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| author | Andrew Waterman <andrew@sifive.com> | 2024-01-29 18:25:10 -0800 |
|---|---|---|
| committer | Andrew Waterman <andrew@sifive.com> | 2024-01-30 15:59:02 -0800 |
| commit | 3703643056efecd333a23ca7601e0d57a5395931 (patch) | |
| tree | a1a161896b60790f74088177cca2b1d691c470df /src/supervisor.adoc | |
| parent | e9a2d082c5f1119285bd13147aab347d59b9af4a (diff) | |
| download | riscv-isa-manual-3703643056efecd333a23ca7601e0d57a5395931.zip riscv-isa-manual-3703643056efecd333a23ca7601e0d57a5395931.tar.gz riscv-isa-manual-3703643056efecd333a23ca7601e0d57a5395931.tar.bz2 | |
Implicitly define the Svade extension
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 |