Atari Vs C64 --- 80s Computer scene etc chat...

[TMR]

Send to the post, please

 

Load that into anything that lets you see the palette and it'll have the C64 colours in the first sixteen (i dumped it using CCS64's 16 colour screenshot mode and Pepto palette) and the rest as black.

footy.bmp

[TMR]

I dont think so. for example a 16 bit addition takes up more instructions on the 6510 as than on the z80. while you can manipulate 16bits as one with the z80 you have to broke it down to 8 bits on 6510, which is a very big disadvantage. not to speak about the more registers AND two register sets. z80 is a much better cpu than the 6510.

 

i started playing with Z80 about a month ago, the way it accesses memory was... well okay i know there's bias because i've been coding 6502 for so long, but it feels very long winded, almost like trying to do everything with indirect indexed addressing.

[emkay]

I'm really pissed to repeat it in every forum we meet: The A8 is not the C64 and vice versa.

 

oh, thanks for clearing me up

 

Why do I have doubts about a learning effect of yours? Probably because the C64 does enough "FX"

[Thomas Jentzsch]

Well, those are only reduced Photos. Just for showing what it means to have 16 colours fully available for an image.

Uhm, I know that more colors help. What did you think?

 

And those pictures have 1000+ colors (probably taken from a 18 bit palette), not just 16 from a 7 bit palette

[Oswald]

The main advantage of the Z80 is the memory saving by using shorter command orders.

 

nope. the main advantage is that you can implement algorithms more efficiently due to more and/or wider registers, you can add 16 bit wide numbers inside the cpu, better stack, more sophisticated instruction set etc etc etc.

 

add hl,de

 

 

to do the same thing on 6510 you do:

 

 

lda $10

clc

adc $20

sta $20

 

lda $11

adc $21

sta $21

 

a "bit" less efficient isnt it ?

Edited April 26, 2008 by Oswald

[emkay]

Well, those are only reduced Photos. Just for showing what it means to have 16 colours fully available for an image.

Uhm, I know that more colors help. What did you think?

 

And those pictures have 1000+ colors (probably taken from a 18 bit palette), not just 16 from a 7 bit palette

 

The pictures have 16 colours out of a "real colour" palette.

[emkay]

nope. the main advantage is that you can implement algorithms more efficiently due to more and/or wider registers, you can add 16 bit wide numbers inside the cpu, better stack, more sophisticated instruction set etc etc etc.

 

add hl,de

 

 

to do the same thing on 6510 you do:

 

 

lda $10

clc

adc $20

sta $20

 

lda $11

adc $21

sta $21

 

a "bit" less efficient isnt it ?

 

 

The main advantage of the Z80 is the memory saving by using shorter command orders.

 

What is wrong with that sentence, in your opinion?

Edited April 26, 2008 by emkay

[Oswald]

I dont think so. for example a 16 bit addition takes up more instructions on the 6510 as than on the z80. while you can manipulate 16bits as one with the z80 you have to broke it down to 8 bits on 6510, which is a very big disadvantage. not to speak about the more registers AND two register sets. z80 is a much better cpu than the 6510.

 

i started playing with Z80 about a month ago, the way it accesses memory was... well okay i know there's bias because i've been coding 6502 for so long, but it feels very long winded, almost like trying to do everything with indirect indexed addressing.

 

 

6502 is very primitive, in fact chuck peddle said they never intended it to be used in computers, but in intelligent electronic devices like printers, point of sales, etc. if you look at 680000's or the x86's they all do it in the same style z80 does: the idea being: memory is slow, manipulate data inside the cpu registers.

[Oswald]

The main advantage of the Z80 is the memory saving by using shorter command orders.

 

What is wrong with that sentence, in your opinion?

 

that the real advantage is speed and not memory saving.

[Oswald]

The pictures have 16 colours out of a "real colour" palette.

 

yeah, poor c64 colors are out of an unreal color palette

[Allas]

Well, the balloon c64 image is 255 colors indexed, so is a interlaced screen.

 

no its not, its just emulating the PAL circuitry's color mixing and TV's blur.

 

Maybe, we can refine the Atari image with interlaced mode to show more shades and better resolution.

 

yeah welcome to flicker hell, which doesnt shows in this faked picture.

 

 

Ok, but it's better to manage the exactly pixel pictures. First, because I appreciate how C64 do, second because I have a NTSC C128 and I don't see any PAL enhanced stuff here. The Atari interlaced picture from Atari have some flickering, but I don't take care because I work fast. However it can be do it on interlaced without flickering. Do you remember the theory about non-flickering colors on interlaced modes?

[Thomas Jentzsch]

The pictures have 16 colours out of a "real colour" palette.

The red one, yes. The yellow one has 1995 colors.

 

Anyway, those pictures show, that it's not only the number of colors, but also the size and quality of the palette which counts.

[emkay]

The pictures have 16 colours out of a "real colour" palette.

The red one, yes. The yellow one has 1995 colors.

 

 

Autsch....

You really should click on the image and load the full image, not the shrinked preview

 

Anyway, those pictures show, that it's not only the number of colors, but also the size and quality of the palette which counts.

 

correct.

[frogstar_robot]

Fact is that I know how to obtain the features I talked about. If I'd have the time, my task would be to write a doc about '"how to make full use of Pokey's features".

 

If it is your intent to convince others then you'll need to come across with examples. Nobody has to believe anything. Since you are the one making positive assertions then demonstrate them. You said bare examples of the effects can be realized in BASIC? Then post them!

[Thomas Jentzsch]

Autsch....

You really should click on the image and load the full image, not the shrinked preview

 

Anyway, those pictures show, that it's not only the number of colors, but also the size and quality of the palette which counts.

 

correct.

Fine, we both agree. How would you evaluate the quality of the Atari palette?

[emkay]

The pictures have 16 colours out of a "real colour" palette.

 

yeah, poor c64 colors are out of an unreal color palette

 

After seeing all of your posted pictures, it seems to be the best description.

[Bryan]

Atari and Commodore like folded in the mid 1990s probably because the Windows based PC has been increasing in strength and everyone wanted one. Like I said Atari and Commodore never tried to conform to a standard and did not make their rarely systems backward compatible. What if the ST were directly backward compatible with the XL/XE systems and able to run the old stuff? Yes, the ST and Amiga lines kept to a standard into their later models.

 

The biggest problem with most 80's computers were:

 

1. The platforms were not designed with expansion in mind and so they'd be discarded and replaced with a new architecture every few years. Although the PC was lame and slow, it was very modular and expandable. Of course, what really drove it into the mainstream was that it was also based on off-the-shelf chips which made it easy to copy.

 

2. None of these companies saw what the future potential for their machines were. They were sold as expensive toys rather than the basis for future products. No company was willing to give up any control over their platform to improve their share of the market. Even Apple nearly disappeared with their mis-handling of the Mac (especially the Mac II's - the computer for the rest of us? $8000? Really?)

 

In the end, the PC won because everyone else retreated to their niche and pretended it wasn't there.

 

-Bry

[Oswald]

The pictures have 16 colours out of a "real colour" palette.

 

yeah, poor c64 colors are out of an unreal color palette

 

After seeing all of your posted pictures, it seems to be the best description.

 

which brings us back to the speccy level: "my colors are nicer than yours"

 

well farewell I had enough of this bullshit for this year

[Gury]

atari inc. effectively collapsed because of the c64, tramiel bought it for some bargain price and saved later. if thats not a success then nothing is. also the a8bit line effectively died out in the second half of 80s because it lost it to the c64. it couldnt be beaten more than that

Oswald, you are wrong. A8 line of computers didn't die until late 1990, when Atari ended last production of XE line of Atari computers, because it was forced to. XL/XE series did very well in Europe, especially in Germany and Poland. Here in Slovenia mostly C64s and Spectrums were spreaded, but also many XL/XE users existed which I knew. I saw what C64 is capable of, but it didn't impress so much, so I stayed with trusty Atari 130XE and it will fortunatelly never change. I and my friends had great time playing all the Atari games from the 80'.

[thomasholzer]

you dont need to be a musician to make a non detuned music. (atleast thats how it works on the c64) you have the exact formula that what value is what musical tone and thats about it....

 

That's why the SID is a real Synthesizer chip and POKEY is not.

 

I'm really pissed to repeat it in every forum we meet: The A8 is not the C64 and vice versa. So, many solutions have to be solved in a fully different way.

For having good music on the SID, just use the synth... On the A8 you have to do some software routines for it.

Similar to this, you have to produce a 2x2 or 4x4 mode in software, while on the A8 you simply can use one.

Where SID is using his envelop capabilities, ANTIC can store graphics data to give the CPU some more time for doing other things.

 

Well, I saw some C64 demos saying "it is not how it is done. It is what you get".

 

But this rule seems only allowed for the C64 , Oswald?

 

 

The pictures have 16 colours out of a "real colour" palette.

 

yeah, poor c64 colors are out of an unreal color palette

 

After seeing all of your posted pictures, it seems to be the best description.

 

which brings us back to the speccy level: "my colors are nicer than yours"

 

lucky for us then, because it was always Speccy vs C64, and we all know the result, don't we.

[Bryan]

Pokey can in fact do anything SID can do and something more, be it that SID envelope generator and pitch resolution is of course far superior, and only the analog filters (which in fact lie outside the SID chip for a big part) are not there. ADSR could be emulated. At 50 up to 200 Hz, tunes get crystalclear.

 

There's squarewave, pulsewave, triangle, sawtooth, a vast continuum of polycounter distortions when choosing the right combinations of pokey's channelsand clockings. There's a ring-mod alike effect, there is a sync-like effect. The 16bit filter gives also very nice surprises, which are also possible on SID though, but not with a minimum of used CPU power. On pokey they're all for free, though it's far out of the book.

Examples?

 

Here's some stuff I did on Pokey in the hopes of writing a more accurate Pac-Man clone someday. The first is the Pac-Man main theme using the triangle trick. The 2nd is the death sound using the arbitrary duty-cycle trick and the triangle trick. Both are running on 60Hz VBI with no digi-stuff.

 

-Bry

 

(pacdie.mp3 plays the original arcade followed by Pokey)

Pokeytune.mp3

pacdie.mp3

Edited April 26, 2008 by Bryan

[emkay]

Fine, we both agree. How would you evaluate the quality of the Atari palette?

 

Is hard to say. But to have the chance of using 8 different shades of one colour in hires seems to be not that bad.

Actually, simple fading FX are not possible on the C64. Also you cannot build colour correct shadows on it.

 

The ATARI palette is somehow a good B/W image generator & the colours are very good for comic style graphics without getting eye cancer.

[emkay]

well farewell I had enough of this bullshit for this year

 

I don't believe you can live without bullshit.

But, If you'll do us this favor.

 

Fare well, lebe wohl, a viszontlátásra ...

[Bryan]

Biggest problem with the C-64.

 

It's stuck with that "porthole" of a screen. People that forked out for one of their monitors must have felt a bit ripped off.

 

That was done so they could use a specific pixel clock. It's faster than the Atari's which means it's a little more compressed horizontally.

 

Vertically, the Atari lets you pick any height you want in the DL.

[Bryan]

Fine, we both agree. How would you evaluate the quality of the Atari palette?

 

Is hard to say. But to have the chance of using 8 different shades of one colour in hires seems to be not that bad.

Actually, simple fading FX are not possible on the C64. Also you cannot build colour correct shadows on it.

 

The Atari palette is built on a range of luminances, but only one color modulation level. This means dark colors will be very saturated and may display "color shadows" (dark areas) on the horizontal intersection of two colors. Bright colors will be somewhat washed out which is why there's no good red. It requires a much stronger color signal.

 

This can be fixed by using the luminance as the gain for the chroma. As a color gets brighter, its color modulation should get stronger too. I've built a few test circuits to do this and it gives more of an RGB style look to the output.

 

The 1200XL contained a crude circuit to attempt to boost saturation, but it caused more problems than it solved. It would have been better if GTIA had used that unused low bit in the palette as a saturation boost.

 

-Bry

Edited April 26, 2008 by Bryan