NetBSD master CVS tree commits

[source%NetBSD.ORG@localhost]

thorpej
Sat Jan 17 16:05:35 PST 1998
Update of /cvsroot/src/sys/arch/alpha/common
In directory netbsd1:/var/slash-tmp/cvs-serv10696

Modified Files:
        sgmap_common.c sgmap_typedep.c sgmapvar.h 
Log Message:
Implement a prefetch spill page for SGMAP DMA.  This works around a slight
annoyance on systems that prefetch the next page during memory -> device
DMA if the DMA comes within a certain distance of the end of the current
page.  This could cause machine checks since the PTE after the last page
would not have the valid bit set.

(I'm not going to complain about this slight kludge too much, since prefetch
makes DMA much faster...)