Date: Wed, 12 Nov 1997 22:01:37 +0000 (GMT) From: Terry Lambert <tlambert@primenet.com> To: tlambert@primenet.com (Terry Lambert) Cc: handy@sag.space.lockheed.com, roberto@keltia.freenix.fr, current@FreeBSD.ORG Subject: Re: make world time???/ Message-ID: <199711122201.PAA20601@usr05.primenet.com> In-Reply-To: <199711122019.NAA07092@usr09.primenet.com> from "Terry Lambert" at Nov 12, 97 08:19:03 pm
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> 1) Allocate a buffer in low memory at some offset "x".
> 2) Allocate a buffer in high memory at 16M + x
> 3) Allocate a compare buffer somewhere.
> 4) Schedule a bus mastering DMA read into the low memory
> buffer; wait for it to complete
> 5) Copy the low memory buffer contents to the compare buffer
> 6) XOR some non-zero pattern into the low memory buffer
> 7) Copy the low memory buffer contents to the high memory buffer
> 8) Schedule a bus mastering DMA read into the low memory
^^^^ - UGH!
I meant to say "high" here...
> buffer; wait for it to complete
> 9) Compare the compare buffer contents against the low memory
> and high memory buffer contents.
> 10) If the compare buffer contents matches the low memory buffer
> contents, set the "USEBOUNCEBUFFERS" flag on the controller.
Terry Lambert
terry@lambert.org
---
Any opinions in this posting are my own and not those of my present
or previous employers.
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