Based on a educated guess, console development cost. Thanks

[SegaR&D]

The SH-4 had alot of our input put into it.

 

[Ty]

The SH-4 had alot of our input put into it.

Such as?

 

[PC-Engine]

But after that it was used in everything from video game systems to microwaves to tvs . Even some palm pilots and caculators .

Yep makes sense. That's why I consider the SH-4 to be equally custom as the Gekko not more not less. It wasn't a processor designed to be in microwaves from the start, it was for DC, NAOMI 1&2.

 

[Fox5]

The SH-4 had alot of our input put into it.

Such as?

"Make it good. REAL good."

 

[Ty]

Yep makes sense. That's why I consider the SH-4 to be equally custom as the Gekko not more not less. It wasn't a processor designed to be in microwaves from the start, it was for DC, NAOMI 1&2.

Well the argument about "more or less custom" is a silly one really simply because no one has defined what makes A more or less "custom" than B.

Please go ahead and give us your definition of "custom", THEN we can talk about it.

 

[PC-Engine]

Yep makes sense. That's why I consider the SH-4 to be equally custom as the Gekko not more not less. It wasn't a processor designed to be in microwaves from the start, it was for DC, NAOMI 1&2.

Well the argument about "more or less custom" is a silly one really simply because no one has defined what makes A more or less "custom" than B.

Please go ahead and give us your definition of "custom", THEN we can talk about it.

That's archie4oz's responsibility not mine since he claimed that the Gekko is more custom than the SH-4

 

[V3]

Yep makes sense. That's why I consider the SH-4 to be equally custom as the Gekko not more not less. It wasn't a processor designed to be in microwaves from the start, it was for DC, NAOMI 1&2.

Are you guys arguing about off the shelf Vs custom components ?

or if the component is design specifically for a systems ?

If it is the former, than any components you and I can buy is consider off the shelf components. Like Emotion Engine, I think you can buy that from Toshiba, for your own use, so I consider that off the shelf components.

If it is the later, than XCPU is custom too.

 

[PC-Engine]

Yep makes sense. That's why I consider the SH-4 to be equally custom as the Gekko not more not less. It wasn't a processor designed to be in microwaves from the start, it was for DC, NAOMI 1&2.

Are you guys arguing about off the shelf Vs custom components ?

or if the component is design specifically for a systems ?

If it is the former, than any components you and I can buy is consider off the shelf components. Like Emotion Engine, I think you can buy that from Toshiba, for your own use, so I consider that off the shelf components.

If it is the later, than XCPU is custom too.

My thoughts exactly, that's why archie4oz's nitpicking is pointless not to mention annoying...

Anyway in the case of Gekko, it was an existing chip that was already available on the market and used in various devices. That chip was then modified to be used in GCN. Cache was increased and instructions were added.

For SH-4, it was in development as a successor to the SH-3 and was intended for use as a general purpose RISC chip for various devices none of which required strong FP performance. Then SEGA came to Hitachi and said they wanted to use the SH-4 in a new console so Hitachi had to increase the FP performance from the original in progress design (it had to be able to transform several million polys/sec) as well as adding special instructions.

 

[I.S.T.]

Actually, the XCPU is just a Mobile Celly from that era, IIRC. I read it here, lol.

 

[Fafalada]

back to your old ways of splitting hairs...again...

Nope, he's just comparing stuff the docs say for both CPUs. You can call it splitting hairs, but ultimately the customization IS measured by technical details.

Afaik SH4 was just as much off the shelf as other SHs and Rxxxs were in other consoles before and after. Grab a design, modify it a bit, and stuff it in the box. Gekko is more of the same, just that it builds on a non Mips/Hitachi design for a change.
The extent of the modifications on both chips is all documented in the CPU docs, and that's what Archie was comparing.

 

[PC-Engine]

back to your old ways of splitting hairs...again...

Nope, he's just comparing stuff the docs say for both CPUs. You can call it splitting hairs, but ultimately the customization IS measured by technical details.

Afaik SH4 was just as much off the shelf as other SHs and Rxxxs were in other consoles before and after. Grab a design, modify it a bit, and stuff it in the box. Gekko is more of the same, just that it builds on a non Mips/Hitachi design for a change.
The extent of the modifications on both chips is all documented in the CPU docs, and that's what Archie was comparing.

Ok so what makes one more custom than the other according to the docs? Does the Gekko docs say "Gekko was designed to be more custom than SH-4"? Got details?

I've got 10 more instructions than YOU!! I AM MORE CUSTOM!! TAKE THAT YOU WEAK SH-4!! Muahahaha!!!

 

[archie4oz]

well for starters...

What was the SIMD unit used for in these products?

It doesn't *have* a SIMD unit, it maps SIMD instructions over the FPU registers... (actually just like Gekko)

I thought the SH-4 was used in many applications even including such mundane appliances as microwave ovens!

No, those would more likely be built with SH-1, SH-2 microcontrollers..

SH-4 core was probably a request from SEGA since the SIMD vector unit would only be required for stuff like 3D. In that respect the SH-4 was a completely customized core based on the Super Highway ISA tailored specifically after SEGA's needs.

This would be false... The SH-4 was already in development. Yes SEGA had significant input however the SIMD capability was not the sole input of SEGA. The chip was being targetted for set-top boxes (the DC being one, cable boxes, satellite receivers being others) to begin with, as well as hand-held PCs, routers, etc...

Also, the SIMD instructions have more use than just 3D... You can use them for handling audio (e.g. echo-cancellation in VoIP routers, voice recognition algorithms) and video (deblock, convolution, etc) processing filters, image/video stream decode/decompression...

Looks like hataci / sega beat sony to the cell computing

You could say the same thing about MIPS, PowerPC, SPARC, x86, M88k, M68k...

Pretty sure it's just less cache, unneeded instructions removed, and a nintendo customized version of what is probably similar to SSE.

actually it's the same level cache as the 750CX line... No instructions removed (actually added instead)... Additional parallel arithmatic instructions for pack-single processing on the FPU, and a slew of load/store instructions for packed loads and stores, cache manipulation (comparable to a 7450, with cache-locking and DMA), and an actual DMA queue and a write gather pipe...

If it is the later, than XCPU is custom too.

Nope, it's about as COTS as you can get... It just has a unique S-code to distinguish it...

Like Emotion Engine, I think you can buy that from Toshiba, for your own use, so I consider that off the shelf components.

You cannot... The TX-079 was a spinnoff of the EE that Toshiba offers, but it's not an EE, it's basically just what composes the EEcore...

Anyway in the case of Gekko, it was an existing chip that was already available on the market and used in various devices. That chip was then modified to be used in GCN. Cache was increased and instructions were added.

No cache increase... However the 750CX/CXe *was* an existing desktop CPU in it's midlife stage.

For SH-4, it was in development as a successor to the SH-3 and was intended for use as a general purpose RISC chip for various devices none of which required strong FP performance.

You were correct until you got to the FP performance part...

Afaik SH4 was just as much off the shelf as other SHs and Rxxxs were in other consoles before and after. Grab a design, modify it a bit, and stuff it in the box. Gekko is more of the same, just that it builds on a non Mips/Hitachi design for a change.

Somewhat, but not quite... While there are external difference between variations of SH-4s (the nature of embedded processors) such as memory controllers, external interfaces, ports, etc., the core is essentially the same as any other SH-4 model. I.e. code compiled (ABI withstanding) for the SH-7709 (DC), will pretty much run fine on any of the other SH-775x/776x... Ergo, the 7709 doesn't have any instructions not present in other SH-4s (excluding some of the newer sythesized non-FPU designs).

On Gekko, OTOH has a lot of changes to the core that makes it different from the rest of the 750 line. No other PowerPC in the 750 line has a write-gather pipe attached to the LS pipe, or the DMA queue. Also no 750 has Gekko's cache locking features, loadQ, storeQ intructions, or any of the packed FP ALU instructions... You compile something for (say fictional gcc flag -mcpu=gekko mtune=750) and try to run that on any other PowerPC 750 (or any PowerPC for that matter, again ABI withstanding) you're program is likely to crash...

 

[Fox5]

Actually, the XCPU is just a Mobile Celly from that era, IIRC. I read it here, lol.

And I believe the dreamcast sh-4 beats it, or about equals it in float point performance.(depending on if sse is used or not) Good thing xbox has t&l, huh?

BTW, if xcpu was at all custom, would it be possible for modders to drop a p3 into it and have perfect compatibility, or a p4 celeron and have partial compatibility?

 

[archie4oz]

And I believe the dreamcast sh-4 beats it, or about equals it in float point performance.(depending on if sse is used or not) Good thing xbox has t&l, huh?

As long as you stick to packed-float math ops... Anything scalar and the Xbox cpu will stomp all over the SH-4 (it has clock, cached, and much more extensive OOE going for it)... That being said, I still like the SH-4 better...

 

[I.S.T.]

We all know of your love of the SH-4. We've all seen the pics of your torred love affair with it. Your screams of how good of a....CPU it is. j/k I couldn't resist after seeing that.

 

[Ty]

That's archie4oz's responsibility not mine since he claimed that the Gekko is more custom than the SH-4

Actually I think you brought it up first with the following:

Sonic knows how much it cost to develop DC so GCN should be similar they're both using basically off-the-shelf parts.

Where your phrase, "off-the-shelf" refers to the amount of customization or lackthereof for the various parts.

Anyhow looks like Archie answered it far better than any of us could.

 

[Crazyace]

There are instruction differences between the standard SH4, and the variant in the DC - specifically to aid 3D transformation.. not a lot of extra instructions, but enough to make it a 'custom chip' for Sega.

 

[PC-Engine]

Actually I think you brought it up first with the following:

Where your phrase, "off-the-shelf" refers to the amount of customization or lackthereof for the various parts.

And?

REREAD what I said!

Sonic knows how much it cost to develop DC so GCN should be similar they're both using basically off-the-shelf parts.

What does this mean in english? I'll let you figure it out...

And when you figure it out you won't be back here with another response unless you're in denial....get over it.

 

[ShinHoshi]

Just wondering...

->The Gekko has the 64bit CPU from the 750 series split in two (2Floating Point Operations/Cycle).

->The XCPU has the 128 SSE unit (4Floating Point ops/cycle) + the FPU (80 bits) that shares its registers with MMX units... (can be used at the same time FPU/SSE ? I know that's not the case with MMX/FPU since they share registers but what about SSE ?)

->And the DC what has ? Can anybody explain me in what consists fp pushing power in the DC ? Please relate to SIMD, FPU units, size and ops.

Thanks.

 

[Ty]

And?

REREAD what I said!

Sonic knows how much it cost to develop DC so GCN should be similar they're both using basically off-the-shelf parts.

What does this mean in english? I'll let you figure it out...

It means you first brought up the comparison of the amount customization or lack thereof for the various chips. Which Archie then corrected you by laying out the differences in more detail.

And when you figure it out you won't be back here with another response unless you're in denial....get over it.

Are you always so angry?