Date: Sat, 30 Jan 1999 10:57:42 +1030 From: Greg Lehey <grog@lemis.com> To: Garrett Wollman <wollman@khavrinen.lcs.mit.edu> Cc: Brian Feldman <green@unixhelp.org>, chat@FreeBSD.ORG Subject: You are not expected to understand this (was: btokup().. patch to STYLE(9) (fwd)) Message-ID: <19990130105741.X8473@freebie.lemis.com> In-Reply-To: <199901291708.MAA22267@khavrinen.lcs.mit.edu>; from Garrett Wollman on Fri, Jan 29, 1999 at 12:08:02PM -0500 References: <19990129004749.A8899@netmonger.net> <Pine.BSF.4.05.9901291128380.21302-100000@janus.syracuse.net> <199901291708.MAA22267@khavrinen.lcs.mit.edu>
next in thread | previous in thread | raw e-mail | index | archive | help
On Friday, 29 January 1999 at 12:08:02 -0500, Garrett Wollman wrote: > <<On Fri, 29 Jan 1999 11:29:29 -0500 (EST), Brian Feldman <green@unixhelp.org> said: > >> I seem to remember there once was a comment in a well-known body of code, which >> went something like: >> "You are not supposed to understand this." > > The comment was actually ``You are not expected to understand this'', > and it was in v7's swtch(). Almost. From the Sixth Edition, /usr/sys/ken/slp.c, the end of swtch(): rp = p; curpri = n; /* * Switch to stack of the new process and set up * his segmentation registers. */ retu(rp->p_addr); sureg(); /* * If the new process paused because it was * swapped out, set the stack level to the last call * to savu(u_ssav). This means that the return * which is executed immediately after the call to aretu * actually returns from the last routine which did * the savu. * * You are not expected to understand this. */ if(rp->p_flag&SSWAP) { rp->p_flag =& ~SSWAP; aretu(u.u_ssav); } /* * The value returned here has many subtle implications. * See the newproc comments. */ return(1); } This code had changed completely by the Seventh Edition (and the directory name had changed to /usr/sys/sys). Greg -- See complete headers for address, home page and phone numbers finger grog@lemis.com for PGP public key To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-chat" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?19990130105741.X8473>