brain wrote:
In your original post, you asked for any comments around use of English. As a native English speaker, I can assure you "mediocre" is not viewed to an English reader as "satisfactory". [...] Thus, the English reader will see:
"The 6800 is a mediocre processor"
as
"The 6800 had the potential to be a better or more capable processor, but failed to live up to that expectation and is just average."
Thank you very much for your help with my English. However "satisfactory" and "mediocre" have a common synonym "average". Indeed there are too many subtleties which are not easy for a non-native speaker. Anyway your last phrase shows the meaning which is close to my idea about the 6800. It was surpassed by the 6502, 6801, 8085, Z80, 6809, ... Indeed I know that the 6800 was a quite popular controller but my article is about processors for computers and from this point of view the 6800 was rather mediocre. I repeat I use words "rather mediocre" (= supposedly mediocre) not just "mediocre".
brain wrote:
You didn't quote enough of my response. I said:
Quote:
But, calling something "mediocre" is just asking for the fight. 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.
I'm not comparing the TMS9900, I'm suggesting that the use of the word will put the reader on the defensive, as most TMS9900 enthusiasts are when people claim that processor is "mediocre", when in fact it's due more to the constraints imposed by the TI 99/4A design (and that's a statement TI 99 4/A folks will argue). In short, my point is that "mediocre" is a word best used if you want to dismiss or belittle something and you can't say the item has no value or that it is less than average.
It is definitely not my case because I have written about the 6800 without connection to any system. Yes, indeed, my text about the rather mediocre 6800 has some collateral effect of belittling of the 6800 but I just follow the trend based on MOS Technology ads. They wrote that the 6501 and 6502 were much cheaper, much faster, much less in size, etc.
brain wrote:
brain wrote:
Saying Bill did not improve the NMOS 6502 seems highly editorial to me. He improved it by moving it to CMOS.
Quote:
This is exactly what I wrote about...
We shall agree to disagree then. I think saying a designer of a chip did not improve the chip when everyone knows he designed the much improved successor to the IC means he improved the chip.
I have written
Quote:
While Intel, Motorola and others had already made 16-bit processors of new generations, the 6502 was only microscopically improved and made artificially partially incompatible with itself. Even if you compare the improvements made in the Motorola 6801 over the 6800 or the Intel 8085 over the 8080, they are gigantic compared to those made in the 65C02, and Intel and Motorola made them much earlier.
This means the comparison of amount of work done by WDC and other microprocessor producers. I want to emphasize that in 1975 the 6502 was one of the best but in 1983 the 65C02 was far behind the leaders. If we compare job done for the development of the 6502 and for the x86 (the 8086 is source code compatible with the 8080) we can say that the job done for the 6502 was rather very tiny.
brain wrote:
The statement implies that the 2MHz mode (which you belittle a bit in your sentence by noting it could only be used in one of the modes, which is not completely true, you could run the 64 mode in 2MHz without the VIC-II running, which some 64 apps used to speed up code running during VBLANK on the C128 in 64 mode) was a joke because noone targeted the "mode", but the sentence implies the "mode" is "the 2MHz mode". But, that's misleading. No one targeted the C128 mode because the unit would run perfectly fine in 64 mode, and targeting that mode gave the software developer/seller a 20 Million customer base as opposed to a 4.5Million potential customer base. It had nothing to do with the speed of the CPU, but (again), the issues with the PC the 2MHz operation was contained within
You are right that it is possible to limitedly use 2 MHz mode inside the main 1 MHz mode but it is rather marginal programmings for experts so it is rather excusably to omit such a peculiar detail. You know the Commodore Plus/4 PAL can use 2.2 MHz clock but there are only less than 5 demos which use that mode.
I completely disagree with your logic about the C128 software. New software for better hardware arrives quite soon. Let us remember the IBM PC compatibles... The 2 Mhz mode was just abandoned because it was almost completely incompatible with the c64 and the whole idea behind of the C128 was this compatibility. Anyway I don't try to explain why the 2 MHz was deserted I just show the fact of its desertion, people just were not given a real opportunity to use it. The most crazy thing for me is 64 KB VRAM in the C128DCR while MMU were still limited to 128 KB only. They added RAM for a deserted chip but left the main CPU without additional RAM feed! IMHO Commodore just buried itself with such crazy designs.
brain wrote:
Quote:
Sorry I meant Asteroid game for an Atari computer. Bill told about it -
https://www.youtube.com/watch?v=7YoolSA ... be&t=28230It 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.
I'll have to look that up.
Bill said quite definitly about this case...
brain wrote:
I think you're being too harsh on Bill in the article, but it's your prerogative to do so, so I have no further comment.
Maybe it is because I would like to have better processors in computers but Bill just gave the 6502 more lifespan in a controller role. I don't want to be harsh to any person. IMHO it is a story about the 6502 is rather harsh.
brain wrote:
Well, that's why I continue to respond to the thread. I gather you're interested in mastering the English language, and what better way than to write about technical subjects you already know about.
Thank you very much.
brain wrote:
Quote:
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.
My point was that the statement doesn't have a time frame attached to it. You can read it as having an implicit "By the mid 1980's" prepended to the paragraph in which the "microscopically improved" sentence exists, but I read it as being more a comment for all time. In other words, I read it as:
Quote:
the 6502 design was never materially improved and the minimal improvement made in the CPU line created partially incompatible devices.
But my phrase is
Quote:
While Intel, Motorola and others had already made 16-bit processors of new generations, the 6502 was only microscopically improved and made artificially partially incompatible with itself.
So we have a time frame when Intel and Motorola made their 16-bit processors... Maybe I missed something?
brain wrote:
I think everyone agrees if was a bug, or at least an unplanned use case, so it was documented as opposed to fixing (they fixed the ROR bug).
Even the official WDC documentation doesn't directly claim this a bug.
BTW in his latest interview Bill Mensch said that the case with the ROR instruction was not a bug.
brain wrote:
I don't agree that the Fagin 8080->Z80 ISA differs from Mensch 6502 -> 65C02 ISA. I don't think Fagin designed the Z80 ISA, but rather took the ready made ISA from the 8080 and extended it, just like Bill extended the 6502 ISA. (The fact that Fagin also designed the 8080 ISA is not relevant here).
As I said before, I think he improved the processor by moving it to CMOS and cleaning up the illegal opcodes. Our disagreement may stem from my feeling that faster speed and movement to CMOS gave the 6502 line a longevity that it would never have achieved in the NMOS variant, thus I value that significantly, and I think you do not. You appear to give more weight to additional opcodes and functions on-chip, like multiply and divide instructions and such. I don't think either is wrong per se, but if Bill had added a ton of new opcodes but had not moved it to CMOS, it would never have hit the speeds we now see, and it would never have been popular in the embedded designs (all of them needed a CMOS design to lay into their SOC designs). This forum would have suffered as a result.
The Z80 has about 500 new instructions in addition to the original 8080 instructions. It has a lot of new registers. It has two completely new ways to work with interrupts. It has built-in DRAM regeneration support. It uses only 5 Volt PS. ... I dare to recommend you to read
https://litwr.livejournal.com/1195.html for more details. IMHO if we compare volume of changes for the Z80 after the 8080 and for the CMOS 6502 after the NMOS we get that the former is at least 10 fold greater than the latter.
You are wrong saying that CMOS automatically gives higher speed. CMOS technology allowed to make faster chips than NMOS only in the early 90s when the CMOS 65816 and Z80 at 16 MHz started to be manufactured. You can also check the speed of the CMOS RCA 1802.
brain wrote:
The 3-4 MHz refers to the actual bus speed of the system. In dual memory access designs, in which two devices share a common memory by time slicing access to the memory (of which the VIC-20, 64, 128, and others were in this camp), the bus speed has to run at twice the CPU speed. So, in the 1MHz 64, the memory has to run at 2MHz, and in the C128, the memory has to run at 4MHz. My point was that DRAM speeds of the day, coupled with the dual memory access designs used in these machines, limited CPU speed.
We have 4 Mhz RAM in the C128 it was not a problem in 1985. It is very strange for me that they refused to make the SID and VIC which could have worked at 2 Mhz, they did them only for the unlucky C65.
brain wrote:
I don't think he's on here, but he's been wildly successful in spite of his lack of improving the 6502.
Indeed but my article is not about success in business but about successes of processors.
brain wrote:
Quote:
Thus, MOS Technology has left holes in the 650X instruction bit pattern to accommodate a "quasi-16-bit machine."
I will note my eyes are not what they used to be, but I just pored over the ad, and I can't see any statement like that in the ad.
I mentioned a document which can be get from
viewtopic.php?f=1&t=6184#p76752 - seek for the second word "quasi".
BillG wrote:
Trust me, the signed arithmetic example is not contrived. I am working on compilers and that is a very possible case in a language permitting mixed variable sizes and signedness.
There were no compilers for 8-bit systems which supported 8-bit signed values until the 90s. I know only Express Pascal for the 8080 which can handle all Turbo Pascal integer types. Express Pascal appeared only in 1990. So your examples around signed arithmetic are very contrived for me. ROM Basics use rather FP-math...
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