Vaguely describe the frame-parameter. Beautify.

share/man/man9/hardclock.9

@@ -1,4 +1,4 @@
-.\"	$NetBSD: hardclock.9,v 1.2 2008/04/30 13:10:58 martin Exp $
+.\"	$NetBSD: hardclock.9,v 1.3 2010/03/25 15:17:38 jruoho Exp $
 .\"
 .\" Copyright (c) 2001 The NetBSD Foundation, Inc.
 .\" All rights reserved.
@@ -27,7 +27,7 @@
 .\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 .\" POSSIBILITY OF SUCH DAMAGE.
 .\"
-.Dd September 5, 2001
+.Dd March 25, 2010
 .Dt HARDCLOCK 9
 .Os
 .Sh NAME
@@ -35,15 +35,23 @@
 .Nd real-time timer
 .Sh SYNOPSIS
 .Ft void
-.Fn hardclock "struct clockframe *"
+.Fn hardclock "struct clockframe *frame"
 .Sh DESCRIPTION
 The
 .Fn hardclock
-function gets called
+function is called
 .Xr hz 9
 times per second.
-It performs different tasks:
-.Bl -bullet -compact
+It implements the real-time system clock.
+The argument
+.Va frame
+is an opaque,
+machine-dependent structure that encapsulates the previous machine state.
+.Pp
+The
+.Fn hardclock
+performs different tasks such as:
+.Bl -bullet -offset indent
 .It
 Run the current process's virtual and profile time (decrease the
 corresponding timers, if they are activated, and generate