Intel Wants to KILL 32-bit Mode in its CPUs - X86-S Explained

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#garyexplains

[Winnetou]

Fun fact: because of the 16 bit modes, you can still boot into MS-DOS and/or FreeDOS on any modern x86 CPU. Well, if I'm not mistaken you still need to have legacy BIOS boot, the MBR kind and the keyboard has to be PS/2 or emulated, not stricly on USB. At least for MS-DOS. FreeDOS I think has a few extra compatibility features.

[turosianarcher]

One interesting point that Gary didn't make is the reason that AMD was the one to come out with 64-bit x86 extensions instead of Intel, and that this is not the first time Intel tried to leave compatibility modes (and maybe x86 clone companies?) behind. At the time, Intel and HP were pushing their VLIW (corrected thanks to James Duncan below) architecture called Itanium as a 64-bit solution and letting their x86 lineup remain at 32-bit for the consumer market, and Microsoft created a version of windows to support the new Itanium 64 bit architecture for Intel & HP. Around the same time, AMD (who had an x86 license but NOT an Itanium license) had no choice but to continue to develop x86 or face irrelevancy. Thus, the AMD-64 architecture was born, backwards compatibility was preserved, and Microsoft built the 64-bit version of Windows for this x86 64-bit standard. When the Itanium stagnated, and AMD64 gained traction in the market as a compatible alternative, Intel had to do something, and was rumored to be coming up with their own extensions to x86. To add insult to injury (if I remember correctly) after the costs of building an Itanium version, Microsoft was reluctant to build *another* x86-64 version for Intel's proposed 64 bit x86 competitor, forcing Intel to make their processors compatible with the AMD-64 instructions for 64-bit x86 moving forwards.

I think that removing backwards compatibility mode, so long as the ability to use older programs in emulation was sufficient, probably will be good for the average consumer. If it isn't though, be sure that AMD will be there again to capitalize on what Intel leaves on the table. If it makes sense, great...we all get better faster machines. If it doesn't make sense, someone will be there to "retain compatibility because people want it" and gain market share because of it. Either way, it'll work out.

[suki]

Fun fact: I worked in a small software house just before the millenium. They used clipper as software for their video customers. We were in panic, because at this time the motherboard producers wanted to switch to modern standards with only USB and no PS2 or serial connection. We used normal desktop computers as billing points.

[jameshogge]

Lots of people are talking about compatibility with older operating systems but that is already a lost battle:
With the likes of UEFI, GPT disks and secure boot, it is already impossible to boot the really old OSes (like DOS) in 16bit mode. With the management engine on modern CPUs, it is also often impossible to flash custom firmware and get around this.

At this point, the legacy boot modes are already mostly useless. Management engine was the thing to complain about as that actually prevents you from running unsigned firmware

[mcguru]

Ahoy, thanks for the video. Remember, this is bleeding edge stuff. In the Real World (R) such as banking and industry 16 bits isn't even dead as some of it still runs on that (especially industrial machines). Before I retired in 2011 I was still servicing 32 bit Warpserver computers, mostly at banks, investment firms and retail stores. I suspect I'll be fertilizer before this comes to full fruition. Cheers, daveyb

[peteblazar]

I think main reason are "soon" expiring patents for start "edition" x86_64, new patents for x86_64-S will block enter in the market for other players. All legacy instruction are probably for decades executed by micro-code.

[jeffnew]

Just considering that BIOSes and UEFI firmware will have to change as will all hypervisors which will offer virtualization of and on these new processors. It's going to be a long, long transition.

[pychang]

This probably won't affect most end users, but it's kind a big news in the computer history.
Btw I didn't know that cpu nowadays still boot into 16-bit mode first and then transit to 64-bit. Great content as always!😄

[billybob]

As long as I can still play 16bit games from that awkward period where it's too new for DOS and too old for 32-bit windows, I'm happy.

[Crossfire]

I am all for the x86-S mode implementation!
Apple dropped the 16-bit & 32-bit modes years ago!

[olovik]

interesting how much die space this will save for x86 CPUs? how much energy is wasted? Intel wants to catch up with others and going to redesign their architecture.

[GuruEvi]

The question is really whether it makes sense to switch then to X86-S vs just going straight for ARM. The only reason Intel is still big is because of Windows with its own 16-and-32-bit mode software still commonly in use (eg. Excel) which has things like OLE and DDE from Windows 3.0 that many, many software sold today still haven't changed (unlike Mac, nobody is forcing them to modernize).

[Akck]

Gary, what are the benefits of a 64 bit only cpu? Would it allow them to save on die size by removing some transistors? And with modern SSD based systems booting pretty fast, would this make a noticeable difference in boot times?

[combat.wombat]

Did Intel talk about how much die space might be saved (if any) from cutting out the older modes?

[shaurz]

Unfortunately they are still keeping the GDT, LDT, IDT and segment registers since they can't get rid of that without breaking existing operating systems.

[altmindo]

i think x86-s its a good idea without a hidden business agenda. would ease the design of x86-64 cpus from scratch (not that there are a lot of new ground-up designs now)

[shaurz]

It's a step in the right direction but they should really bite the bullet and introduce a new encoding, drop the segment registers, legacy floating point instructions and registers, legacy descriptor tables, obsolete instructions, etc. ARM did this with ARM64 - which is essentially a completely new instruction set compared to 32-bit ARM.

[felicytatomaszewska]

06:37 I guess you wanted to say you can't get 32-bit version of Win-11.

[iProductions]

I am quite sure that technically UEFI is only 32 / 64 bits at boot.. however a lot of UEFIs also include or a built upon traditional BIOS'.. partly for compatibility and partly because you can easily get hold of these from certain companies (eg AMI) rather than to have to make one from scratch.. Also I'm quite sure you can write a boot loader for a UEFI that supports 16-bit.. but initially it will have to execute in 32-bit mode.. On another note I think that the discontinued Itanium range by Intel were 64bit only. Also just a simple mistake @6:30 you state that "you can't get a 64-bit version of windows 11" 😛!

[MonochromeWench]

This has been a long time coming with Intel already getting rid of UEFI CSM on their boards. No CSM means no MBR booting, so really only modern 64bit Operating system can be used.