In message <c636b079.7d49%james.p....@jpl.nasa.gov>, "Lux, James P" writes:
>An integer divide in software is quite fast
>(unless you're working with something like a Z80).
You only need to divide when you want to change your estimate of the
counters range, for generating timestamps a multiplication will do.
>There's no real advantage in having "hardware" count seconds.. It takes more
>gates to count by arbitrary N than 2^M.
Not only that, it makes the calculation of timeintervals as differences
between two timestamps a royal mess:
#define timersub(tvp, uvp, vvp) \
do { \
(vvp)->tv_sec = (tvp)->tv_sec - (uvp)->tv_sec; \
(vvp)->tv_usec = (tvp)->tv_usec - (uvp)->tv_usec; \
if ((vvp)->tv_usec < 0) { \
(vvp)->tv_sec--; \
(vvp)->tv_usec += 1000000; \
} \
} while (0)
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
p...@freebsd.org | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
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