.\"	$NetBSD: compat_netbsd32.8,v 1.9 2011/09/13 09:16:15 wiz Exp $
.\"
.\" Copyright (c) 2001 Matthew R. Green
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.Dd March 11, 2006
.Dt COMPAT_NETBSD32 8
.Os
.Sh NAME
.Nm compat_netbsd32
.Nd setup procedure for 32-bit compatibility on 64-bit platforms
.Sh DESCRIPTION
The
.Nm
module allows
.Nx Ns Tn /sparc64
to run
.Nx Ns Tn /sparc
executables, and
.Nx Ns Tn /amd64
to run
.Nx Ns Tn /i386
executables.
.Pp
To use
.Nm ,
one must either have
.Dv COMPAT_NETBSD32
and
.Dv EXEC_ELF32
in the kernel, or load the compat_netbsd32 and exec_netbsd32 kernel
modules.
.Pp
Static executables typically need no additional setup.
Dynamic binaries require the dynamic linker plus shared libraries.
Most of these files will need to be placed under
.Pa /emul/netbsd32 .
.Pp
The easiest method of installing support for these is via the
.Pa emulators/netbsd32_compat14 ,
.Pa emulators/netbsd32_compat15 ,
and
.Pa emulators/netbsd32_compat16
packages, provided in the
.Nx
packages collection.
These install 32-bit a.out and ELF compatibility libraries,
respectively.
The details of what is actually necessary for correct operation
are given below.
This obviously is handled by the emulator packages.
.Pp
For a.out compatibility,
.Pa /usr/libexec/ld.so
from a 32-bit distribution is required to exist as
.Pa /emul/netbsd32/usr/libexec/ld.so .
For 32-bit ELF compatibility,
.Pa /usr/libexec/ld.elf_so
needs to be in
.Pa /emul/netbsd32/usr/libexec/ld.elf_so .
.Pp
The shared libraries for a.out binaries do not live under the
.Pa /emul/netbsd32
directory, but under the
.Pa /emul/aout
directory, where the a.out dynamic linker will find them.
.Sh BUGS
A list of things which fail to work in compatibility mode should
be here.
.Pp
IPC is not well supported.
.Pp
.Xr sysctl 3
is not well supported.