Re: [PATCH] rust: Add PowerPC support

[Alice Ryhl <aliceryhl@google.com>]

On Wed, Feb 04, 2026 at 12:36:38PM +0000, Gary Guo wrote:
> On Wed Feb 4, 2026 at 10:41 AM GMT, Alice Ryhl wrote:
> > On Wed, Feb 04, 2026 at 04:05:04AM +0100, Link Mauve wrote:
> >> For now only Big Endian 32-bit PowerPC is supported, as that is the only
> >> hardware I have.  This has been tested on the Nintendo Wii so far, but I
> >> plan on also using it on the GameCube, Wii U and Apple G4.
> >
> > Super cool!
> >
> >> These changes aren’t the only ones required to get the kernel to compile
> >> and link on PowerPC, libcore will also have to be changed to not use
> >> integer division to format u64, u128 and core::time::Duration, otherwise
> >> __udivdi3() and __umoddi3() will have to be added.  I have tested this
> >> change by replacing the three implementations with unimplemented!() and
> >> it linked just fine.
> >
> > Uh oh this seems tricky. How is this not a problem on arm32 too?
> >
> > Perhaps we should just be providing __udivdi3() and __umoddi3() in
> > general?
> 
> I think there is some concern that if this is provided, then C side that uses
> the divide operator instead of dividing function doesn't get linker error
> anymore.
> 
> However, a proper way is to do this via the hooks that we already have in
> `compiler_builtins.rs`.
> 
> This can either be replace these with panics or actual implementation, but for
> libcore.o only.

Is there any reason to not make it Rust-only but for all Rust code?
Making the / operator work seems like it would be a good idea.

Alice