updates to seconds(9)

Reference: /n/atom/patch/applied/seconds9
Date: Sun Jun  8 12:28:23 CES 2014
Signed-off-by: quanstro@quanstro.net

--- /sys/man/9/seconds	Sun Jun  8 12:28:19 2014
+++ /sys/man/9/seconds	Sun Jun  8 12:28:19 2014
@@ -1,6 +1,6 @@
 .TH SECONDS 9
 .SH NAME
-seconds, ticks, fastticks, HZ, MS2HZ, MS2TK, TK2MS, TK2SEC \- kernel times and time conversions
+seconds, ticks, tickscmp, ms2tk, tk2ms, fastticks, HZ, MS2HZ, MS2TK, TK2MS, TK2SEC \- kernel times and time conversions
 .SH SYNOPSIS
 .ta \w'\fL#define 'u
 .B
@@ -10,8 +10,19 @@
 m->ticks
 .br
 MACHP(0)->ticks
+.br
+sys->ticks	(nix only)
 .PP
 .B
+long	tickscmp(ulong, ulong)
+.br
+.B
+ulong	tk2ms(ulong)
+.br
+.B
+ulong	ms2tk(ulong)
+.br
+.B
 vlong   	fastticks(uvlong *hz)
 .PP
 .EX
@@ -39,6 +50,14 @@
 .B MACHP(0)
 is sometimes used to provide a reference time, since the tick value
 might vary slightly across processors.
+.I Tickscmp
+compares tick values, accounting for wrap around.
+The fuctions
+.I tk2ms
+and
+.I ms2tk
+are specialized versions of the upper case macros below, which
+avoid overflow at the potential cost of speed and precision.
 .PP
 .I Fastticks
 returns the number of ticks since boot as measured by the