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Diffstat (limited to 'src/supervisor.adoc')
| -rw-r--r-- | src/supervisor.adoc | 12 |
1 files changed, 8 insertions, 4 deletions
diff --git a/src/supervisor.adoc b/src/supervisor.adoc index 9b92dcb..f79db77 100644 --- a/src/supervisor.adoc +++ b/src/supervisor.adoc @@ -1231,11 +1231,15 @@ indicates the virtual page has been read, written, or fetched from since the last time the A bit was cleared. The D bit indicates the virtual page has been written since the last time the D bit was cleared. -Two schemes to manage the A and D bits are permitted: +Two schemes to manage the A and D bits are defined: -* When a virtual page is accessed and the A bit is clear, or is written -and the D bit is clear, a page-fault exception is raised. -* When a virtual page is accessed and the A bit is clear, the PTE is +* The _Svade_ extension: when a virtual page is accessed and the A bit is + clear, or is written and the D bit is clear, a page-fault exception is + raised. + +* When the Svade extension is not implemented, the following scheme applies. + + + + When a virtual page is accessed and the A bit is clear, the PTE is updated to set the A bit. When the virtual page is written and the D bit is clear, the PTE is updated to set the D bit. When G-stage address translation is in use and is not Bare, the G-stage virtual pages may be |