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| author | Andrew Waterman <andrew@sifive.com> | 2017-04-03 21:36:00 -0700 |
|---|---|---|
| committer | Andrew Waterman <aswaterman@gmail.com> | 2017-04-10 21:28:13 -0700 |
| commit | 676bd3db6b6c8e8565ed121229e2c8a7f4d0f20a (patch) | |
| tree | e8d65555bcf78f639f46ce87b5b32481004aa3bc /src | |
| parent | e907eb5f1034045b3be23fa421a36d6df1c638da (diff) | |
| download | riscv-isa-manual-676bd3db6b6c8e8565ed121229e2c8a7f4d0f20a.zip riscv-isa-manual-676bd3db6b6c8e8565ed121229e2c8a7f4d0f20a.tar.gz riscv-isa-manual-676bd3db6b6c8e8565ed121229e2c8a7f4d0f20a.tar.bz2 | |
Clarify WFI w.r.t. interrupt delegation
Diffstat (limited to 'src')
| -rw-r--r-- | src/machine.tex | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/src/machine.tex b/src/machine.tex index 5f03641..b5dc5b1 100644 --- a/src/machine.tex +++ b/src/machine.tex @@ -1909,10 +1909,11 @@ the {\em rs1} and {\em rd} fields, so non-zero values in these fields should now raise illegal instruction exceptions. \end{commentary} -The WFI instruction can also be executed when interrupts are disabled. -The operation of WFI must be unaffected by the global interrupt bits -in {\tt mstatus} (MIE/SIE/UIE) (i.e., the hart must resume if a -locally enabled interrupt becomes pending), but should honor the +The WFI instruction can also be executed when interrupts are disabled. The +operation of WFI must be unaffected by the global interrupt bits in {\tt +mstatus} (MIE/SIE/UIE) and the delegation registers {\tt [m|s|u]ideleg} +(i.e., the hart must resume if a locally enabled interrupt becomes pending, +even if it has been delegated to a less-privileged mode), but should honor the individual interrupt enables (e.g, MTIE) (i.e., implementations should avoid resuming the hart if the interrupt is pending but not individually enabled). WFI is also required to resume execution for |