From mboxrd@z Thu Jan  1 00:00:00 1970
From: jnc@mercury.lcs.mit.edu (Noel Chiappa)
Date: Mon,  4 Jan 2016 07:53:10 -0500 (EST)
Subject: [TUHS] Early Unix function calls: expensive?
Message-ID: <20160104125310.9379718C0A1@mercury.lcs.mit.edu>

    > 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