From: jnc@mercury.lcs.mit.edu (Noel Chiappa)
Subject: [TUHS] Early Unix function calls: expensive?
Date: Mon, 4 Jan 2016 07:53:10 -0500 (EST) [thread overview]
Message-ID: <20160104125310.9379718C0A1@mercury.lcs.mit.edu> (raw)
> that's 28+13 = 41 memory cycles.
> ...
> purely in overhead (counting putting the args on the stack as overhead).
Oh, I missed an instruction for de-stacking the arguments, which was typically
something like 'add #N, sp', so another two instruction word fetches, or 43
cycles.
Ironically, if N=4, the compiler used to emit a 'cmp (sp)+, (sp)+', which is
more efficient space-wise (one word instead of two), but less time-wise
(3 cycles instead of 2).
Noel
next reply other threads:[~2016-01-04 12:53 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-04 12:53 Noel Chiappa [this message]
-- strict thread matches above, loose matches on Subject: below --
2016-01-04 2:21 Clem Cole
2016-01-04 1:59 Norman Wilson
2016-01-04 15:09 ` John Cowan
2016-01-04 1:31 Noel Chiappa
2016-01-04 2:24 ` scj
2016-01-04 4:24 ` Larry McVoy
[not found] <mailman.3.1451865187.15972.tuhs@minnie.tuhs.org>
2016-01-04 1:08 ` Johnny Billquist
2016-01-04 1:29 ` Larry McVoy
2016-01-03 23:35 Warren Toomey
2016-01-03 23:53 ` Tim Bradshaw
2016-01-04 0:01 ` John Cowan
2016-01-04 4:40 ` Armando Stettner
2016-01-04 8:52 ` Tim Bradshaw
2016-01-04 17:29 ` Larry McVoy
2016-01-04 13:50 ` Clem Cole
2016-01-05 2:00 ` Ronald Natalie
2016-01-05 15:13 ` Clem Cole
2016-01-05 16:46 ` John Cowan
2016-01-05 17:33 ` Diomidis Spinellis
2016-01-05 17:42 ` Clem Cole
2016-01-05 17:28 ` Ronald Natalie
2016-01-05 17:43 ` Clem Cole
2016-01-05 17:46 ` Ronald Natalie
2016-01-05 18:03 ` Warner Losh
2016-01-05 18:24 ` Ronald Natalie
2016-01-05 20:26 ` scj
2016-01-05 20:49 ` John Cowan
2016-01-05 23:24 ` Dave Horsfall
2016-01-05 23:55 ` Ronald Natalie
2016-01-04 0:00 ` John Cowan
2016-01-04 0:42 ` scj
2016-01-04 11:35 ` Tony Finch
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