6 ms·

I don't hate X86, but I hope to god it finally goes, and I know I won't miss it.

by mhh__ 6y ago

deleted 6y ago
[deleted]
raptorxp 6y ago
x86-64 isn't going anywhere. Not in the next decade or two anyway.
- danielheath 6y ago
  I don't know about "gone", but "reduced to legacy support roles within 10 years" seems like a pretty uncontroversial statement.
  - fogihujy 6y ago
    I'd be surprised if that turned out to be true, but I truly hope that I'm wrong and you're right. :D
    - danielheath 6y ago
      The story so far: ARM chips last longer on battery, and every high volume laptop manufacturer had an ARM model. Every smartphone is already arm. ARM already has mainline support from every major OS vendor. Every videogame engine builds for ARM targets. In AWS, Graviton2 instances are 40% cheaper for cpu bound workloads vs x86. Next time our reserved instances expire we will switch.
      - fogihujy 6y ago
        Meanwhile, people are clinging to decade-old Thinkpads like they were made of gold. Most laptops and pretty much all desktops are x86-64, as are both major home consoles. Sure, ARM is dominant on mobile, and it's definitely going to grab a share of the laptop market now that Apple is going that route. Eventually we might also see ARM based desktop computers again, but having them grab the majority of sales will take time. I'm sure it'll happen - just not within a decade.
- seniorivn 6y ago
  if for some reason x86-64 will become incompatible with novel highly advantageous architectural decisions of competitors, AMD and Intel will ditch it, and make cpus with different/new architectures
  - klelatti 6y ago
    Certainly for Intel I think that it's unlikely that they will switch and maintain anything like their market position in CPUs. - There is too much attachment to x86 and too much pain associated with historical attempts to move to other architectures - obviously Itanium being the most recent. - Moving from x86 means losing the architecture duopoly. - By the time x86 is clearly failing in the market competitors will have gained a major foothold in the market. - The lead in time to switch is too long to reverse the pattern of decline. I strongly suspect that it's already too late given the pattern we're seeing with M1 and AWS and Graviton.
- bruce343434 6y ago
  Source: trust me bro
pjc50 6y ago
Indeed - misaligned instructions don't work on ARM, the instruction pointer has to be word-aligned.
- classichasclass 6y ago
  Most RISC and RISC-derived instruction sets are this way. Power ISA also faults if the PC isn't aligned to 32 bits. ARM Thumb encoding makes this a hair more complex, but certainly less than x86.
- q-big 6y ago
  T32 has 16 and 32 bit instructions and is not self-synchronizing. Thus, the problem is much less severe on ARM (T32), but not non-existent.
Joker_vD 6y ago
You know, I've spent the past two weeks tinkering with a toy x86_64 bootloader/kernel, and I think that x86 as an ISA is okay. Not great, but okay. Yes, 16-bit addressing modes are restrictive, the encoding hack that enables addressing of r8-r15 in the long mode is probably against one of Geneva conventions, the constant proliferation of control registers is vexing, and CPUID will one day probably be able to dump a full 10-volume PDF of Software Developer's Manual into the provided memory... but still, it's kinda okay. But what's absolutely terrible is the interface between the CPU and everything else attached to the mainboard (and with the mainboard itself, for that matter). The interrupt handling somehow gets worse when moving from PIC to APIC, ACPI is nauseating, I/O ports are insanely opaque, and the default memory-mapped devices are organized in such a way that there are irreparable wholes in the physical address space that you can't use anyway. Having physical RAM start, say, at address 0x800000000000 and everything below it be MMIO would be pretty convenient, but it can't be arranged for legacy reasons. The legacy boot sequence is appalling. UEFI is marginally better, but is itself an impressive bag of worms. Holy fatcats. I hope RISC-V will have saner peripherals, but kinda afraid that it won't either.
- userbinator 6y ago
  the constant proliferation of control registers is vexing You may want to look at the AArch64 "system registers" space... or the instruction encoding, for that matter. I think 32-bit x86 made the most sense and was well thought-out, but the 64-bit version was definitely not extended very well.
  - Joker_vD 6y ago
    Yep. It's le bon ton to frown at the x86's baroqueness, but other ISAs had their share of bizarre ideas as well: e.g. MIPS had no interlocks until MIPS-II, so every instruction had a delay slot. I personally liked the SIB byte from x86-32, it's a neat way to repurpose an ACU into basically another ALU.
- bogomipz 6y ago
  >"the encoding hack that enables addressing of r8-r15 in the long mode is probably against one of Geneva conventions ..." Might you or anyone else have any links or literature on what this hack is or how it works? >"the constant proliferation of control registers is vexing ..." I'm guessing this isn't referring to control registers proliferating on different of generations of CPUs at the discussion is about the ISA. Could you elaborate on how exactly they've proliferated?

I don't hate X86, but I hope to god it finally goes, and I know I won't miss it.

by mhh__ 6y ago

I don't hate X86, but I hope to god it finally goes, and I know I won't miss it.

deleted 6y ago

[deleted]

raptorxp 6y ago

x86-64 isn't going anywhere. Not in the next decade or two anyway.

danielheath 6y ago
I don't know about "gone", but "reduced to legacy support roles within 10 years" seems like a pretty uncontroversial statement.
- fogihujy 6y ago
  I'd be surprised if that turned out to be true, but I truly hope that I'm wrong and you're right. :D
  - danielheath 6y ago
    The story so far: ARM chips last longer on battery, and every high volume laptop manufacturer had an ARM model. Every smartphone is already arm. ARM already has mainline support from every major OS vendor. Every videogame engine builds for ARM targets. In AWS, Graviton2 instances are 40% cheaper for cpu bound workloads vs x86. Next time our reserved instances expire we will switch.
    - fogihujy 6y ago
      Meanwhile, people are clinging to decade-old Thinkpads like they were made of gold. Most laptops and pretty much all desktops are x86-64, as are both major home consoles. Sure, ARM is dominant on mobile, and it's definitely going to grab a share of the laptop market now that Apple is going that route. Eventually we might also see ARM based desktop computers again, but having them grab the majority of sales will take time. I'm sure it'll happen - just not within a decade.
seniorivn 6y ago
if for some reason x86-64 will become incompatible with novel highly advantageous architectural decisions of competitors, AMD and Intel will ditch it, and make cpus with different/new architectures
- klelatti 6y ago
  Certainly for Intel I think that it's unlikely that they will switch and maintain anything like their market position in CPUs. - There is too much attachment to x86 and too much pain associated with historical attempts to move to other architectures - obviously Itanium being the most recent. - Moving from x86 means losing the architecture duopoly. - By the time x86 is clearly failing in the market competitors will have gained a major foothold in the market. - The lead in time to switch is too long to reverse the pattern of decline. I strongly suspect that it's already too late given the pattern we're seeing with M1 and AWS and Graviton.
bruce343434 6y ago
Source: trust me bro

pjc50 6y ago

Indeed - misaligned instructions don't work on ARM, the instruction pointer has to be word-aligned.

classichasclass 6y ago
Most RISC and RISC-derived instruction sets are this way. Power ISA also faults if the PC isn't aligned to 32 bits. ARM Thumb encoding makes this a hair more complex, but certainly less than x86.
q-big 6y ago
T32 has 16 and 32 bit instructions and is not self-synchronizing. Thus, the problem is much less severe on ARM (T32), but not non-existent.

Joker_vD 6y ago

You know, I've spent the past two weeks tinkering with a toy x86_64 bootloader/kernel, and I think that x86 as an ISA is okay. Not great, but okay. Yes, 16-bit addressing modes are restrictive, the encoding hack that enables addressing of r8-r15 in the long mode is probably against one of Geneva conventions, the constant proliferation of control registers is vexing, and CPUID will one day probably be able to dump a full 10-volume PDF of Software Developer's Manual into the provided memory... but still, it's kinda okay. But what's absolutely terrible is the interface between the CPU and everything else attached to the mainboard (and with the mainboard itself, for that matter). The interrupt handling somehow gets worse when moving from PIC to APIC, ACPI is nauseating, I/O ports are insanely opaque, and the default memory-mapped devices are organized in such a way that there are irreparable wholes in the physical address space that you can't use anyway. Having physical RAM start, say, at address 0x800000000000 and everything below it be MMIO would be pretty convenient, but it can't be arranged for legacy reasons. The legacy boot sequence is appalling. UEFI is marginally better, but is itself an impressive bag of worms. Holy fatcats. I hope RISC-V will have saner peripherals, but kinda afraid that it won't either.

userbinator 6y ago
the constant proliferation of control registers is vexing You may want to look at the AArch64 "system registers" space... or the instruction encoding, for that matter. I think 32-bit x86 made the most sense and was well thought-out, but the 64-bit version was definitely not extended very well.
- Joker_vD 6y ago
  Yep. It's le bon ton to frown at the x86's baroqueness, but other ISAs had their share of bizarre ideas as well: e.g. MIPS had no interlocks until MIPS-II, so every instruction had a delay slot. I personally liked the SIB byte from x86-32, it's a neat way to repurpose an ACU into basically another ALU.
bogomipz 6y ago
>"the encoding hack that enables addressing of r8-r15 in the long mode is probably against one of Geneva conventions ..." Might you or anyone else have any links or literature on what this hack is or how it works? >"the constant proliferation of control registers is vexing ..." I'm guessing this isn't referring to control registers proliferating on different of generations of CPUs at the discussion is about the ISA. Could you elaborate on how exactly they've proliferated?