Not to be confused with Is my OS 32-bit or 64-bit.

This one is very simple, tell me whether or not my CPU supports 64-bit instructions. If my CPU supports 32-bit instructions, print '32', if my CPU supports 64 bit instructions, print '64', if my processor naitively supports other lengths of instructions, print 'other'.

Your program must run on both 32 and 64-bit instruction modes, and if interpreted run properly on both 32 and 64-bit interpreters.

Test cases:

Arch: x86, i386, i686, RiscV32
Output: '32'

Arch: x86-64, x64, x86_64, RiscV64
Output: '3264'

Arch: R700
Output '32other'

The usual rules apply.

Best of luck!

  • 6
    \$\begingroup\$ I don't think this should be tagged as a decision-problem, since there are more than 2 possible answers. (Although both the title and the 1st sentence of the description suggest that it's a "yes/no" kind of problem.) \$\endgroup\$
    – Arnauld
    Commented Sep 10, 2020 at 14:28
  • 1
    \$\begingroup\$ @Arnauld A decision between more than 2 options is still a decision. \$\endgroup\$
    – tuskiomi
    Commented Sep 10, 2020 at 14:38
  • 8
    \$\begingroup\$ Sure, but it's not a decision-problem anymore as defined in computability theory. \$\endgroup\$
    – Arnauld
    Commented Sep 10, 2020 at 14:46
  • 1
    \$\begingroup\$ Is that the full list of inputs we're expected to handle and is there any flexibility in the output? \$\endgroup\$
    – Shaggy
    Commented Sep 11, 2020 at 0:50
  • 1
    \$\begingroup\$ I don't think any of the existing answers ever print other, maybe you should consider removing that requirement. \$\endgroup\$ Commented Sep 11, 2020 at 11:56

2 Answers 2


Bash + coreutils, 33 25 bytes

lscpu|grep -Po '..(?=-b)'

Don't try it online! Won't work because the TIO sandbox doesn't support lscpu. Edit: Saved 8 bytes thanks to @DigitalTrauma.

  • \$\begingroup\$ it even works on RISC-V Debian! \$\endgroup\$
    – tuskiomi
    Commented Sep 10, 2020 at 15:10
  • 1
    \$\begingroup\$ That's Linux specific, isn't? lscpu isn't present on all OSses, not even all Unices. \$\endgroup\$
    – Abigail
    Commented Sep 10, 2020 at 15:20
  • \$\begingroup\$ @Abigail I'd still say it's legal, as it's interpreted, and it runs properly for 32 or 64 bit linux \$\endgroup\$
    – tuskiomi
    Commented Sep 10, 2020 at 15:29
  • 2
    \$\begingroup\$ @tuskiomi I'm pretty sure what Abigail meant was that the title of the post isn't correct. I'd guess it should say something like Bash + coreutils on Linux, at the very least. I'm not sure if there's a better name or way to identify what contains this command. \$\endgroup\$ Commented Sep 10, 2020 at 16:30
  • \$\begingroup\$ Use grep's PCRE flag to obviate the need for sed: lscpu|grep -Po '..(?=-bit)' \$\endgroup\$ Commented Sep 10, 2020 at 16:49

Rust, 45 bytes

||if std::usize::MAX>4294967295{3264}else{32}

Try it online! (Cross compile for 32-bit locally by installing a toolchain for i686. For example: stable-i686-pc-windows-msvc)

Can't really test this on any architectures that support "other" lengths of instructions, but this can be used to check for 32-bit or 64-bit architectures. This is shorter than the built-in way using cfg!(target_pointer_width="64").

  • \$\begingroup\$ Does not work. This is 3264 when compiled as 32-bit on a 64-bit processor. \$\endgroup\$ Commented Sep 15, 2020 at 13:34
  • \$\begingroup\$ @user253751 Can you share what steps you took to compile for 32-bit? The documentation for usize states that the actual size of usize is based on the pointer size. It was working for me fine when I targeted i686, but I'm not completely sure how to target 32-bit aside from that. \$\endgroup\$
    – TehPers
    Commented Sep 15, 2020 at 16:48
  • \$\begingroup\$ Oops, I meant to say the correct output would be 3264 and this outputs 32. I did not run it, but it is obvious by inspection... \$\endgroup\$ Commented Sep 15, 2020 at 16:56
  • \$\begingroup\$ @tuskiomi Can you clarify what should happen if your code is cross-compiled? Currently my solution works if you target the architecture you're on, but assumes the target architecture if you cross-compile. \$\endgroup\$
    – TehPers
    Commented Sep 15, 2020 at 17:22
  • \$\begingroup\$ it seemed pretty clear to me. "If my CPU supports 64 bit instructions". NOT "If the program contains 64 bit instructions" \$\endgroup\$ Commented Sep 15, 2020 at 18:24

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