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How early 8-bit arcade machines differed in design from 8-bit home computers

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Re: How early 8-bit arcade machines differed in design from 8-bit home computers

#31

Post by tinus_hn »

laumars wrote: post #20
okyougotmenow wrote: post #19

Earlier quoted context omitted.

Arcade cabinets are the wrong comparison. Better are home consoles, in particular the NES/Famicom. A fine-scrollable tilemapped background + hardware sprite multiplexing made it trivial to develop games for the Famicom that would be technological marvels on contemporary home computers, yet no western computer manufacturer came up with that design, despite being small additions on top of text-mode graphics and hardwar…

Some western micro computers did have some of that though. The C64 did have hardware scrolling, which is why you see a higher calibre of scrolling games on that machine than you would on the Amstrad CPC 464 (which did not have hardware scrolling). It all comes down to expense though. You could throw the whole kitchen sink into the computer but then how much would it cost to manufacture and how much would you need to…

The hardware scrolling in the C64 is pretty trivial, it can only shift the screen up to 7 pixels horizontally and vertically and mask the borders a bit. If you want to do scrolling you have to move the memory contents around which costs a lot of cpu time.

On a console you typically have a circular buffer and the screen is a movable window on it, so you only have to paint one row every time.

Re: How early 8-bit arcade machines differed in design from 8-bit home computers

#32

Post by jandrese »

ggambetta wrote: post #29

> And then for the rest of the year spend all my after-school time trying to build rather poor impressions of those arcade games on my home computer, not unlike a cargo-cult worshipper on a post-WWII pacific island trying to build a US military radio station from wooden sticks. Hahaha, this matches my own experience exactly :) Playing the likes of Dragon Ninja / Bad Dudes and then trying to reproduce them on the Spec…

It was a little rare to have an "end" to the games in those days. Generally there wasn't much space for something so extravagant. More often you would overflow a value somewhere and semi-crash the game.

Re: How early 8-bit arcade machines differed in design from 8-bit home computers

#33

Post by callmekit »

ggambetta wrote: post #29

> And then for the rest of the year spend all my after-school time trying to build rather poor impressions of those arcade games on my home computer, not unlike a cargo-cult worshipper on a post-WWII pacific island trying to build a US military radio station from wooden sticks. Hahaha, this matches my own experience exactly :) Playing the likes of Dragon Ninja / Bad Dudes and then trying to reproduce them on the Spec…

What's wrong with the Spectrum's Green Beret? And R-Type Spectrum conversion was very good.

Re: How early 8-bit arcade machines differed in design from 8-bit home computers

#35

Post by jacobush »

callmekit wrote: post #33
ggambetta wrote: post #29

> And then for the rest of the year spend all my after-school time trying to build rather poor impressions of those arcade games on my home computer, not unlike a cargo-cult worshipper on a post-WWII pacific island trying to build a US military radio station from wooden sticks. Hahaha, this matches my own experience exactly :) Playing the likes of Dragon Ninja / Bad Dudes and then trying to reproduce them on the Spec…

What's wrong with the Spectrum's Green Beret? And R-Type Spectrum conversion was very good.

It didn't magically make the Spectrum have more colors or better sound, like the arcade game had.

Re: How early 8-bit arcade machines differed in design from 8-bit home computers

#36

Post by jacobush »

tinus_hn wrote: post #31
laumars wrote: post #20

Earlier quoted context omitted.

Some western micro computers did have some of that though. The C64 did have hardware scrolling, which is why you see a higher calibre of scrolling games on that machine than you would on the Amstrad CPC 464 (which did not have hardware scrolling). It all comes down to expense though. You could throw the whole kitchen sink into the computer but then how much would it cost to manufacture and how much would you need to…

The hardware scrolling in the C64 is pretty trivial, it can only shift the screen up to 7 pixels horizontally and vertically and mask the borders a bit. If you want to do scrolling you have to move the memory contents around which costs a lot of cpu time. On a console you typically have a circular buffer and the screen is a movable window on it, so you only have to paint one row every time.

Still, it wasn't like you had to push all the pixels. You only moved 8x8 (or whatever it was) characters. So the C64 was pretty decent, actually. Also, of course you had to shift characters once every 8 pixels.

I was envious as hell on my MSX, which had no pixel shifting at all.

Re: How early 8-bit arcade machines differed in design from 8-bit home computers

#37

Post by barbecue_sauce »

jlv2 wrote: post #34

And a direct link to his WebAssembly version of the emulator: https://floooh.github.io/tiny8bit/bombjack.html Took longer to boot then I expected, but after that played quickly.

Second stage music of Bombjack is clearly a rendition of Lady Madonna by The Beatles.

Re: How early 8-bit arcade machines differed in design from 8-bit home computers

#38

Post by cmrdporcupine »

tinus_hn wrote: post #31
laumars wrote: post #20

Earlier quoted context omitted.

Some western micro computers did have some of that though. The C64 did have hardware scrolling, which is why you see a higher calibre of scrolling games on that machine than you would on the Amstrad CPC 464 (which did not have hardware scrolling). It all comes down to expense though. You could throw the whole kitchen sink into the computer but then how much would it cost to manufacture and how much would you need to…

The hardware scrolling in the C64 is pretty trivial, it can only shift the screen up to 7 pixels horizontally and vertically and mask the borders a bit. If you want to do scrolling you have to move the memory contents around which costs a lot of cpu time. On a console you typically have a circular buffer and the screen is a movable window on it, so you only have to paint one row every time.

Atari 8-bit could fine scroll horizontal and vertical. In 1979.

https://www.atarimagazines.com/compute/issue67/338_1_Atari_F...

Re: How early 8-bit arcade machines differed in design from 8-bit home computers

#39

Post by gumby »

> The entire remaining space on the mainboard is dedicated to the video decoding hardware (besides a couple of RAM and ROM chips).

This wonderful post points out a fascinating cultural shift that I've never seen written up but is visible in the traces of various papers.

Although there was a Cambrian explosion of computer designs in the 1960s and 1970s they did follow a common evolutionary path, to whit: there really was a central processing unit, and around it fed various peripheral parts, primarily memory, I/O (channel controllers) and the like.

A lot of the vocabulary and assumptions of minicomputers and microprocessors came from this world, though the big difference in the late 60s was letting the CPU do some of the I/O (and one of the weird things about C, fundamentally a minicomputer language, was that it didn't have IO keywords or commands).

So when the Alto was designed one of the biggest weird things about it was not the bitmapped display itself but its support: the bus speed was only 3/2 the screen refresh rate! That blew people away (in fact if you wanted to do a lot of computation you'd end up blacking out most of the screen for a while).

==

The games developers went the other way: they started with hardcoded logic and only later were able to use MPUs. so to them they'd just accelerate part of the design with the computer. You can even see this as the domains started to merge; the early Atari computers like the 400 and 800 weren't only what we'd call today game consoles but had built-in sprite hardware that you could call from your programs.

Re: How early 8-bit arcade machines differed in design from 8-bit home computers

#40

Post by mikepavone »

axilmar wrote: post #3

I will forever wonder why 8-bit computers of the 80s didn't have more powerful video hardware. It's not that the technology wasn't available, since most arcade machines at the time had a lot more powerful graphics hardware than 8-bit home machines. (I will also forever wonder why Sega's 16-bit console didn't have hardware sprite scaling and rotation, since that was the main attraction of Sega games at the time...) I…

> (I will also forever wonder why Sega's 16-bit console didn't have hardware sprite scaling and rotation, since that was the main attraction of Sega games at the time...)

An interview with one of the hardware designers on the Mega Drive/Genesis VDP suggests they wanted this, but that didn't have enough die space. It's also not clear how comparable to their arcade hardware this would have actually been even if it was present. Scaling and rotation requires non-sequential access to the source data which the VRAM used in the MD/Gen is not very good at. My guess is that the limitations would have been similar to what you saw with the scaling hardware on the Sega/Mega CD (i.e. relatively low frame rate due to the limited bandwidth available for updating VRAM).

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