Re: git: 96acaa960023 - main - compat32: provide a type and a macro for (u)int64_t handling on non-x86 arches

On 20 Jan 2026, at 14:42, Konstantin Belousov <kib@FreeBSD.org> wrote:
> 
> The branch main has been updated by kib:
> 
> URL: https://cgit.FreeBSD.org/src/commit/?id=96acaa960023c20e852e04e7cc5c6a5faca36c67
> 
> commit 96acaa960023c20e852e04e7cc5c6a5faca36c67
> Author:     Konstantin Belousov <kib@FreeBSD.org>
> AuthorDate: 2026-01-12 04:45:36 +0000
> Commit:     Konstantin Belousov <kib@FreeBSD.org>
> CommitDate: 2026-01-20 14:42:35 +0000
> 
>    compat32: provide a type and a macro for (u)int64_t handling on non-x86 arches
> 
>    uint64_t is 4-byte aligned on i386, but is 8-bytes aligned on all other
>    32bit arches FreeBSD supports.  Provide the freebsd32_uint64_t type and
>    the FU64_CP() macro, which are intended to be used where 32bit ABI uses
>    (u)int64_t type, and do proper layout and copying for the aggregate type.
> 
>    Reviewed by:    des, emaste
>    Sponsored by:   The FreeBSD Foundation
>    MFC after:      1 week
>    Differential revision:  https://reviews.freebsd.org/D54663
> ---
> sys/compat/freebsd32/freebsd32.h | 11 ++++++++++-
> sys/sys/abi_compat.h             |  8 ++++++++
> 2 files changed, 18 insertions(+), 1 deletion(-)
> 
> diff --git a/sys/compat/freebsd32/freebsd32.h b/sys/compat/freebsd32/freebsd32.h
> index 9d724c93fee7..7324f9adf70c 100644
> --- a/sys/compat/freebsd32/freebsd32.h
> +++ b/sys/compat/freebsd32/freebsd32.h
> @@ -36,8 +36,17 @@
> #include <sys/_ffcounter.h>
> 
> /*
> - * i386 is the only arch with a 32-bit time_t
> + * i386 is the only arch with a 32-bit time_t.
> + * Also it is the only arch with (u)int64_t having 4-bytes alignment.
>  */
> +typedef struct {
> +#ifdef __amd64__
> + uint32_t val[2];
> +#else
> + uint64_t val;
> +#endif
> +} freebsd32_uint64_t;

Any reason not to use:

  typedef uint64_t freebsd32_uint64_t __aligned(4);

on amd64 (and normal typedef elsewhere)? Then you can just use the
normal CP. See for example https://godbolt.org/z/svseWv7xo.

Jessica