X-Authentication-Warning: delorie.com: mail set sender to djgpp-bounces using -f NNTP-Posting-Date: Mon, 04 Aug 2008 23:19:01 -0500 From: "Charles Sandmann" Newsgroups: comp.os.msdos.djgpp References: <89da6560807291624he0cb2d1u696542e552887e8d AT mail DOT gmail DOT com> Subject: Re: djgpp v2 : Control register access segfaults Date: Mon, 4 Aug 2008 23:18:56 -0500 X-Newsreader: Microsoft Outlook Express 6.00.2900.3138 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.3198 X-RFC2646: Format=Flowed; Original Message-ID: Lines: 21 X-Usenet-Provider: http://www.giganews.com NNTP-Posting-Host: 64.91.192.48 X-Trace: sv3-mK8uhJhNnmBJ60aerksHmCbsqw4uSQSTHnRU+FSd55fVjlF16TFsTNygbUt8cGchlRJBkCm1ON03lCV!zNfKBra791tpA6Rwdbsy+UgTk7URWCYFoJI2I9Mz4SGM8Uiffg35sAs+99H19yBfB+1bjcLXIM+P!DlbnGKmGAOOXKgz1vic3WnpxZHrKVmo= X-Abuse-and-DMCA-Info: Please be sure to forward a copy of ALL headers X-Abuse-and-DMCA-Info: Otherwise we will be unable to process your complaint properly X-Postfilter: 1.3.39 X-Original-Bytes: 2114 To: djgpp AT delorie DOT com DJ-Gateway: from newsgroup comp.os.msdos.djgpp Reply-To: djgpp AT delorie DOT com Lael Jones" wrote in message news:89da6560807291624he0cb2d1u696542e552887e8d AT mail DOT gmail DOT com... >I'm upgrading my application from djgpp v1 to djgpp v2 and am seeing a seg >fault in the debug build when the application tries to access (read or > >write) control registers (specifically CR4). The inline assembly I am >using is: > // Enable SSE instructions via OSFXSR (bit 9 of CR4). > The seg fault always occurs on "movl %%cr4, %%eax". > Are there any known issues/changes to djgpp that would cause this? As mentioned elsewhere, djgpp v1's go32 ran at ring 0 in non-dpmi environments. The default cwsdpmi runs at ring 3. cwsdpr0 can run at ring 0 if that's needed, as can pmode and some other dpmi providers. I've also been convinced to update both r5 and r6 of cwsdpmi to automatically set the OSFXSR bit (and update contact info) - if you or anyone else wants to test the updates before release send me an email.