Trixter: Blast Processing wasn't just fluff after all

[Jorpho]

I can't vouch for the accuracy, but apparently Sega's marketing hype might not have been so out of touch after all.
http://trixter.wordpress.com/2008/12/05/blast-processing-101/

[Zebbe]

I think what Sega meant with "blast processing" was that the 7.67 MHz 16/32-bit processor is more powerful than the 3.5 16/8-bit processor of the SNES. Which it actually is, even if there is a fast power-up in Super Metroid and an intense STG stage in R2.

[Aussie2B]

Hah, blast processing. I frequently make cracks about it to this day. It was wholly a marketing gimmick through and through. Just as ISPs are talking about "Powerboost". I'd imagine legally there's gotta be something behind it, and in the case of the Genesis, I think they were mainly just referring to the fact that it has a faster processor than the competition.

[Clownzilla]

I have to tell you as a loyal Nintendo fan there are just some games that I have to play on the Genesis instead of the SNES. A good example the classic treasure Populous. Sure, the SNES has more colors but it just can't keep up with the speed of the Genesis. The SNES version is next to unplayable! I feel the exact same way about the EA sports lineup. Now, this is not necessarily due to "blast processing" but is due to a much better processor for speed sensitive games.

[Neb6]

Blast processing appears to be an implementation of the Blitter (the hardware accelerator in the Amiga and Atari STE machines that was prototyped in the Atari 8-bit computers).

Take a look at how the term is referenced in this Emulator programmer's forum:

Note the use of the word "Blitting":

http://www.aep-emu.de/PNphpBB2-file-viewtopic-t-19870.html


If you see terms like BitBlt, Blitter, Bimmer, or Bit Block Transfer, you're likely dealing with a blitter GPU.

[BricatSegaFan]

Dont the NEO-GEO and Genesis share the same cpu?

I mean look what the NEO-GEO is capable of with a 12mhz version of the same cpu. I guess its Super blast processing then lol.

[Neb6]

Dont the NEO-GEO and Genesis share the same cpu?

I mean look what the NEO-GEO is capable of with a 12mhz version of the same cpu. I guess its Super blast processing then lol.

You are correct!

A lot of people focus too much on the general-purpose CPU. But the real magic happens in the custom hardware and Graphics Processing Units.

For example, the Amiga 1000 (1985) and the Mac Classic (1984) both use a 68000. However, games look and play very differently on those two machines.

In the case of the Amiga, they added on a GPU that runs at three-and-a-half times the speed of the CPU and is able to interleave cycles with the 68000 so that the two never meet. That way, they can both work with the same memory and not argue over RAM.

In the case of the Neo Geo versus Genesis, you can see that the resolutions, colors, over-all palette, digital sample handling, number of sprites, and sprite sizes are much more impressive in the Neo Geo. That's not the 68000 doing that, it's the GPU and other specific-purpose processors taking care of those functions.

http://www.neo-geo.com/forums/showthread.php?18178-Neo-Geo-system-specs-and-console-comparison

http://dextremes.com/genesis/gen-spec.html

So the real secret is to find out just what's going on in those chips. I'm thinking that a programmer who's done work on emulating the Neo Geo ought to be able to shed some light on this.

[Jorpho]

Commonly cited now (see ref. 57 at http://en.wikipedia.org/wiki/Sega_Genesis#cite_note-retrogamer-61) is that one day one Scot Bayless happened to say 'blast data into the DACs', at the marketers went nuts.

[Neb6]

Commonly cited now (see ref. 57 at http://en.wikipedia.org/wiki/Sega_Genesis#cite_note-retrogamer-61) is that one day one Scot Bayless happened to say 'blast data into the DACs', at the marketers went nuts.

Isn't a DAC just a Digital to Analog Converter? I have to wonder about this story since the only DACs that I'm aware of in the Genesis are for audio.

[Jorpho]

I'm thinking Blast is just another variation on Blit or Blitter (Bit Block Transfer device) for the purposes of providing hardware-accelerated graphics. Yes, you said that already.

It's hard to tell if the poster in that thread (whose link you edited out?) is being serious. But if you are for some reason interested in getting to the bottom of the matter:

Later a lawsuit involving infringements of blast processing related patents was settled out of court in Atari's favor.The patents in question are surely a matter of public record. Depending on what level the lawsuit reached, it might be a matter of public record too. http://en.wikipedia.org/wiki/Blitter cites US4874614 .

[Jack_Burton_BYOAC]

There are plenty of SNES games which use very fast scrolling. The opening stage of R-type III.

There are a couple of stages in Brutal Mario (smw hack) that scroll VERY FAST. As fast as anything I saw on the Genesis.

Honestly, I think both systems (and the NES and many more) are perfectly capable of scrolling the screen far faster than a player would ever be able to play a game.

[genesisguy]

There are plenty of SNES games which use very fast scrolling. The opening stage of R-type III.

There are a couple of stages in Brutal Mario (smw hack) that scroll VERY FAST. As fast as anything I saw on the Genesis.

Honestly, I think both systems (and the NES and many more) are perfectly capable of scrolling the screen far faster than a player would ever be able to play a game.

I agree to some extent. Take the Shoot Em Up genre on both the SNES and Genesis. Things scroll along nicely on Gradius III or Super R-Type, until things start blowing up on the screen and the game comes to a screeching halt. I notice less of that slow down on the Genesis shooters.

[SparTonberry]

"Why did Sega not call it DMA?"

The same reason I hear there's some nerds that would go nuts if you told them the GBA has Mode 7 graphics! :D

[blue lander]

I had always read that "blast processing" was just turning off interrupts on the CPU during vertical blanking interval, allowing the CPU to process more data. It makes more sense that there was a blitter doing DMA. Odd he considers the original 68000 to be a 32 bit CPU, though, it's more of a 16/32 bit hybrid.

[JohnHall]

funny how a marketing phrase just confuses the hell out of people. It was brilliant. Without this marketing nobody would've recognized the strengths of the Sega Genesis. You have to toot your own horn, no time to be humble when selling stuff.

[Ed Oscuro]

http://trixter.oldskool.org/2008/12/05/blast-processing-101/#comment-7884

SNES does DMA too. Genesis might do that better than the SNES. But the SNES' "slower" CPU hits far above its "weight" (clock speed).

Also:
http://trixter.oldskool.org/2008/12/05/blast-processing-101/#comment-8159

[BricatSegaFan]

There are plenty of SNES games which use very fast scrolling. The opening stage of R-type III.

But none of those games have Sonic the hedgehog ;) (officially)

[Ed Oscuro]

Thank goodness.

[Neb6]

I had always read that "blast processing" was just turning off interrupts on the CPU during vertical blanking interval, allowing the CPU to process more data. It makes more sense that there was a blitter doing DMA. Odd he considers the original 68000 to be a 32 bit CPU, though, it's more of a 16/32 bit hybrid.

If Blast Processing actually is referring to Blit operations then I can understand why there isn't a lot of documentation on the blitter from SEGA. Commodore went as far as to define Blitter for legal purposes. I think the only reason Atari got away with adding a Blitter to the STE and later machines was because Atari helped pay for the Amiga's development. Likely some kind of legal loophole there somewhere.

I was surprised in the very early 1990s when an engineer from ATI actually admited to me that the hardware acceleration in the ATI Mach series of cards was based on the Amiga Blitter (albeit a bit half-baked). So, I would imagine a host of companies were all finding ways to transfer blocks of graphics as efficiently as possible with a hardware device that had it's own dedicated Direct Memory Access to some kind of video RAM. Then 3D came along and turned (almost) everyone's attention away from 2D gaming.

After doing some more searching, I found references to the process of blitting from the 1970s. Sounds like Jay Miner's time at Atari and Amiga Corporation led to that technology being refined and brought to a home computing format.

[Ed Oscuro]

Blitters can be specialized hardware, but I am quite sure the name has been used (wrongly) in reference to software or hardware functionality generic to microprocessors.

The idea of a blitter seems to me nearly as basic as converting binary to decimal - but the USPTO awarded a patent for the blitter (http://www.google.com/patents?id=n_M9AAAAEBAJ&printsec=abstract&zoom=4&vq=blitter&dq=blitter&as_drrb_ap=b&as_minm_ap=1&as_miny_ap=1970&as_maxm_ap=1&as_maxy_ap=1990&as_drrb_is=q&as_minm_is=1&as_miny_is=2008&as_maxm_is=1&as_maxy_is=2008#v=onepage&q=blitter&f=false) but not for decimal-to-binary translation. In the patent, as I suspected, the blitter is basically acknowledged as taking off from the idea of DMA, appearing essentially as a DMA variant.

More to the point, a system does NOT need a blitter - which quickly transfers data in blocks to the screen - in order to function. It's an extra expense, either a modification to the off-the-shelf microprocessors used in these consoles but which are designed to be used with a family of support chips, or a new component.

The Genesis probably doesn't have a blitter at all. Reportedly the SNES doesn't and some cartridges have implemented a basic blitter as an assist chip.

[Neb6]

The Genesis probably doesn't have a blitter at all. Reportedly the SNES doesn't and some cartridges have implemented a basic blitter as an assist chip.[/QUOTE]

Well, according to this Genesis emulator programming change-list, it looks like the Genesis does have a blitter:

http://www.aep-emu.de/PNphpBB2-file-viewtopic-t-19870.html

Performing shifting and masking operations on a 68000 CPU draws far too many cycles for it to be anywhere close to being efficient. That had already been proven on the earlier 6809. As for DMA, that's just direct memory access for whatever piece of hardware for the purposes of freeing up CPU cycles.

[Jorpho]

Yes, you linked to that before. Rather than speculating, you could just, y'know, ask the emulator author. If it's really a hardware feature of the Genesis, shouldn't there be references to it in a whole lot of other emulator documentation?

The first time I read about blitting was in conjunction with WinG (http://en.wikipedia.org/wiki/WinG) (links to http://en.wikipedia.org/wiki/Bit_blit ), which does not inherently require hardware.

[Niku-Sama]

for some reason this isnt new to me......


i feel old now

[Neb6]

Yes, you linked to that before. Rather than speculating, you could just, y'know, ask the emulator author. If it's really a hardware feature of the Genesis, shouldn't there be references to it in a whole lot of other emulator documentation?

The first time I read about blitting was in conjunction with WinG (http://en.wikipedia.org/wiki/WinG) (links to http://en.wikipedia.org/wiki/Bit_blit ), which does not inherently require hardware.


Well, there's always this:

http://www.google.ca/patents/US5880739

Search word = Sega

[Ed Oscuro]

Okay, I forgot about the VDP, too, which is probably used for blitting functions. Point about the 68000 being slow for scanline and other operations without a blitter.

@ Jorpho: "Blitting" can be done in software, sure, but a blitter would be hardware.

In the case of the Sega patent filing above, that looks like an early 3D era patent, where a blitter (or some kind of other means of getting pixel fill rate going) is absolutely necessary, unquestionably.

[Neb6]

Okay, I forgot about the VDP, too, which is probably used for blitting functions. Point about the 68000 being slow for scanline and other operations without a blitter.

@ Jorpho: "Blitting" can be done in software, sure, but a blitter would be hardware.

In the case of the Sega patent filing above, that looks like an early 3D era patent, where a blitter (or some kind of other means of getting pixel fill rate going) is absolutely necessary, unquestionably.

The SEGA patent that the Compaq Blitting patent is referencing seems to be describing something that sounds a lot like the Genesis/Mega Drive version of Sonic:
http://www.google.ca/patents/US5513307

See figures 17, 20A, and 43A.

Excerpts:

"It is possible that the character could jump while in the process of traversing the shuttle loop. Since the sloop twists like a corkscrew, the result of such a player jump could be that, rather than going upward, the character falls down off the loop. For example, if the character jumps from the left inclined or twisted side of the loop as the sprite runs to the right, the character will end up falling downward rather than jumping upward as indicated by the trajectory shown by arrow 120 in FIG. 16C. In that case, the horizontal speed of the character is maintained, as he falls downward. If, on the other hand, the character jumps while on the inclined portion on the right side of the shuttle loop as it runs to the left, then it will be seen to follow the trajectory 122 as its horizontal speed to the left is maintained and as it falls downward. Its fall will be stopped when it hits the surface 124."

"race through the playfield trying to accumulate points by surmounting obstacles, slaying enemies or gathering "magical rings", for example.

[blue lander]

I wrote a little "space invaders" style game for the Genesis about 10 years ago for fun so my memories on this are a little fuzzy, but as I recall you could do basic bit blitting with the GPU. Like, you could have it shift a bunch of data at once, or move a block of data from RAM to VRAM. It was pretty simple compared to what an Amiga could do. Useful for scrolling but not much else.

[ccovell]

I wrote a little "space invaders" style game for the Genesis about 10 years ago for fun so my memories on this are a little fuzzy, but as I recall you could do basic bit blitting with the GPU. Like, you could have it shift a bunch of data at once, or move a block of data from RAM to VRAM. It was pretty simple compared to what an Amiga could do. Useful for scrolling but not much else.

But... that's just DMA transfer. IIRC, the SNES and TG-16 can both do DMA, block transfers, high-speed VRAM-to-VRAM transfers, etc. I think the difference between block moves and "blitting" is that in blitting you can combine bitmap data from one source, logically AND or OR it with a mask, and then overlay the product on some destination bitmap. <--- the Amiga did this in hardware.

I have my doubts the Genesis could do that in hardware. If it was done in software, then "blast processing" remains bullshit as any game console can do any kind of processing in software.

[blue lander]

I think you could do bit level shifts, but I don't remember any fancier data transformation abilities. It was more like an off-the-shelf MMU. It reminded me a little of the Atari ST.

Zophars domain used to have a really good document on how the VDPs in the Genesis and SMS worked, I'm sure it's still out there somewhere.

[TonyTheTiger]

I have my doubts the Genesis could do that in hardware. If it was done in software, then "blast processing" remains bullshit as any game console can do any kind of processing in software.

Depends on how you define "bullshit." Something can be technically true even if it isn't all that special or downright insignificant. Given that this era in particular was notorious for relatively meaningless buzzwords in general (the entire bit wars come to mind) "blast processing" doesn't seem any worse than all the rest of the marketing shenanigans that went on.

http://imgs.xkcd.com/comics/free.png

[Jorpho]

Zophars domain used to have a really good document on how the VDPs in the Genesis and SMS worked, I'm sure it's still out there somewhere.Probably http://www.romhacking.net/documents/231/ ? See also the other Genesis docs (http://www.romhacking.net/?page=documents&category=&platform=11&game=&author=&perpage=20&level=&title=&desc=&docsearch=Go).