Date: Sat, 03 Mar 2018 14:02:50 -0700 From: Ian Lepore <ian@freebsd.org> To: Konstantin Belousov <kostikbel@gmail.com> Cc: Hans Petter Selasky <hselasky@FreeBSD.org>, src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: Re: svn commit: r330352 - in head/sys/compat/linuxkpi/common: include/linux src Message-ID: <1520110970.23690.20.camel@freebsd.org> In-Reply-To: <20180303204913.GI3194@kib.kiev.ua> References: <201803031854.w23IsHxm086835@repo.freebsd.org> <1520104482.23690.15.camel@freebsd.org> <20180303204913.GI3194@kib.kiev.ua>
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On Sat, 2018-03-03 at 22:49 +0200, Konstantin Belousov wrote: > On Sat, Mar 03, 2018 at 12:14:42PM -0700, Ian Lepore wrote: > > > > To really avoid roundoff errors, use mstosbt(ms) instead of SBT_1MS*ms. > > > > The rounding errors when multiplying or dividing by SBT_1MS is not > > severe like it is with SBT_1NS, but the inline functions still do the > > arithmetic more correctly to avoid roundoff error. > BTW mstosbt() and other functions have weird bracing in the formula. I > think that the formula as calculated by the C operator precedence is > fine, i.e. multiplication is done before right shift. But the bracing > is redundand then, because the '()' pair next to the return () braces by > inclusion is tautological. > Oh, on looking closer, it's not a paste-o, I just didn't put the closing paren where I had intended to for making it clear the shift happens last. (So almost everyone except me is still going to think a fix has redundant parens.) -- Ian
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