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| author | adrian <adrian@FreeBSD.org> | 2008-03-18 08:39:11 +0000 |
|---|---|---|
| committer | adrian <adrian@FreeBSD.org> | 2008-03-18 08:39:11 +0000 |
| commit | 63f525812cee08ddad6461a0acdb49f9ea31ef2f (patch) | |
| tree | 622c4f699cb3263ced49fbf0620fb29bdc394a0e /sys/kern/subr_disk.c | |
| parent | 26e3101bd970c1bf9ffd781cd07ea7a57c1c2554 (diff) | |
| download | FreeBSD-src-63f525812cee08ddad6461a0acdb49f9ea31ef2f.zip FreeBSD-src-63f525812cee08ddad6461a0acdb49f9ea31ef2f.tar.gz | |
Sign-extend the 48-bit AMD PMC counter before treating it to a 64-bit
2's compliment.
The 2's compliment transform is done so a "count down" sampling interval
can be converted into a "count up" PMC value. a 2's complimented 'count down'
value is written to the PMC counter; then the read-back counter is reverted
via another 2's compliment.
PR: kern/121660
Reviewed by: jkoshy
Approved by: jkoshy
MFC after: 1 week
Diffstat (limited to 'sys/kern/subr_disk.c')
0 files changed, 0 insertions, 0 deletions
