Date: Thu, 10 Apr 2003 12:37:16 -0600 From: Warner Losh <imp@harmony.village.org> To: John Baldwin <jhb@FreeBSD.org> Cc: cvs-all@FreeBSD.org Subject: Re: cvs commit: src/sys/dev/pccard pccard.c pccardvar.h Message-ID: <200304101837.h3AIbGA7021295@harmony.village.org> In-Reply-To: Your message of "Thu, 10 Apr 2003 12:42:02 EDT." <XFMail.20030410124202.jhb@FreeBSD.org> References: <XFMail.20030410124202.jhb@FreeBSD.org>
next in thread | previous in thread | raw e-mail | index | archive | help
In message <XFMail.20030410124202.jhb@FreeBSD.org> John Baldwin writes: : At this point it doesn't matter since you only check one field now, but : there was definitely a logic bug in both 1.76 and 1.78. If you want to : terminate a loop when both a and b are zero, you can do either: : : for (...; a != 0 || b != 0; ...) : : or: : : for (...; !(a == 0 && b == 0); ...) : : However, both 1.76 and 1.78 did: : : for (...; a != 0 && b != 0; ...) : : Which will terminate the first time either a or b is zero, not when : both are zero. The fact that my wavelan card didn't probe until : 1.77 should help to prove that. Actually, this is the classic problem of the contrapositive: (!(a == 0 && b == 0))) == (a != 0 || b != 0) So there was a logic bug. Warner
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?200304101837.h3AIbGA7021295>