diff --git a/usr.sbin/genassym/Makefile b/usr.sbin/genassym/Makefile
index 863c13cd70ee..36420acdcd27 100644
--- a/usr.sbin/genassym/Makefile
+++ b/usr.sbin/genassym/Makefile
@@ -1,6 +1,6 @@
-#	$NetBSD: Makefile,v 1.1 2005/05/31 03:48:43 christos Exp $
+#	$NetBSD: Makefile,v 1.2 2005/05/31 11:35:54 christos Exp $
 
-NOMAN=		yes
+MAN=		genassym.8
 SCRIPTS=	genassym.sh
 
 .include <bsd.prog.mk>
diff --git a/usr.sbin/genassym/genassym.8 b/usr.sbin/genassym/genassym.8
new file mode 100644
index 000000000000..b011a1d65e90
--- /dev/null
+++ b/usr.sbin/genassym/genassym.8
@@ -0,0 +1,92 @@
+.\"	$NetBSD: genassym.8,v 1.1 2005/05/31 11:35:54 christos Exp $
+.\"
+.\" Copyright (c) 1997 Matthias Pfaller.
+.\" All rights reserved.
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\"    notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\"    notice, this list of conditions and the following disclaimer in the
+.\"    documentation and/or other materials provided with the distribution.
+.\" 3. All advertising materials mentioning features or use of this software
+.\"    must display the following acknowledgement:
+.\"	  This product includes software developed by Matthias Pfaller.
+.\" 4. The name of the author may not be used to endorse or promote products
+.\"    derived from this software without specific prior written permission
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+.\"
+.Dd May 31, 2005
+.Dt GENASSYM 8
+.Os
+.Sh NAME
+.Nm genassym
+.Nd emit an assym.h file
+.Sh SYNOPSIS
+.Nm genassym
+.Op Fl c
+.Op Fl f
+.Ar C compiler invocation
+.Sh DESCRIPTION
+.Nm
+is a shell script normally used during the kernel build process to
+create an assym.h file.
+This file defines a number of cpp constants derived from the configuration
+information
+.Nm
+reads from stdin. The generated file is used by kernel sources
+written in assembler to gain access to information (e.g. structure
+offsets and sizes) normally only known to the C compiler.
+Arguments to
+.Nm
+are usually of the form
+.Ar ${CC} ${CFLAGS} ${CPPFLAGS}
+where
+.Ar ${CC}
+is the C compiler used to compile the kernel, while
+.Ar ${CFLAGS}
+and
+.Ar ${CPPFLAGS}
+are flag arguments to the C compiler. The script creates a C source file
+from its input. Then the C compiler is called according to the script's
+arguments to compile this file. Normally
+.Nm
+instructs the C compiler to create an assembler source from the constructed
+C source. The resulting file is then processed to extract the information
+needed to create the assym.h file. The
+.Fl c
+flag instructs
+.Nm
+to create slightly different code, generate an executable from this code
+and run it. In both cases the assym.h file is written to stdout.
+The
+.Fl f
+flag instructs
+.Nm
+to create forth code.
+.Sh DIAGNOSTICS
+Either self-explanatory, or generated by one of the programs
+called from the script.
+.Sh SEE ALSO
+.Xr genassym.cf 5
+.Sh HISTORY
+The
+.Nm
+command appeared in
+.Nx 1.3
+as genassym.sh in
+.Pa /sys/kern .
+It became a userland utility in
+.Nx 4.0 .