re: compile and run 32bit programs on aarch64eb

[matthew green <mrg%eterna23.net@localhost>]

the original arm64 port of netbsd included 32-bit eabi compat support
in the base distro, same as sparc64 has sparc, or amd64 has i386, etc.

however, this feature relies up on the compiler supporting it, and
while the original netbsd/arm64 compiler was clang, and thus supported
many targets, the GCC port of arm64 is a brand new target from the arm32
target, and it's not clear the aarch32 support in aarch64-gcc is sufficient
to try to support this feature (i haven't managed to make it work but i've
also not finished attempts.  would be great if someone else figured this
out.)

alternatively, we need a way to support multiple toolchains in a single
build (eg, have tools/Makefile visit several subdirs multiple times if
there is al ist of targets), and then the compat build could use the other
actual compiler to build the 32 bit sets again.

it would be great if someone figured this out for me.  :-)


Martin Husemann writes:
> On Wed, Nov 26, 2025 at 04:26:30PM +0300, Valery Ushakov wrote:
> > sligtly different set of atomic primitives is provided by the compat
> > libc (this might or might not be a bug, I couldn't get an answer from
> > people in the know).
>
> I think this is because on sparc64 we know the hardware is at least sun4u,
> so we can assume all sparcv9 instructions are available, while the regular
> sparc libs are build for sparcv7 (with optional overlays for sparcv8).

yes - this is on purpose, and designed to run 32-bit on v9 CPU.



.mrg.