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IBM's PPC being open sourced .. what does this mean for embedded devices ?

Started by kristoff September 16, 2019
HI all,


I know is this kind-of old news by now, but -as far as I see- this has 
not been discussed here:

IBM is open-sourcing their PowerPC processor design.

(E.g. see here and other links:)
https://www.eejournal.com/article/ibm-gives-away-powerpc-goes-open-source/)


As PowerPC processors do are used in embedded devices, anybody any idea 
what this would mean for the embedded-processor market?
Are we now going to be flooded by Chinese ppc-based devboards?
And is this going to kill the risc-v?



BTW.
Does anybody have an easy-to-use overview of different powerPC 
architectures out there? (especially for embedded use)

I've been trying to understand the different wikipedia pages on the 
powerPC architectures, but it all seams to one giant mix of names, 
numbers and 'books' from a dozen different companies.



Cheerio!
Kr. Bonne,
On 9/16/2019 21:36, kristoff wrote:
> HI all, > > > I know is this kind-of old news by now, but -as far as I see- this has > not been discussed here: > > IBM is open-sourcing their PowerPC processor design. > > (E.g. see here and other links:) > https://www.eejournal.com/article/ibm-gives-away-powerpc-goes-open-source/) > > > As PowerPC processors do are used in embedded devices, anybody any idea > what this would mean for the embedded-processor market? > Are we now going to be flooded by Chinese ppc-based devboards? > And is this going to kill the risc-v?
If someone takes on and starts making more power architecture processors the impact could be huge, this is by far the best architecture I have seen in my life - and I have explored most of them (and used power for decades now). Then it might make no impact at all, how many of those making decisions of such magnitude can see further than the next quarter report and can look into something other than what "everybody is doing".
> > > > BTW. > Does anybody have an easy-to-use overview of different powerPC > architectures out there? (especially for embedded use) > > I've been trying to understand the different wikipedia pages on the > powerPC architectures, but it all seams to one giant mix of names, > numbers and 'books' from a dozen different companies.
The only maker of Power architecture processors is NXP (since they acquired Freescale). IBM had an embedded core some ages ago, 401 or something like that, which some other company - AMCC I think - took on but I never used any of these.
> > Cheerio! > Kr. Bonne,
Thanks for posting, I had missed the news so this is new to me. Good news I suppose, gives some hope that this great architecture will survive after all. Hopefully I can migrate DPS to 64 bit power sooner rather than later, I have been wanting to do it for quite some time now. Might also be some help. Dimiter ====================================================== Dimiter Popoff, TGI http://www.tgi-sci.com ====================================================== http://www.flickr.com/photos/didi_tgi/
On Monday, September 16, 2019 at 4:24:40 PM UTC-4, Dimiter wrote:
> On 9/16/2019 21:36, kristoff wrote: > > HI all, > > > > > > I know is this kind-of old news by now, but -as far as I see- this has > > not been discussed here: > > > > IBM is open-sourcing their PowerPC processor design. > > > > (E.g. see here and other links:) > > https://www.eejournal.com/article/ibm-gives-away-powerpc-goes-open-source/) > > > > > > As PowerPC processors do are used in embedded devices, anybody any idea > > what this would mean for the embedded-processor market? > > Are we now going to be flooded by Chinese ppc-based devboards? > > And is this going to kill the risc-v? > > If someone takes on and starts making more power architecture processors > the impact could be huge, this is by far the best architecture I have > seen in my life - and I have explored most of them (and used power for > decades now). > Then it might make no impact at all, how many of those making decisions > of such magnitude can see further than the next quarter report and > can look into something other than what "everybody is doing". > > > > > > > > > BTW. > > Does anybody have an easy-to-use overview of different powerPC > > architectures out there? (especially for embedded use) > > > > I've been trying to understand the different wikipedia pages on the > > powerPC architectures, but it all seams to one giant mix of names, > > numbers and 'books' from a dozen different companies. > > The only maker of Power architecture processors is NXP (since they > acquired Freescale). IBM had an embedded core some ages ago, 401 > or something like that, which some other company - AMCC I think - took > on but I never used any of these. > > > > > Cheerio! > > Kr. Bonne, > > Thanks for posting, I had missed the news so this is new to me. > Good news I suppose, gives some hope that this great architecture > will survive after all. > > Hopefully I can migrate DPS to 64 bit power sooner rather than > later, I have been wanting to do it for quite some time now. Might also > be some help.
Maybe I'm not remembering it right, but I thought the PPC fell out of favor because as processors got faster and more complex, the PPC architecture lost it's advantages. I would seem I am not remembering this correctly. So why did the PPC architecture stop being developed? Is this still a competitive architecture in general? I'm guessing it is still competitive in lower end processors for sure. How does it stack up to MIPS? Isn't that one also open source? Or was that open sourced only in a very limited way? -- Rick C. - Get 2,000 miles of free Supercharging - Tesla referral code - https://ts.la/richard11209
On 9/17/2019 5:11, Rick C wrote:
> On Monday, September 16, 2019 at 4:24:40 PM UTC-4, Dimiter wrote: >> On 9/16/2019 21:36, kristoff wrote: >>> HI all, >>> >>> >>> I know is this kind-of old news by now, but -as far as I see- this has >>> not been discussed here: >>> >>> IBM is open-sourcing their PowerPC processor design. >>> >>> (E.g. see here and other links:) >>> https://www.eejournal.com/article/ibm-gives-away-powerpc-goes-open-source/) >>> >>> >>> As PowerPC processors do are used in embedded devices, anybody any idea >>> what this would mean for the embedded-processor market? >>> Are we now going to be flooded by Chinese ppc-based devboards? >>> And is this going to kill the risc-v? >> >> If someone takes on and starts making more power architecture processors >> the impact could be huge, this is by far the best architecture I have >> seen in my life - and I have explored most of them (and used power for >> decades now). >> Then it might make no impact at all, how many of those making decisions >> of such magnitude can see further than the next quarter report and >> can look into something other than what "everybody is doing". >> >>> >>> >>> >>> BTW. >>> Does anybody have an easy-to-use overview of different powerPC >>> architectures out there? (especially for embedded use) >>> >>> I've been trying to understand the different wikipedia pages on the >>> powerPC architectures, but it all seams to one giant mix of names, >>> numbers and 'books' from a dozen different companies. >> >> The only maker of Power architecture processors is NXP (since they >> acquired Freescale). IBM had an embedded core some ages ago, 401 >> or something like that, which some other company - AMCC I think - took >> on but I never used any of these. >> >>> >>> Cheerio! >>> Kr. Bonne, >> >> Thanks for posting, I had missed the news so this is new to me. >> Good news I suppose, gives some hope that this great architecture >> will survive after all. >> >> Hopefully I can migrate DPS to 64 bit power sooner rather than >> later, I have been wanting to do it for quite some time now. Might also >> be some help. > > Maybe I'm not remembering it right, but I thought the PPC fell out of favor because as processors got faster and more complex, the PPC architecture lost it's advantages. I would seem I am not remembering this correctly.
The architecture did not lose its advantages, it is just as silicon got faster messy designs like the x86 could run fast enough for the general population. I don't know how far did IBM go developing it, may be they still do. I know only the Motorola/Freescale line, some of which I have used and am using. Their latest designs are 64 bits QORIQ (someone got away without being punished for that name) which look quite good really.
> > So why did the PPC architecture stop being developed? Is this still a competitive architecture in general? I'm guessing it is still competitive in lower end processors for sure. How does it stack up to MIPS? Isn't that one also open source? Or was that open sourced only in a very limited way? >
MIPS looks like a smaller scale power, I have not used it, just looked at it. No idea if it is open source. Microchip make some 32 bit MCU-s with MIPS, I have not heard people using them complain. Dimiter
On Tuesday, September 17, 2019 at 12:11:05 AM UTC-4, Dimiter wrote:
> On 9/17/2019 5:11, Rick C wrote: > > On Monday, September 16, 2019 at 4:24:40 PM UTC-4, Dimiter wrote: > >> On 9/16/2019 21:36, kristoff wrote: > >>> HI all, > >>> > >>> > >>> I know is this kind-of old news by now, but -as far as I see- this has > >>> not been discussed here: > >>> > >>> IBM is open-sourcing their PowerPC processor design. > >>> > >>> (E.g. see here and other links:) > >>> https://www.eejournal.com/article/ibm-gives-away-powerpc-goes-open-source/) > >>> > >>> > >>> As PowerPC processors do are used in embedded devices, anybody any idea > >>> what this would mean for the embedded-processor market? > >>> Are we now going to be flooded by Chinese ppc-based devboards? > >>> And is this going to kill the risc-v? > >> > >> If someone takes on and starts making more power architecture processors > >> the impact could be huge, this is by far the best architecture I have > >> seen in my life - and I have explored most of them (and used power for > >> decades now). > >> Then it might make no impact at all, how many of those making decisions > >> of such magnitude can see further than the next quarter report and > >> can look into something other than what "everybody is doing". > >> > >>> > >>> > >>> > >>> BTW. > >>> Does anybody have an easy-to-use overview of different powerPC > >>> architectures out there? (especially for embedded use) > >>> > >>> I've been trying to understand the different wikipedia pages on the > >>> powerPC architectures, but it all seams to one giant mix of names, > >>> numbers and 'books' from a dozen different companies. > >> > >> The only maker of Power architecture processors is NXP (since they > >> acquired Freescale). IBM had an embedded core some ages ago, 401 > >> or something like that, which some other company - AMCC I think - took > >> on but I never used any of these. > >> > >>> > >>> Cheerio! > >>> Kr. Bonne, > >> > >> Thanks for posting, I had missed the news so this is new to me. > >> Good news I suppose, gives some hope that this great architecture > >> will survive after all. > >> > >> Hopefully I can migrate DPS to 64 bit power sooner rather than > >> later, I have been wanting to do it for quite some time now. Might also > >> be some help. > > > > Maybe I'm not remembering it right, but I thought the PPC fell out of favor because as processors got faster and more complex, the PPC architecture lost it's advantages. I would seem I am not remembering this correctly. > > The architecture did not lose its advantages, it is just as silicon got > faster messy designs like the x86 could run fast enough for the general > population. > > I don't know how far did IBM go developing it, may be they still do. > I know only the Motorola/Freescale line, some of which I have used and > am using. Their latest designs are 64 bits QORIQ (someone got away > without being punished for that name) which look quite good really.
There has to be some reason why they lost the war other than marketing. Apple was using the PPC and many others. So there was clearly a market. Perhaps I didn't state things correctly. The advantages of the PPC must not have been significant enough in larger chips to make continued development of ever more expensive designs worthwhile. I recall when IBM dropped out of the race. They must have seen the handwriting on the wall. So how does Freescale keep paying for spins on 64 bit chips? I take it they still can hold a match to the Intel processors, rather they are now competing with the ARMs of the world?
> > So why did the PPC architecture stop being developed? Is this still a competitive architecture in general? I'm guessing it is still competitive in lower end processors for sure. How does it stack up to MIPS? Isn't that one also open source? Or was that open sourced only in a very limited way? > > > > MIPS looks like a smaller scale power, I have not used it, just looked > at it. No idea if it is open source. Microchip make some 32 bit MCU-s > with MIPS, I have not heard people using them complain.
Yeah, seems the open source thing is real... They seem to be saying MIPS has some real advantages over RISC-V but they may not last... "While RISC-V is gaining grown[sic] the storied history of MIPS means that the MIPS stack is far more complete, and includes things like DSP and SIMD extensions that still don’t exist for the RISC-V platform." I've read here that most MIPS designs are embedded cores in custom ASICs. So someone already loves them. Seems the current owners of the MIPS architecture think open sourcing the design will allow them to sell more IP solutions. -- Rick C. + Get 2,000 miles of free Supercharging + Tesla referral code - https://ts.la/richard11209
On 16/09/2019 20:36, kristoff wrote:
> HI all, > > > I know is this kind-of old news by now, but -as far as I see- this has > not been discussed here: > > IBM is open-sourcing their PowerPC processor design.
No, they are not (as far as I understand the situation). The linked article seems a bit mixed up as to what they are giving away (they are mixed up about RISC-V too). When talking about processor licensing, there are many levels. You can license the ISA - the instructions, register setup, instruction codings, etc. This is the minimum you need in order to make a cpu that will run binaries for that processor. You can license design files (Verlig, VHDL, etc.) for some or all of an implementation. You can license hard macros for some or all of an implementation. You can license the right to use names, trademarks, patents, etc. You can license the right to modify and expand on any of this. As far as I know, IBM has offered commercial licenses on all of these bits - just as ARM, MIPS, etc. do. Some customers have taken the ISA and made their own implementations, others have taken complete hard macros and put them on ASICs, others go somewhere in between. From this article, it seems IBM is giving free licensing for the ISA. That means you can make your own processor in an FPGA, ASIC, etc., that runs PowerPC code. It is not clear how open it is - do you need to obtain a zero-cost license? Can you modify the ISA as you want? What about naming - can you call it a PowerPC processor or PPC compatible, even if you add things to it? What about if you remove features? Will groups other than IBM, Apple and NXP be involved in the future of PowerPC and its ISA? It does not appear that they are giving away a usable /implementation/ of a PowerPC core. I'm guessing answers to all these points are to be found with a bit of research on the Linux Foundation or IBM's websites, but they need considered before it is clear what IBM have actually done here.
> > (E.g. see here and other links:) > https://www.eejournal.com/article/ibm-gives-away-powerpc-goes-open-source/) > > > As PowerPC processors do are used in embedded devices, anybody any idea > what this would mean for the embedded-processor market?
Mostly nothing, I think. PPC cores are used in a few specific embedded markets - primarily the automotive industry, and other tough industrial uses. They used to be popular in networking systems (along with MIPS), but ARM is taking over that niche. I think you will continue to get PPC-based devices from those that made them before (primarily NXP, with some second-source devices from ST). I don't think anyone is going to design a new implementation for new devices unless they are already invested in the PPC world. PPC simply does not have any advantages over alternatives, and it is a big and heavy ISA compared to RISC-V. What you might see is a few more second-source parts, perhaps also things like radiation-hard or high-temperature versions from folks like Atmel. And you might see it in use in systems that need a very fast processor and are willing to spend a lot of effort to get it, but want low production or licensing costs - maybe we'll see it again in games consoles, or chips designed specifically for supercomputers.
> Are we now going to be flooded by Chinese ppc-based devboards? > And is this going to kill the risc-v? >
No, it won't kill RISC-V. It will (in my humble and only somewhat informed opinion) aid RISC-V, by making "open source ISA" more acceptable to conservative and sceptical companies who viewed "open source ISA" as meaning "made by hobby developers" or "made by communists". When IBM says "open source ISAs are good", they are more likely to take note of other open source ISAs.
> > > BTW. > Does anybody have an easy-to-use overview of different powerPC > architectures out there? (especially for embedded use)
I'd be surprised if such a thing exists. There are /many/ PPC variations.
> > I've been trying to understand the different wikipedia pages on the > powerPC architectures, but it all seams to one giant mix of names, > numbers and 'books' from a dozen different companies. > > > > Cheerio! > Kr. Bonne,
On 17/09/2019 06:26, Rick C wrote:
> On Tuesday, September 17, 2019 at 12:11:05 AM UTC-4, Dimiter wrote: >> On 9/17/2019 5:11, Rick C wrote: >>> On Monday, September 16, 2019 at 4:24:40 PM UTC-4, Dimiter >>> wrote: >>>> On 9/16/2019 21:36, kristoff wrote: >>>>> HI all, >>>>> >>>>> >>>>> I know is this kind-of old news by now, but -as far as I see- >>>>> this has not been discussed here: >>>>> >>>>> IBM is open-sourcing their PowerPC processor design. >>>>> >>>>> (E.g. see here and other links:) >>>>> https://www.eejournal.com/article/ibm-gives-away-powerpc-goes-open-source/) >>>>> >>>>> >>>>> >>>>> >>>>> As PowerPC processors do are used in embedded devices, anybody any >>>>> idea >>>>> what this would mean for the embedded-processor market? Are >>>>> we now going to be flooded by Chinese ppc-based devboards? >>>>> And is this going to kill the risc-v? >>>> >>>> If someone takes on and starts making more power architecture >>>> processors the impact could be huge, this is by far the best >>>> architecture I have seen in my life - and I have explored most >>>> of them (and used power for decades now). Then it might make no >>>> impact at all, how many of those making decisions of such >>>> magnitude can see further than the next quarter report and can >>>> look into something other than what "everybody is doing". >>>> >>>>> >>>>> >>>>> >>>>> BTW. Does anybody have an easy-to-use overview of different >>>>> powerPC architectures out there? (especially for embedded >>>>> use) >>>>> >>>>> I've been trying to understand the different wikipedia pages >>>>> on the powerPC architectures, but it all seams to one giant >>>>> mix of names, numbers and 'books' from a dozen different >>>>> companies. >>>> >>>> The only maker of Power architecture processors is NXP (since >>>> they acquired Freescale). IBM had an embedded core some ages >>>> ago, 401 or something like that, which some other company - >>>> AMCC I think - took on but I never used any of these. >>>>
There are others that have made PPC based devices in the past. But I think NXP is the only company making microcontrollers and network processors based on PPC in any serious way. ST has (last time I looked, which was a while ago) second-source copies of a number of NXP PPC microcontrollers, but I don't think they had any of their own.
>>>>> >>>>> Cheerio! Kr. Bonne, >>>> >>>> Thanks for posting, I had missed the news so this is new to >>>> me. Good news I suppose, gives some hope that this great >>>> architecture will survive after all. >>>> >>>> Hopefully I can migrate DPS to 64 bit power sooner rather than >>>> later, I have been wanting to do it for quite some time now. >>>> Might also be some help. >>> >>> Maybe I'm not remembering it right, but I thought the PPC fell >>> out of favor because as processors got faster and more complex, >>> the PPC architecture lost it's advantages. I would seem I am not >>> remembering this correctly. >> >> The architecture did not lose its advantages, it is just as silicon >> got faster messy designs like the x86 could run fast enough for the >> general population.
The key change, I think, was the move from x86 cores that ran x86 code, to x86 processors that translated x86 instructions into an internal RISC code that is executed on a RISC core. RISC designs and load-store architectures with lots of registers are much better suited to fast execution, pipelining, OoO execution, and super-scaling than CISC ISAs. Once x86 cpus started using RISC cores internally, much of the advantage of PPC is lost in comparison. And x86 has several advantages that PPC can't get, beyond the obvious compatibility with x86 binaries. One is the x86 strong memory model - it is a good deal simpler for programmers than weaker memory model of most RISC designs, and a lot of code is written with the assumption of a strong memory model. The PPC exposes the guts of its RISC core to the programmer - and thus cannot easily change it - with x86 cpus, their RISC cores are hidden and designers can change it as they want for each new chip. They can have 37-bit wide instructions, completely re-arrange the encoding, add hundreds of registers, etc., whereas PPC designers have to stick to the ISA. Of course, PPC implementers could move in this direction too - turning PPC RISC instructions into an expanded internal RISC design for execution. I think the size of the ISA might make that harder than for the x86, and it won't solve the memory model challenge, but it could work. But they haven't had the same motivation - they haven't hit the same performance brick wall as the x86 world faced.
>> >> I don't know how far did IBM go developing it, may be they still >> do. I know only the Motorola/Freescale line, some of which I have >> used and am using. Their latest designs are 64 bits QORIQ (someone >> got away without being punished for that name) which look quite >> good really. > > There has to be some reason why they lost the war other than > marketing.
No, there doesn't. IBM have demonstrated in the past that they are capable of technical excellence combined with extraordinary screw-ups by sales, marketing, purchasing and licensing departments that don't understand the products, and don't talk to each other. The whole sad OS/2 story is an example. That doesn't mean there /aren't/ other reasons, merely that non-technical reasons can be enough.
> Apple was using the PPC and many others. So there was > clearly a market. Perhaps I didn't state things correctly. The > advantages of the PPC must not have been significant enough in larger > chips to make continued development of ever more expensive designs > worthwhile. I recall when IBM dropped out of the race. They must > have seen the handwriting on the wall.
Certainly keeping in the race was getting more and more expensive. Intel could use their server chip money to pay for it, but IBM did not have high-margin PPC customers (there Power cpu line for big iron is separate) screaming for faster cores.
> > So how does Freescale keep paying for spins on 64 bit chips? I take > it they still can hold a match to the Intel processors, rather they > are now competing with the ARMs of the world? >
They don't. No PowerPC devices come close to top Intel/AMD processors. And for the devices NXP make, the core speed is not critical. NXP make two types of PPC devices - automotive / high-reliability devices (up to about 300 MHz core speed), and networking (up to 1.5 GHz core). For the automotive devices, reliability, robustness and peripherals are key, not the core or the core speed. For the networking devices, it is the networking hardware that is key - the core is for control, not for processing. AFAIK all NXP's PPC chips are 32-bit. There is often a confusion between "Power" and "PowerPC". It doesn't help that NXP talks about their "Power" devices when they mean "PowerPC". The "Power" architecture is IBM's big iron chip, and these are big, fast, expensive, power-hungry, and full of big iron features like redundancy, hot-plugging (for memory, cores, etc.). They are made by IBM, and they run the many of the top supercomputers as well as every bank in the world. "PowerPC" was an initiative started by IBM, Apple and Motorola - taking the basic ISA from the Power world, removing all the "big" features, and making something that could be implemented in a single chip that was competitive in size, speed and cost with the x86's and 68k devices of the time, but with a scalable future.
> >>> So why did the PPC architecture stop being developed? Is this >>> still a competitive architecture in general? I'm guessing it is >>> still competitive in lower end processors for sure. How does it >>> stack up to MIPS? Isn't that one also open source? Or was that >>> open sourced only in a very limited way? >>> >> >> MIPS looks like a smaller scale power, I have not used it, just >> looked at it. No idea if it is open source. Microchip make some 32 >> bit MCU-s with MIPS, I have not heard people using them complain.
If you haven't heard them complain, you haven't heard me :-) My complaint with Microchip's MIPS microcontrollers is that they used a poor choice of core (MIPS had more appropriate ones at the time), screwed up the chip (it was to be the first microcontroller with USB 2 on the device, but it only worked at USB 1.1 speeds), crippled the compiler (optimisation was disabled unless you paid a large license fee, meaning people got the impression that the core was slow), and called it "PIC32" so that people thought MIPS cores were as brain-dead as a PIC. In my mind, Microchip and the PIC32 are the key reason we don't have a range of manufacturers making MIPS microcontrollers - as there are MIPS cores that are equivalent or better than ARM cores across the range of sizes and powers. In terms of architecture, MIPS has a different background from PowerPC (or Power before it), but there is definitely a strong similarity. MIPS is not open source, but easily licensable at different levels and for different cores. I think you can use the ISA in your own designs without a license (there are some Chinese MIPS ISA cores). You can do that with SPARC too, if anyone but Fujitsu cares.
> > Yeah, seems the open source thing is real... They seem to be saying > MIPS has some real advantages over RISC-V but they may not last... > > "While RISC-V is gaining grown[sic] the storied history of MIPS means > that the MIPS stack is far more complete, and includes things like > DSP and SIMD extensions that still don’t exist for the RISC-V > platform." > > I've read here that most MIPS designs are embedded cores in custom > ASICs. So someone already loves them. Seems the current owners of > the MIPS architecture think open sourcing the design will allow them > to sell more IP solutions. >
On 9/17/2019 11:58, David Brown wrote:
> On 17/09/2019 06:26, Rick C wrote: >> On Tuesday, September 17, 2019 at 12:11:05 AM UTC-4, Dimiter wrote: >>> On 9/17/2019 5:11, Rick C wrote: >>>> On Monday, September 16, 2019 at 4:24:40 PM UTC-4, Dimiter >>>> wrote: >>>>> On 9/16/2019 21:36, kristoff wrote: >>>>>> HI all, >>>>>> >>>>>> >>>>>> I know is this kind-of old news by now, but -as far as I see- >>>>>> this has not been discussed here: >>>>>> >>>>>> IBM is open-sourcing their PowerPC processor design. >>>>>> >>>>>> (E.g. see here and other links:) >>>>>> https://www.eejournal.com/article/ibm-gives-away-powerpc-goes-open-source/) >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> As PowerPC processors do are used in embedded devices, anybody any >>>>>> idea >>>>>> what this would mean for the embedded-processor market? Are >>>>>> we now going to be flooded by Chinese ppc-based devboards? >>>>>> And is this going to kill the risc-v? >>>>> >>>>> If someone takes on and starts making more power architecture >>>>> processors the impact could be huge, this is by far the best >>>>> architecture I have seen in my life - and I have explored most >>>>> of them (and used power for decades now). Then it might make no >>>>> impact at all, how many of those making decisions of such >>>>> magnitude can see further than the next quarter report and can >>>>> look into something other than what "everybody is doing". >>>>> >>>>>> >>>>>> >>>>>> >>>>>> BTW. Does anybody have an easy-to-use overview of different >>>>>> powerPC architectures out there? (especially for embedded >>>>>> use) >>>>>> >>>>>> I've been trying to understand the different wikipedia pages >>>>>> on the powerPC architectures, but it all seams to one giant >>>>>> mix of names, numbers and 'books' from a dozen different >>>>>> companies. >>>>> >>>>> The only maker of Power architecture processors is NXP (since >>>>> they acquired Freescale). IBM had an embedded core some ages >>>>> ago, 401 or something like that, which some other company - >>>>> AMCC I think - took on but I never used any of these. >>>>> > > There are others that have made PPC based devices in the past. But I > think NXP is the only company making microcontrollers and network > processors based on PPC in any serious way. ST has (last time I looked, > which was a while ago) second-source copies of a number of NXP PPC > microcontrollers, but I don't think they had any of their own. > >>>>>> >>>>>> Cheerio! Kr. Bonne, >>>>> >>>>> Thanks for posting, I had missed the news so this is new to >>>>> me. Good news I suppose, gives some hope that this great >>>>> architecture will survive after all. >>>>> >>>>> Hopefully I can migrate DPS to 64 bit power sooner rather than >>>>> later, I have been wanting to do it for quite some time now. >>>>> Might also be some help. >>>> >>>> Maybe I'm not remembering it right, but I thought the PPC fell >>>> out of favor because as processors got faster and more complex, >>>> the PPC architecture lost it's advantages. I would seem I am not >>>> remembering this correctly. >>> >>> The architecture did not lose its advantages, it is just as silicon >>> got faster messy designs like the x86 could run fast enough for the >>> general population. > > The key change, I think, was the move from x86 cores that ran x86 code, > to x86 processors that translated x86 instructions into an internal RISC > code that is executed on a RISC core. RISC designs and load-store > architectures with lots of registers are much better suited to fast > execution, pipelining, OoO execution, and super-scaling than CISC ISAs. > Once x86 cpus started using RISC cores internally, much of the > advantage of PPC is lost in comparison. > > And x86 has several advantages that PPC can't get, beyond the obvious > compatibility with x86 binaries. One is the x86 strong memory model - > it is a good deal simpler for programmers than weaker memory model of > most RISC designs, and a lot of code is written with the assumption of a > strong memory model. The PPC exposes the guts of its RISC core to the > programmer - and thus cannot easily change it - with x86 cpus, their > RISC cores are hidden and designers can change it as they want for each > new chip. They can have 37-bit wide instructions, completely re-arrange > the encoding, add hundreds of registers, etc., whereas PPC designers > have to stick to the ISA. > > Of course, PPC implementers could move in this direction too - turning > PPC RISC instructions into an expanded internal RISC design for > execution. I think the size of the ISA might make that harder than for > the x86, and it won't solve the memory model challenge, but it could > work. But they haven't had the same motivation - they haven't hit the > same performance brick wall as the x86 world faced.
Well emulating a processor on another - like Intel do - is nothing particularly new, I myself have emulated the 6809 on power under dps (had some code written in the mid 80-s which I still can - and do - use). However no matter how efficient your emulation is it is an emulation and has its performance cost. Under equal circumstances power can beat Intel hands down. No such comparison can be made though, if you compare this or that piece of C software you will compare a compiler to another rather than a core to another - so Intel will likely win simply because of its huge popularity, the man hours put into compilers for x86 must outdwarf these put into power compilers. So a performance comparison just cannot be done in a decent way.
> >>> >>> I don't know how far did IBM go developing it, may be they still >>> do. I know only the Motorola/Freescale line, some of which I have >>> used and am using. Their latest designs are 64 bits QORIQ (someone >>> got away without being punished for that name) which look quite >>> good really. >> >> There has to be some reason why they lost the war other than >> marketing. > > No, there doesn't. IBM have demonstrated in the past that they are > capable of technical excellence combined with extraordinary screw-ups by > sales, marketing, purchasing and licensing departments that don't > understand the products, and don't talk to each other. The whole sad > OS/2 story is an example. > > That doesn't mean there /aren't/ other reasons, merely that > non-technical reasons can be enough. > >> Apple was using the PPC and many others. So there was >> clearly a market. Perhaps I didn't state things correctly. The >> advantages of the PPC must not have been significant enough in larger >> chips to make continued development of ever more expensive designs >> worthwhile. I recall when IBM dropped out of the race. They must >> have seen the handwriting on the wall. > > Certainly keeping in the race was getting more and more expensive. > Intel could use their server chip money to pay for it, but IBM did not > have high-margin PPC customers (there Power cpu > line for big iron is > separate) screaming for faster cores.
At the point where Apple abandoned PPC and went Intel what I remember was Jobs saying Freescale (or wast it still Motorola SPS) or IBM or both could not deliver the silicon they wanted, i.e. it was a production complaint. I am not sure I buy into that, I have my conspiracy theory about what happened but well, it is just a theory of mine, I can't prove it and it might well be wrong on top of that.
> >> >> So how does Freescale keep paying for spins on 64 bit chips? I take >> it they still can hold a match to the Intel processors, rather they >> are now competing with the ARMs of the world? >> > > They don't. No PowerPC devices come close to top Intel/AMD processors. > And for the devices NXP make, the core speed is not critical. NXP make > two types of PPC devices - automotive / high-reliability devices (up to > about 300 MHz core speed), and networking (up to 1.5 GHz core). For the > automotive devices, reliability, robustness and peripherals are key, not > the core or the core speed. For the networking devices, it is the > networking hardware that is key - the core is for control, not for > processing. AFAIK all NXP's PPC chips are 32-bit.
Oh no, they have 64 bits for years now. Just check the website, they have up to 8 physical cores and 16 logical ones (or was it 4/8), just look for QORIQ power. Really powerful beasts they are, GHz range, 750 MHz clocked DDR4 etc., that on a SoC.
> > > There is often a confusion between "Power" and "PowerPC". It doesn't > help that NXP talks about their "Power" devices when they mean "PowerPC" > > The "Power" architecture is IBM's big iron chip, and these are big, > fast, expensive, power-hungry, and full of big iron features like > redundancy, hot-plugging (for memory, cores, etc.). They are made by > IBM, and they run the many of the top supercomputers as well as every > bank in the world. > > "PowerPC" was an initiative started by IBM, Apple and Motorola - taking > the basic ISA from the Power world, removing all the "big" features, and > making something that could be implemented in a single chip that was > competitive in size, speed and cost with the x86's and 68k devices of > the time, but with a scalable future.
PowerPC (PPC) was dropped some 10 years ago as a name, it is called "Power Architecure" nowadays. Not to be confused with IBM's Power from the 80s, which is sort of the same but not quite, this is where the architecture originated (the guy who did it has been really good). Of course people use PPC and power interchangeably nowadays so unless you are intimate with what is on offer it can be a source of confusion. Dimiter ====================================================== Dimiter Popoff, TGI http://www.tgi-sci.com ====================================================== http://www.flickr.com/photos/didi_tgi/
Hi Rick, all,

First, thanks to all for replying and taking up this thread. This is 
very interesting.


On 17/09/19 04:11, Rick C wrote:
> How does it stack up to MIPS? Isn't that one also open source? Or was that open sourced only in a very limited way?
I wasn't aware that MIPS ISA has been open-sourced. According wikipedia, the descision to open-source was taken in 2018, to be executed in 2019. https://www.mipsopen.com/ Note that they just call it "open" and "open use", not open-source and -as far as I see it- it is not open source. E.g. the license agreement states that the technology (including the ISA) is still subject to US export-control, which makes the license incompatible with any open-source license. It looks more like 'freeware' then 'open source'. Note that their website also mentions two cores: the microAptiv UP and UC cores. This makes them much less open then (say) risc-v or the opensparc licenses. Kristoff
David,


On 17/09/19 10:13, David Brown wrote:
>> I know is this kind-of old news by now, but -as far as I see- this has >> not been discussed here:
>> IBM is open-sourcing their PowerPC processor design. > No, they are not (as far as I understand the situation). The linked > article seems a bit mixed up as to what they are giving away (they are > mixed up about RISC-V too).
That's very correct. The information at this point is very sparse and unclear. It looks like they are currently open-sourcing the ISA, some additional interfaces specs and a softcore implementation of the the POWER ISA. I guess we need to wait and see exactly what the license of all these goodies will say. BTW. For who is interested, there is also an open-source implementation of the 64bit ISA called the "microwatt": https://github.com/antonblanchard/microwatt I do not know what version of the ISA is implemented, but -if this information can help- this project seams to use the POWER8 toolchain to (cross-)compile micropython. Does this say anything about what version of the ISA is implemented.
> I'm guessing answers to all these points are to be found with a bit of > research on the Linux Foundation or IBM's websites, but they need > considered before it is clear what IBM have actually done here.
I agree. Let's wait and see.
>> As PowerPC processors do are used in embedded devices, anybody any idea >> what this would mean for the embedded-processor market? > > Mostly nothing, I think. > > PPC cores are used in a few specific embedded markets - primarily the > automotive industry, and other tough industrial uses. They used to be > popular in networking systems (along with MIPS), but ARM is taking over > that niche.
I know. I remember seeing it on the boot screen of Cisco routers.
>> BTW. >> Does anybody have an easy-to-use overview of different powerPC >> architectures out there? (especially for embedded use) > I'd be surprised if such a thing exists. There are /many/ PPC variations.
Can you explain the difference between the "books" and the Power ISA versions, as found on the Wikipedia page here: https://en.wikipedia.org/wiki/Power_ISA Also, what is the link between a particular core implementation and the books / Isa. E.g. Say you would like to implement a very low-end ppc core for embedded applications. Do you need to implement the full ISA with all its features or are certain parts of the ISA optional? (e.g. Is it mandatory to add a FPU to the core?) Thanks! Kristoff