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Jan 27 2013
By: JonathanCarabalo Lombax Warrior 220 posts
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Write-Gather pipes on the Gekko CPU

5 replies 441 views Edited Jan 27, 2013

There's an interesting feature of the Gamecube's CPU.  A 128-byte Write-Gather, FIFO pipeline that transfers data in bursts to the main memory.  The memory transfer problem is a big one.  The main bus is inherently limited in the degree to which it can transfer data, in that each transfer utlizes the main bus completely - blocking other devices from using it.  The write-gather pipe bursts the data on the pipeline, when it is full. 

 

The Playstation 2 uses a separate path from the CPU to the GPU - another interesting solution.

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Fender Bender
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Re: Write-Gather pipes on the Gekko CPU

Jan 27, 2013
I'm starting to think you are some form of weird spambot.
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First Son
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Re: Write-Gather pipes on the Gekko CPU

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Feb 11, 2013


i think your WAY OFF MY FRIEND ... the fifo data burst pipes is a graphics data burst pipe with maximum data compression of 4to1 , the gekko and broadway and expresso cpus all support 4to1 max data compression this data is real time decompressed by cpu and gpu its a amazing ability as it allows 4 x more data to pass and it also allows the catch memory to deal with inward data instead of inward and outward data so this increasing the catch size and ability for in coming data...

having a fifo data pipeline plus data compression gives the cpu and gpu a great advantage...

also data compression at peak 4to1 allows bus ,catch, cpu ram,disc ALL TO HOLD AND STREAM 4 X AS MUCH DATA AS NO COMPRESSION EXPRESSO MAINTAINS THIS ABILITY!!!!

EXPRESSO CPU CATCH @ PEAK 4TO1 DATA COMPRESSION IS A 12 MB CATCH

the bus allows 4x more data the ram also and of course the disc every part is now 4x as effective due to data compression 2to1 and 4to1 are supported

the fifo data pipe also supports 4x compression so512 not 128 goes to gpu for real time decompression and processing

NOW WILL WIIUS SHADERS SUPPORT IT VERY INTERESTING

now another ability i think wiiu will maintain maybe improve on VIRTUAL TEXTURE DESIGN

As well as texture compression wii and GC supported virtual texture design this allowed a futher breakdown of texture data increasing texel thru put by 50% so 4 texture units became 6 effective so 1mb of textures became 1.5

so at full 6x compression a meg would hold 6mb plus another 50% virtual compression so thats peak 9mb of texture data due to VIRTUAL TEXTURE DESIGN wiiu will have this ALSO...

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Lombax Warrior
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Re: Write-Gather pipes on the Gekko CPU

Feb 11, 2013

Oh yes I know about the 4:1 data compression.  But it's only useful for certain situations.  Such as when the data to be altered is slight enough - and doesn't require such precision.  Floating-point value locations, for the vertices, are one instance.  If there's only a slight alteration to be made.  It's not that useful.  Plus - it has to be decompressed on the fly out of the cache.  

 

SSE1-3 supports pack and unpack instructions for floating-point data - this is not a unique feature.  By the way.  What is unique is the write-gather pipe which bursts to memory.   

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PIayStation MVP
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Re: Write-Gather pipes on the Gekko CPU

Feb 11, 2013

JonathanCarabalo wrote:

There's an interesting feature of the Gamecube's CPU.  A 128-byte Write-Gather, FIFO pipeline that transfers data in bursts to the main memory.  The memory transfer problem is a big one.  The main bus is inherently limited in the degree to which it can transfer data, in that each transfer utlizes the main bus completely - blocking other devices from using it.  The write-gather pipe bursts the data on the pipeline, when it is full. 

 

The Playstation 2 uses a separate path from the CPU to the GPU - another interesting solution.


In the end it is the quality of games that counts. The reason I purchased my GameCube was because of games like Rouge Squadron 2&3, Resident Evil Remake & 0, and Metal Gear Solid the Twin Snakes. Except for the the RE games, they have yet to hit another platform. Other than the Nintendo produced games and the games I just mentioned, there was little else that was on the Gamecube that couldn't be found on the PS2 & Xbox....

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First Son
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Re: Write-Gather pipes on the Gekko CPU

Mar 12, 2013


toki tori 2 devs have stated the game uses 100mb of ram less than ps3 x360 WHY whatsvthe trick well theres data compression thru out the system 4to1 peak that no other consoles have and VIRTUAL texture this would save huge amounts of memory too...

how they did this ,what trick wiiu has wasnt revealed but its there

wiiu has 70x more catch/buffer ram on the gpu than ps4 ...

ps4 has 8gig main ram vs wiius 2gig but the wiiu is ULTRA EFFICENT and has 70x more on chip fast ram than ps4s gpu

ps4 gpu catch 512k ...wiius 32mb edram ,2mb edram,1mb sram thats 35mb total 70x more than ps4

so fanboys might brag ps4s ram is 4x wiiu

but wiiu fans could say wiius gpu catch,buffer size is 70x ps4s

wiiu will be based around ultra efficency and tricks and high speed ram

ps4 is brute forcing like a pc and runs very slow vs wiiu in ram speed it will also read write with main memory far far far more than wiiu

wiiu will do far far more on chip in catch memory and at a higher speed LATENCY

so theres no graphics argument its all saturation level now stating wiiu cannot run ps4 level games is BS

virtual texture design applys to all ram buses catches and texture units to increase texture performance

data compression again applys to ram bus catch and cpus

latency super fast comunication and freedom from bottlenecks again increases thru put ..

wiiu will do it the nintendo way sonys going the pc root

toki tori developers have saved a huge amount of ram porting to wiiu from say x360 the same will apply porting from pc ps4 and xbox durrango

the tricks in wiiu all started out in the gamecube and will be far better now than then

wiiu hits main ram far far less than ps4 will do also its a clever clean fast design

ps4 is clearly a pc

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