Commodore 64 BASIC and KERNAL on Atari 8-bit hardware

https://github.com/unbibium/atari64

by TMWNN • 5 years ago

92 38 5 years ago

github.com

TMWNN• 5 years ago

Source: https://www.reddit.com/r/c64/comments/p24fo8/i_modified_the_...

intricatedetail• 5 years ago

I remember Atari basic was quite superior, so probably that's why there was no port. Awesome work!

tenebrisalietum2• 5 years ago

Didn't it do something weird with strings where you had to periodically LIST and reload your program to prevent crashes?

jhallenworld3• 5 years ago

Yeah, famous bugs. Atari BASIC source is fully documented in this book:

https://archive.org/details/ataribooks-the-atari-basic-sourc...

See appendix B, memmove() was broken.

ataylor284_2• 5 years ago

It's unfortunate that Commodore shipped BASIC 2.0 on the 64. They already had shipped PETs with the much superior BASIC 4.0 years earlier. It was likely a cost saving measure: they had a more favorable licensing deal with MS on BASIC 2.0 and it fit on fewer ROM chips. Too late the C128 came with BASIC 7.0 which was actually quite good (for an 8-bit BASIC anyway).

timbit423• 5 years ago

It is quite good but it is also quite slow compared to BBC BASIC on the 2 MHz 6502-based BBC Micro.

rasz2• 5 years ago

Jack Tramiel was the OG of cutthroat business practices. He bought Basic for a flat fee from Gates in 1977, that included rights to modify and ship on any hardware platform he wanted.

Doing business with Gates was decent, Tramiel said. "He came to see me, tried to sell me Basic, and he told me that I don't have to give him any money, all I had to give him was $3 per unit. I told him I was already married," Tramiel said.
Tramiel instead told Gates he'd pay a flat fee of $25,000, rejecting the idea of paying $3 for each Commodore 64 sold. "In about six weeks [Gates] came and took that $25,000. Since then he did not speak to me," Tramiel said.

https://www.computerworld.com/article/2813900/innovators-rem...

vardump• 5 years ago

It's unfortunate that Commodore shipped BASIC 2.0 on the 64.

It might also have contributed to the success of C64 by "encouraging" early use of machine language. BASIC is great, but to truly make C64 shine you do need assembly language.

Notably, it was also pretty trivial to expand BASIC capabilities. A lot of utilities did just that, like adding graphics commands and sprite extensions. Simons' BASIC is probably the most comprehensive example, and it also came as a cartridge.

thought_alarm• 5 years ago

It's unfortunate that Commodore shipped BASIC 2.0 on the 64

There are many things that are unfortunate about the way the C64 was shipped. For Commodore, the entire point of the C64 was to slap it together and shove it out the door as quickly and cheaply as possible, to try and capitalize on the unexpected success of the VIC-20, which was itself slapped together when the VIC graphics chip didn't sell.

What's fascinating about the C64 is just how right that "slap it together and shove it out the door" strategy was.

Market price and timing were absolutely key to the C64's early success. All those bugs and missing features? The 3rd party developers would quickly take care of that.

The products that Commodore tried to make good, better than "shove it out the door" quality, like the Plus/4 and C128, were complete duds. Much better design, much better software, and irrelevant.

ecpottinger• 5 years ago

If I remember right, Atari Basic had 4 byte floats and Commodore Basic has 4 byte floats. The extra precision mattered for some programs, but the small size made the Atari Basic faster.

jhallenworld3• 5 years ago

Atari had 6 byte floats, BCD. Commodore had 5 bytes, binary.

tenebrisalietum2• 5 years ago

CBM had 5 byte floats I think you meant--edit: maybe it was 6. 5 byte mantissa and 1 byte exponent??

CBM BASIC was a Microsoft product and I think more or less what all the Microsoft BASICs did was convert everything to floats internally--even when not really needed. For example the index in a FOR I=1 to 10 was dealt with internally (and slowly) as a float--including the operation to increment it by 1 or the STEP value.

If Atari BASIC didn't do that it would have made things faster in many situations. Apple's Integer BASIC was faster because it didn't support floats at all, if you could deal with the almost C-style strings IIRC.

jhallenworld3• 5 years ago

I always thought it would be cool if the line numbers were floating point. You could always insert a line between any existing ones then.

bonzini2• 5 years ago

Integer variables were written I%. I%=I%+1 was certainly faster than I=I+1, but I am not sure if that extended to FOR loops.

ataylor284_2• 5 years ago

CBM had 5 byte floats, but when they were copied into the floating point "registers", they were expanded into a 6 or 7 byte representation for speed. It was 8 bits of exponent, 1 bit sign, and 31 bits of mantissa (with one extra implicit bit since the leading bit is always 1).

It's true there was very little performance gain to using BASIC integer variables, since they'd be converted to floats internally almost always. The one real advantage of integers is that a DIMed array of ints was more compact than an array of floats.

megameter• 5 years ago

Atari BASIC used 48-bit BCD floats and the routines were not well optimized, making it one of the slowest at the time(later retrohobbyists have made various patches as well as faster BASIC implementations). It was also Microsoft-incompatible which made it an odd duck among the microcomputer BASICs.

rbanffy3• 5 years ago

but the small size made the Atari Basic faster.

The 6502 running at 2MHz also helped a lot.

hulitu• 5 years ago

Imagine a 6502 at 3.4 GHz.

mypalmike• 5 years ago

Atari BASIC's tokenization scheme should have made it faster than others. But it suffered from some poor implementation details which made it perform quite poorly.

https://en.wikipedia.org/wiki/Atari_BASIC#Performance

sys_64738• 5 years ago

Blasphemy.

classichasclass4• 5 years ago

Username checks out. :)

yitchelle• 5 years ago

Talking about retro technology, I am shamelessly plugging my twitter account for retro tech adverts.

https://twitter.com/OldTechAdverts

I've been posting those amazing old tech adverts out of magazines 90s, 80s and older. Looking at adverts for retro games, retro electronics and others. Hope to see you there.

bwship• 5 years ago

Old school gaming is just so great. Jelly Boy just got released on the Switch for Super Nintendo Online. I seriously can't believe that up until like 3 days ago, I had no idea this game existed. My get woken up every morning now by my 4 year old to play it. We go around the house saying JELLY BOYYYY, and fist punching through our t-shirts to make it look like the game. Just so fun to have those little flashes of when games where just quirky and fun.

Commodore 64 BASIC and KERNAL on Atari 8-bit hardware

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