilog and Intel. If we want to blame someone, blame the market, not Bill. I am sure he wanted to do the 32 bit '02, because he wrote the design up. But, a suitable customer never materialized.
It is very interesting but it proves my point that Bill couldn't replace a company. He is a genuine engineer but he needed also a marketing specialists who could provide sells and get more customers. Some assistance from other engineers could help too.
I'll admit it's tough to slog through the article with the heavy editorial bias. If the author wants people to read the article, I think it'd be best to put the facts first in the main body of the article, and then put the editorialization at the end.
Maybe word bias is not right for this case? I really don't have a special personal opinion about the 6502 or other processors. In a sense I like them all but I also like to examine them carefully and find their drawbacks. Maybe the main problem is my English because in Russian my material has about 7 times greater popularity.
I still not understand your point about my phrase "the 6502 was only microscopically improved and made artificially partially incompatible with itself" in relation to the 4510. This phrase relates to the 65C02 only. Information about the 4510 follows much later.
Um, bugs can indeed be documented and still be bugs. All the CPUs I use have a long list of errata on them and people do indeed consider them bugs. Documenting something does not absolve it of guilt.
It is a very slippy ground. IMHO if we have a documented specification and its later changes then we have rather concept changing than a bug...
Currently, the article still says "...he never tried to improve this processor himself." It's just wrong. Fagin improved the 8080 by designing the Z80. The same is true of Bill.
My phrase states "It has turned out that Bill worked on the 6502, with only specifications received, and he never tried to improve this processor himself". Maybe it is something wrong with my English but I want to say exactly the same things you have claimed that Bill Mensch just followed the market, he made things only in response to the market demands. Maybe I should use phrase "he never took the initiative to improve this processor"?
IMHO Faggin created rather a completely new processor which has compatibility with the 8080. He designed its ISA, implemented a technological process to make the Z80, he also participated marketing of the Z80. Bill Mensch got the 6502's ISA ready from Chuck. He had a great role in the NMOS 6502 implementation and he was the only designer of the CMOS 6502. He made the great work in field of electronics but the ISA design and marketing were not his fields.
Bill said good words that the NMOS 6502 changed the world but the CMOS 6502 were produced in larger volumes. IMHO the existence of this forum and the presence of us here is due to the NMOS 6502, the CMOS 6502 just exploited the success of its very successful variant.
CSG had faster 6502s, but making the interleaved dual processor design forced all parts to be twice as fast as normal, and CBM was not about to pay for sub 100nS DRAM to move the C128 to 3 or 4MHz (which demanded 6 or 8MHz capable DRAM), and they definitely could not switch from an interleaved memory design, as the 64 mode forced constraints. Commodore was cheap. It had nothing do with keeping the CPU speed down. It had to do with cost. And, I'm not sure what you mean about the poor C128 design. Bil Herd would challenge that notion a lot
. I'm not a huge fan of the 128, but I don't see any glaring design issues. The Z80 looks shoehorned in because it was. Marketing demanded the unit be CP/M compatible, thinking the 64 mode could run the old C64 CP/M cart, but that cart was never robust, didn't work on newer 64s, and Bil got so frustrated trying to make it work he ended up just pushing the design into the C128 to check off the requirement. If there's a design issue, it'd be there.
Bil Herd and Commodore got a great commercial success with the C128, so I hope our theoretical discussion can't harm anyone. I don't understand why you write about 3-4 MHz. They didn't even actually provide 2 MHz. Indeed they provided 2 MHz for the 6502 but rather theoretically, I wrote about this. IMHO Commodore just heavily and rude exploited people expectations about an upgraded C64 instead of making a real upgrade. They just gave the C64 with better but slower Basic and a bunch of incompatible modes which require special hardware to get benefits from them. The Z80 at the actual 1.6 MHz looked rather very poorly in 1985.
He's a pretty smart fellow, you should go chat with him.
If he reads this thread I must express my great and sincere respect to him here. I also hope that he will tell us more about the 6502 history details someday.
Yeah, I saw you made that comment before. But, I looked at the ad, and I don't see any hint of 16 bits for a CPU. Can you point out where you see it? "The first of a low cost high performance microprocessor family" cannot be it, as that could mean so many other things.
It has phrase
Thus, MOS Technology has left holes in the 650X instruction bit pattern to accommodate a "quasi-16-bit machine."
Now, if you want to argue the CPU should have required a 48 pin DIP carrier and brought out the 16 bits of the data bus directly, and had an internal 16 bit ALU, there's probably more weight to that argument.
The 16-bit data bus is a quite right idea for me but I don't understand your words about 16-bit ALU. Doesn't the 65816 have 16-bit ALU?! It is shocking for me.
one thing that is more important than features alone, especially in the 1970s and 1980s, was getting the price right (as in low) with just enough features so that it sells.
Thank you very much for your remarks and an interesting link. IMHO prices are very difficult matter for correct conclusions. The Apple II was always rather an expensive computer. The Apple Mac was also not among the cheap computers... There is always market for very expensive designs.
look up the dates for the 68000 and the 8086 and then look at when the first 16/32 bit computers were first sold
Sorry I missed the idea. IMHO the computers used the mentioned processor appeared almost immediately, like the KIM-1 for the 6502.
At the same time, most of the computers that these chips (6502, Z80) are being used in, are undergoing cost reduction measures by the manufacturers so that the older model of computers can stay price competitive. Not a good market for a new more expensive eight bit microprocessor...
IMHO the history showed that people are always happy to get better hardware which implies better software. However this somehow missed 8-bit computers. 16/32-bit designs like the IBM PC or Apple Macintosh were always evolving. 8-bit designs could have been more evolving too. It is strange for me that Apple stopped the Apple III, Commodore made a strange C128, the BBC Micro was too expensive, etc.
If the 6502 and Z80 were used only as low power controllers we haven't discussed them now. There are a lot of controllers, they works but they don't have history.
Acorn did design and manufacturer an export version for sale in the U.S.A. As far as I know, they were not blocked or locked out as such.
Maybe I missed something but how could they design and manufacturer an export version for sale in the U.S.A without some market researches? So they had some information that they could sell their computers their. IMHO it could be education. The BBC Micro was more advanced than the Apple II in many ways and the price of the Apple II could be even higher than for the BBC Micro. So it was rather a block or lock around computers for educational purpose in the USA. I know that some people tried to start selling the Amigas there but it was impossible. Compare capability of the Amiga and Apple II...