Great article! It actually makes an interesting point about the Z80 interrupt system: the Z80 does have an extremely powerful interrupt mode IM2 which supports an interrupt vector table with up to 128 entry points anywhere in memory and (theoretically) any number of prioritized interrupt sources, but this capability was not properly supported in western home computers (at least as far as I'm aware from the Speccy, CPC and MSX), in East German home computers (Z1013, Z9001, KC85/2..4) this mode was fully supported - which is interesting because those designs were much inferior to western home computers (at least when it comes to features required for video games).
The reason is that IM2 requires interrupt sources to implement a fairly complex 'daisy chain protocol'. Support chips are supposed to place the low byte of a 16-bit interrupt vector address on the data bus when the Z80 starts handling an interrupt, the Z80 will read that byte, and combine it with the special I register as high byte to build a 16-bit address which points into the interrupt vector table. Next the Z80 will read the 16-bit value from that address - which is the entry point of the interrupt service routine - and jump there.
Interrupt priorities are hardwired via the above mentioned 'daisy chain', and this prioritization is what makes the interrupt support logic complicated because pending interrupt requests should not get lost while a higher priority interrupt is serviced (it's all described here in detail: http://www.z80.info/1653.htm).
The standard Z80 family chips (CTC, PIO, SIO) all supported this complex protocol, but not any of the custom chips in western home computers. East German home computers used TTL logic and Z80 family chips instead of custom chips and thus could make full use of the Z80 interrupt capabilties, while western designs typically didn't (I would have taken sprites and hardware-scrolling any day over powerful IM2 interrupts though).
Thought I'd point out that this system has a really good MiSTerFPGA core that supports the Neo Geo AES, MVS and CD systems [0] if you'd like to give it a go and software emulators aren't your thing. MiSTerFPGA, for those unaware, is a project that uses a Terasic DE10 Nano FPGA evaluation board to reproduce older consoles, computers, and arcade systems in hardware [1]. And as a heads up, the cost for entry into MiSTerFPGA will soon drop sharply as there are clone boards for the DE10 and expansion memory boards that will cost well under half of current offerings. At under $99 for the DE10 clone and $20 for the 128K SRAM memory expansion that is basically a must have [2], you'll be able to run consoles up to PS1 / Saturn / N64 level. Above that you'll have to go to software emulation or hang on to see what the next round of FPGA-based retro-consoles (Replay2, MarsFPGA) will be able to offer.
> Genuine question, but would you notice the difference playing a game running a good software emulator or a FPGA hardware emulation?
If you are playing on a CRT, definitely. FPGA hardware emulation is sufficiently accurate that those with CRTs can use lightguns and have them work as expected.
I personally am not wild about latency issues, I didn't expect to really feel a difference between a good emulator and the MiSTer when I built one a few years ago, I was just bored and looking for a new toy which I could justify as a development tool to learn FPGAs if it didn't work out.
The first game I played on it, Sonic 2, I was shocked how much I could immediately feel the difference compared the RetroPi instance I normally played on.
It does depend on the game and platform though, I can't tell the difference when playing Super Mario All-Stars for example, but SMB1 is night and day.
In general the more "to the metal" the platform was, the more critical clock-accurate emulation of every component is to correct software operation, the more the FPGA helps. Modern platforms with buffers everywhere are less tightly coupled. I don't understand, for example, the desire for Dreamcast FPGA emulation. Once we got to the point of framebuffered 3D and PCM audio being the standard, when consoles started to gain operating systems, IMO the cost/benefit analysis just doesn't play out. Those platforms are usually quite friendly to efficient high-level emulation and don't require the level of low-level clock-for-clock perfection that a "racing the beam" era platform does.
It is worth noting that there is no inherent reason a FPGA hardware emulation would be more accurate than a software emulation, it's just that FPGAs make synchronizing the emulated components at a cycle-accurate level so much easier than it is in software. Doing it in software usually requires a lot of CPU cycles which means you need a beast of a machine to run it at full speed (see all the articles early in bsnes' existence about how it needed a top end PC of the time just to play in real-time) but if you have the cycles available it can be done.
Latency is another matter, a software emulator running on a normal mainstream PC operating system has a lot of layers between it and the hardware that a FPGA doesn't, so the FPGA will always win there. In theory when using native inputs and analog outputs latency is exactly identical to the real thing.
Not Neo Geo, but I was fascinated with Galaga a while ago and alternated between using MAME on Linux and MiSTer, and it definitely felt better on MiSTer. No stutters in frame rate, felt slightly more responsive, probably a little less latency on the audio. Didn't make a huge difference given my lousy playing, but it was interesting to compare them back to back.
Also, although the above is probably not the best case scenario comparison on the software side (MAME on an underpowered laptop), having written an emulator myself (not necessarily a great one), and particularly going through a convenient portability layer like SDL, there's just a lot of code between you and the hardware, which itself isn't representative of what you're emulating - for instance, sound and video are running at different clock rates and will drift apart, whereas on real hardware there's a single oscillator driving everything, so you have to jump through hoops to adapt the sound to the video rate, and latency creeps in.
One thing I didn't see mentioned is that there's a function for automatic sprite animation loops based on a global timer. This is how some Neo Geo games have huge environmental background animations like waterfalls, pulsing/flickering lights, etc. without bogging down the CPU.
Years ago, a computer magazine (I think in the UK) did an amusing look into the flip lids of the current CD consoles. Playstation, Saturn, Jaguar (I think) and the Neo Geo.
They placed a penny on the closed lid, and pressed the button to open it.
I forget which moved the penny furthest, but the Neo Geo came last.
If it doesn’t come with a cartridge costing several hundred (1980s) pounds, it’s just not a Neo Geo. No wonder it had no patience for flipping mere pennies.
I have two western models (the original mechanical tray was not released in the west), and have not had any issue. The gen 2 is one of the best looking systems ever made, imho. It’s built like a tank and the materials feel premium.
Angry Video Game Nerd, on Youtube, had a huge issue finding a working one and I don't think he ever did. He just kept ordering new ones and kept getting duds. Even took it to his friend that performs unusual repairs and the guy said they were all 100% broken. I believe you, though. Might have just been a problem with the resale market being flooded with all the broken ones.
AFAIK, Rolfe's persona started with him including two added videos at the end of some horror DVD he made in Art School. One for Castlevania 2 and another.
However, I'd argue that Mike Matei provided all the serious production value of the show. Which is ironic, because fans of the show grew to hate him both for his lower production value experimental vids starring him on the channel and eventually for controversial cartoons made when he was like 18. So while they were clamoring for Rolfe to ditch Matei, the irony was that the show starred by Rolfe was like 98% reliant on Matei's professional talent. Just my take.
Also, I don't think he was ever intended to represent a modern gamer. If you were our age, you'd understand that Rolfe's gimmick was to dredge up the era whereby garbage games were being produced with Nintendo Power magazine giving them high reviews, leaving us horribly disappointed every Christmas and Birthday when we got the games we asked for. Has less to do with gaming than just an era in which we were ripped off constantly. Without social media, we would blame ourselves and his gimmick is relatable and cathartic in a sense.
Fond memories… a game shop had one you could play on as a guest, there was always a queue. Unimaginable to young me that some people actually owned them.
I remember playing and enjoying a side scrolling shooter with weird penis-shaped space ships (Last Resort).
OK, so you know how every time you boot up a Neo-Geo game you see that little piece of technobabble:
MAX 330 MEGA
PRO-GEAR SPEC
It took me years to figure this out, but it actually means something. (Hell, even "Blast Processing" means something; it was some marketroid's sizzle term for the very fast DMA controller the Genesis had). Anyways, to break it down, MAX 330 MEGA means that cartridges could have a maximum size of 330 megabits. Bank switching would later increase this limit, with appropriate sizzle text on game boot. PRO-GEAR SPEC means that the technical specs of the home console are identical to the Neo-Geo arcade machines which are considered professional equipment or "pro gear". The Neo-Geo console was an arcade board in a console case -- at time of release one of the more advanced arcade boards at that. And the cartridges weren't home ports -- they were literally the arcade games. So of course the Neo-Geo was going to be vastly more expensive than the SNES or Genesis -- it had more memory and more advanced hardware than either of them, its games had vastly more ROM, and chips were pricey in 1990.
Thanks for the info. I also just translated it and 330 megabits is around 40 megabytes, so no wonder the cartridges were eye-wateringly expensive back in the late eighties/early nineties.
Cartridges didn't actually get that big for years though. When actual cartridge size started surpassing 100 megabits (12.5 MB) in 1992 or so, an additional screen reading "The 100 Mega Shock!" would appear.
Even at 100 megabits or less, the Neo-Geo cartridges were still huge. SNES cartridges started out at 4 megabits.
I was always in awe of the graphics and was always envious of those who had one (only one boy at my school ever claimed to own one, but we never had any proof) but when I finally had the chance to play the games (via NeoRageX, amazing piece of software, written in assembly I believe) I was kinda disappointed. To begin with I was never a fan of fighting games (SFII being the one exception) and all the games I played were very arcade-y (because well, they were literal arcade games). No NeoGeo game could’ve given me the gaming experience of, say, A Link to the Past for the SNES, I think.
Not only NeoGeo games — I would say that there is no game that could give me the experience of A Link to the Past for the SNES. Best game ever (for me).
Pulstar and Blazing Star were very good. And Super Sidekick 2-3.
Most emulators had switches for arcade settings in order to maximize the game time per match.
Turns out the sheer amount of hardware in the Neo Geo and cartridges does kinda explain the price of everything around it! (Too bad about the game library...)
I love „Neo Turf Masters“ — which always has been Neo Geo exclusive AFAIK and possibly the best golf simulation if you don’t actually play Golf. There is a Switch „port“ which really is just emulating the console but a fun diversion from Zelda and Mario.
I remember being obsessed with this system, too. It was more like a legend than a system. Everyone knew someone that knows someone with a Neo Geo. It was never within my reach to play one. A $600 system with $200 games in the 90s? But they were all arcade-level and only the richest kid (or kid whose parents were competing after a messy divorce) had one.
I am kicking myself now for not buying one in Tokyo in 2009 when I saw one for (after exchange rate) 200 USD. They are selling in the same shops now for ~1000.
If this article sparks your interest, a good first game to try out is one from the Metal Slug series. I don't know any other that is so beautifully drawn and animated, like a cartoon come alive.
I love the Metal Slug series, they are the only arcade games that I can actually complete in a real arcade xD
Crazy story, one time at Taito Hey (highly recommended retro arcade in Akihabara) I saw a dude completing Metal Slug X with two characters at once, one which each hand, with zero deaths o_O
Great article! It actually makes an interesting point about the Z80 interrupt system: the Z80 does have an extremely powerful interrupt mode IM2 which supports an interrupt vector table with up to 128 entry points anywhere in memory and (theoretically) any number of prioritized interrupt sources, but this capability was not properly supported in western home computers (at least as far as I'm aware from the Speccy, CPC and MSX), in East German home computers (Z1013, Z9001, KC85/2..4) this mode was fully supported - which is interesting because those designs were much inferior to western home computers (at least when it comes to features required for video games).
The reason is that IM2 requires interrupt sources to implement a fairly complex 'daisy chain protocol'. Support chips are supposed to place the low byte of a 16-bit interrupt vector address on the data bus when the Z80 starts handling an interrupt, the Z80 will read that byte, and combine it with the special I register as high byte to build a 16-bit address which points into the interrupt vector table. Next the Z80 will read the 16-bit value from that address - which is the entry point of the interrupt service routine - and jump there.
Interrupt priorities are hardwired via the above mentioned 'daisy chain', and this prioritization is what makes the interrupt support logic complicated because pending interrupt requests should not get lost while a higher priority interrupt is serviced (it's all described here in detail: http://www.z80.info/1653.htm).
The standard Z80 family chips (CTC, PIO, SIO) all supported this complex protocol, but not any of the custom chips in western home computers. East German home computers used TTL logic and Z80 family chips instead of custom chips and thus could make full use of the Z80 interrupt capabilties, while western designs typically didn't (I would have taken sprites and hardware-scrolling any day over powerful IM2 interrupts though).
Thought I'd point out that this system has a really good MiSTerFPGA core that supports the Neo Geo AES, MVS and CD systems [0] if you'd like to give it a go and software emulators aren't your thing. MiSTerFPGA, for those unaware, is a project that uses a Terasic DE10 Nano FPGA evaluation board to reproduce older consoles, computers, and arcade systems in hardware [1]. And as a heads up, the cost for entry into MiSTerFPGA will soon drop sharply as there are clone boards for the DE10 and expansion memory boards that will cost well under half of current offerings. At under $99 for the DE10 clone and $20 for the 128K SRAM memory expansion that is basically a must have [2], you'll be able to run consoles up to PS1 / Saturn / N64 level. Above that you'll have to go to software emulation or hang on to see what the next round of FPGA-based retro-consoles (Replay2, MarsFPGA) will be able to offer.
[0] https://www.youtube.com/watch?v=Eog8solD9dc
[1] https://github.com/MiSTer-devel/Wiki_MiSTer/wiki
[2] https://x.com/TakiUdon_/status/1801578381613613111
Genuine question, but would you notice the difference playing a game running a good software emulator or a FPGA hardware emulation?
> Genuine question, but would you notice the difference playing a game running a good software emulator or a FPGA hardware emulation?
If you are playing on a CRT, definitely. FPGA hardware emulation is sufficiently accurate that those with CRTs can use lightguns and have them work as expected.
I personally am not wild about latency issues, I didn't expect to really feel a difference between a good emulator and the MiSTer when I built one a few years ago, I was just bored and looking for a new toy which I could justify as a development tool to learn FPGAs if it didn't work out.
The first game I played on it, Sonic 2, I was shocked how much I could immediately feel the difference compared the RetroPi instance I normally played on.
It does depend on the game and platform though, I can't tell the difference when playing Super Mario All-Stars for example, but SMB1 is night and day.
In general the more "to the metal" the platform was, the more critical clock-accurate emulation of every component is to correct software operation, the more the FPGA helps. Modern platforms with buffers everywhere are less tightly coupled. I don't understand, for example, the desire for Dreamcast FPGA emulation. Once we got to the point of framebuffered 3D and PCM audio being the standard, when consoles started to gain operating systems, IMO the cost/benefit analysis just doesn't play out. Those platforms are usually quite friendly to efficient high-level emulation and don't require the level of low-level clock-for-clock perfection that a "racing the beam" era platform does.
It is worth noting that there is no inherent reason a FPGA hardware emulation would be more accurate than a software emulation, it's just that FPGAs make synchronizing the emulated components at a cycle-accurate level so much easier than it is in software. Doing it in software usually requires a lot of CPU cycles which means you need a beast of a machine to run it at full speed (see all the articles early in bsnes' existence about how it needed a top end PC of the time just to play in real-time) but if you have the cycles available it can be done.
Latency is another matter, a software emulator running on a normal mainstream PC operating system has a lot of layers between it and the hardware that a FPGA doesn't, so the FPGA will always win there. In theory when using native inputs and analog outputs latency is exactly identical to the real thing.
Not Neo Geo, but I was fascinated with Galaga a while ago and alternated between using MAME on Linux and MiSTer, and it definitely felt better on MiSTer. No stutters in frame rate, felt slightly more responsive, probably a little less latency on the audio. Didn't make a huge difference given my lousy playing, but it was interesting to compare them back to back.
Also, although the above is probably not the best case scenario comparison on the software side (MAME on an underpowered laptop), having written an emulator myself (not necessarily a great one), and particularly going through a convenient portability layer like SDL, there's just a lot of code between you and the hardware, which itself isn't representative of what you're emulating - for instance, sound and video are running at different clock rates and will drift apart, whereas on real hardware there's a single oscillator driving everything, so you have to jump through hoops to adapt the sound to the video rate, and latency creeps in.
Depends on your own sensitivity to latency and slowdown accuracy. A lot of casual players won't notice, but conversely a lot of enthusiasts will.
Nobody cares about your mister. Why are you people so compelled to tell everyone about them constantly?
https://hard-drive.net/hd/video-games/spend-80-snes-classic-...
One thing I didn't see mentioned is that there's a function for automatic sprite animation loops based on a global timer. This is how some Neo Geo games have huge environmental background animations like waterfalls, pulsing/flickering lights, etc. without bogging down the CPU.
Garou, Metal Slug...
Years ago, a computer magazine (I think in the UK) did an amusing look into the flip lids of the current CD consoles. Playstation, Saturn, Jaguar (I think) and the Neo Geo.
They placed a penny on the closed lid, and pressed the button to open it.
I forget which moved the penny furthest, but the Neo Geo came last.
If it doesn’t come with a cartridge costing several hundred (1980s) pounds, it’s just not a Neo Geo. No wonder it had no patience for flipping mere pennies.
I'm pretty sure Neo Geo CD on the resale market is known for having like a 99.5% defect rate on youtube.
I have two western models (the original mechanical tray was not released in the west), and have not had any issue. The gen 2 is one of the best looking systems ever made, imho. It’s built like a tank and the materials feel premium.
Angry Video Game Nerd, on Youtube, had a huge issue finding a working one and I don't think he ever did. He just kept ordering new ones and kept getting duds. Even took it to his friend that performs unusual repairs and the guy said they were all 100% broken. I believe you, though. Might have just been a problem with the resale market being flooded with all the broken ones.
There’s an optical drive emulator now, no need for discs.
FYI AVGN is not a gaming nerd irl or even interested in games in general. Afaik Mike Matei created and curated AVGN persona. Perhaps even worse James Rolfe doesnt even write his own movie reviews https://www.plagiarismtoday.com/2021/10/05/the-cinemassacre-... https://knowyourmeme.com/memes/events/cinemassacre-plagiaris...
AFAIK, Rolfe's persona started with him including two added videos at the end of some horror DVD he made in Art School. One for Castlevania 2 and another.
However, I'd argue that Mike Matei provided all the serious production value of the show. Which is ironic, because fans of the show grew to hate him both for his lower production value experimental vids starring him on the channel and eventually for controversial cartoons made when he was like 18. So while they were clamoring for Rolfe to ditch Matei, the irony was that the show starred by Rolfe was like 98% reliant on Matei's professional talent. Just my take.
Also, I don't think he was ever intended to represent a modern gamer. If you were our age, you'd understand that Rolfe's gimmick was to dredge up the era whereby garbage games were being produced with Nintendo Power magazine giving them high reviews, leaving us horribly disappointed every Christmas and Birthday when we got the games we asked for. Has less to do with gaming than just an era in which we were ripped off constantly. Without social media, we would blame ourselves and his gimmick is relatable and cathartic in a sense.
Just last week google CTF featured a reverse engineering challenge of a neo geo game!
https://capturetheflag.withgoogle.com/challenges/rev-arcade
Also, the neo geo development wiki is an absolute goldmine of technical information about the console.
https://wiki.neogeodev.org
Fond memories… a game shop had one you could play on as a guest, there was always a queue. Unimaginable to young me that some people actually owned them.
I remember playing and enjoying a side scrolling shooter with weird penis-shaped space ships (Last Resort).
It's too bad that these consoles with their amazing graphics were so expensive at the time.
OK, so you know how every time you boot up a Neo-Geo game you see that little piece of technobabble:
It took me years to figure this out, but it actually means something. (Hell, even "Blast Processing" means something; it was some marketroid's sizzle term for the very fast DMA controller the Genesis had). Anyways, to break it down, MAX 330 MEGA means that cartridges could have a maximum size of 330 megabits. Bank switching would later increase this limit, with appropriate sizzle text on game boot. PRO-GEAR SPEC means that the technical specs of the home console are identical to the Neo-Geo arcade machines which are considered professional equipment or "pro gear". The Neo-Geo console was an arcade board in a console case -- at time of release one of the more advanced arcade boards at that. And the cartridges weren't home ports -- they were literally the arcade games. So of course the Neo-Geo was going to be vastly more expensive than the SNES or Genesis -- it had more memory and more advanced hardware than either of them, its games had vastly more ROM, and chips were pricey in 1990.Thanks for the info. I also just translated it and 330 megabits is around 40 megabytes, so no wonder the cartridges were eye-wateringly expensive back in the late eighties/early nineties.
Cartridges didn't actually get that big for years though. When actual cartridge size started surpassing 100 megabits (12.5 MB) in 1992 or so, an additional screen reading "The 100 Mega Shock!" would appear.
Even at 100 megabits or less, the Neo-Geo cartridges were still huge. SNES cartridges started out at 4 megabits.
I was always in awe of the graphics and was always envious of those who had one (only one boy at my school ever claimed to own one, but we never had any proof) but when I finally had the chance to play the games (via NeoRageX, amazing piece of software, written in assembly I believe) I was kinda disappointed. To begin with I was never a fan of fighting games (SFII being the one exception) and all the games I played were very arcade-y (because well, they were literal arcade games). No NeoGeo game could’ve given me the gaming experience of, say, A Link to the Past for the SNES, I think.
Still an amazing piece of hardware.
> No NeoGeo game […]
Not only NeoGeo games — I would say that there is no game that could give me the experience of A Link to the Past for the SNES. Best game ever (for me).
Pulstar and Blazing Star were very good. And Super Sidekick 2-3. Most emulators had switches for arcade settings in order to maximize the game time per match.
Turns out the sheer amount of hardware in the Neo Geo and cartridges does kinda explain the price of everything around it! (Too bad about the game library...)
By 1998 everyone emulated them at home among SNES and MD with Neorage or Zsnes/Dgen/Gens. Also, by 1997-1998 the PS killed arcades forever.
The reason these consoles were so expensive was precisely because of the cost of hardware required to produce those amazing graphics.
What else would it be?
I love „Neo Turf Masters“ — which always has been Neo Geo exclusive AFAIK and possibly the best golf simulation if you don’t actually play Golf. There is a Switch „port“ which really is just emulating the console but a fun diversion from Zelda and Mario.
https://www.twitch.tv/videos/1211920539
Feels baller as fuck to own an AES, not gonna lie. The system we all lied about owning in middle school!
Love these articles so much and I just love learning about all these systems that obsessed me as a child.
>all these systems that obsessed me as a child.
I remember being obsessed with this system, too. It was more like a legend than a system. Everyone knew someone that knows someone with a Neo Geo. It was never within my reach to play one. A $600 system with $200 games in the 90s? But they were all arcade-level and only the richest kid (or kid whose parents were competing after a messy divorce) had one.
I am kicking myself now for not buying one in Tokyo in 2009 when I saw one for (after exchange rate) 200 USD. They are selling in the same shops now for ~1000.
Very well written.
If you have any nostalgia for (or just interest in) old consoles / arcade machines / game system, this article is well worth your time.
If this article sparks your interest, a good first game to try out is one from the Metal Slug series. I don't know any other that is so beautifully drawn and animated, like a cartoon come alive.
I love the Metal Slug series, they are the only arcade games that I can actually complete in a real arcade xD
Crazy story, one time at Taito Hey (highly recommended retro arcade in Akihabara) I saw a dude completing Metal Slug X with two characters at once, one which each hand, with zero deaths o_O
Garou, maybe. And Waku Waku 7.
Last Blade 2 is also a standout. Samurai Showdown 3 and 4 are nicely animated too.