Date: Fri, 22 Oct 1999 10:35:29 -0400 (EDT) From: Andrew Gallatin <gallatin@cs.duke.edu> To: Terry Lambert <tlambert@primenet.com> Cc: freebsd-alpha@FreeBSD.ORG Subject: Re: ata busmaster i/o port on alpha Message-ID: <14352.29097.552059.840074@grasshopper.cs.duke.edu> In-Reply-To: <199910220140.SAA05716@usr07.primenet.com> References: <14348.40785.536064.278837@grasshopper.cs.duke.edu> <199910220140.SAA05716@usr07.primenet.com>
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Terry Lambert writes: > > > So, my question: Is are you loosing the upper 16 bits for a reason, > > or is it valid to look at the upper 16 bits on all platforms? > > It's truly cool to see that there are people with more Alpha > knowledge than x86 knowledge who are FreeBSD junkies. 8-). Yep. I fully admit that I don't really know how a PC works. I know a hell of a lot more about alphas. > This masking is a bit of historical arcanum dating back to the > IBM PC AT. > > On x86, the I/O address space wraps. Some code depends on this > behaviour. > > This masking should probably be done in a (platform changeable) > macro, in any case. I thought that might be the case, OK, a macro sounds like the right thing to do then. Thanks for the explanation. Cheers, Drew ------------------------------------------------------------------------------ Andrew Gallatin, Sr Systems Programmer http://www.cs.duke.edu/~gallatin Duke University Email: gallatin@cs.duke.edu Department of Computer Science Phone: (919) 660-6590 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-alpha" in the body of the message
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