Date: Sun, 18 Mar 2012 00:52:23 +0100 From: Tijl Coosemans <tijl@freebsd.org> To: Bruce Evans <brde@optusnet.com.au> Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org, Julian Elischer <julian@freebsd.org> Subject: Re: svn commit: r233043 - head/sys/i386/include Message-ID: <201203180052.29167.tijl@freebsd.org> In-Reply-To: <20120317223612.D2494@besplex.bde.org> References: <201203161942.q2GJgdPU032060@svn.freebsd.org> <4F642A1A.4070006@freebsd.org> <20120317223612.D2494@besplex.bde.org>
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--nextPart12110572.yYjvuLxiXs Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable On Saturday 17 March 2012 12:48:17 Bruce Evans wrote: > On Fri, 16 Mar 2012, Julian Elischer wrote: >> On 3/16/12 12:42 PM, Tijl Coosemans wrote: >>> int32_t en_sw; /* status word (16bits) */ >> >> what's wrong with this picture? >=20 > Only the excessive indentation in the new version. There's only one tab in the uint16_t fields and style(9) says two tabs for the other fields is ok unless it affects at least 90% of the fields which isn't the case here. > The 16 in the comment is not mismatched with 32 in the code, but is > less needed that before, since it is more obvious that the code uses > 32 and it goes without saying that this would only be used if it is > correct. The comment says that although field has 32 bits in memory, > only 16 bits of it are used in the status word register. For fields > in this struct that use all of the bits in memory, no comment is made > about the number of bits in the register, and vice versa. I forget > if the padding bits in memory are read or written by the hardware. On > write, they might not be touched, or they might be filled with garbage, > or all zeros, or all 1's, or a "reserved" not-quite garbage value. > Probably closest the latter, with the actual bits being all 0 or all > 1. On read, they might be ignored or checked for garbage. I think > they are ignored for this file.d AMD documentation says the upper 16 bits are "reserved,ignored" which means their value is indeterminate, but the cpu doesn't care about them. --nextPart12110572.yYjvuLxiXs Content-Type: application/pgp-signature; name=signature.asc Content-Description: This is a digitally signed message part. -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.18 (FreeBSD) iF4EABEIAAYFAk9lI7wACgkQfoCS2CCgtiuWtwD/dgrxDW/F7ESV3TybI1rpQjc4 RNqV8+0cgOke2BQRxccA/3XUIZHY7AiWTMk3c/lT2QMsj4PgKcdDP31WDNF6g7DZ =sc3k -----END PGP SIGNATURE----- --nextPart12110572.yYjvuLxiXs--
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