Interrupts and Exceptions,
Continued
Interrupt
Priority Levels
Table 1–3 lists KA49 interrupt conditions, associated priority
levels, and SCB offsets. Note that Table 1–3 is intended as a
quick reference, and may not include all possible causes of the
various interrupts.
Table 1–3 Interrupt Priority Levels
Priority Level
Interrupt Condition
SCB Offset
1F
HALT_H asserted (nonmaskable)
**
1E
Unused
1D
Bcache addressing errors
60
Bcache uncorrectable data ECC errors on
Bcache read for a write that hits valid/owned
60
NVAX read timeout or read data error
on Bread for a write after the requested
quadword has arrived
60
Illegal length write transaction to memory or
I/O
60
Reserved command detected by memory or I/O
during write transaction
60
Pending write times out waiting for disown
write
60
Disown write to unowned memory location
60
Main memory NXM errors on writes
60
NDAL parity errors on writes
60
CP-Bus NXM/TIMEOUT on a write
60
1C
Unused
1B
Performance monitoring interrupt (internally
handled by microcode)
** These conditions generate a hardware halt procedure with a halt code of 2 (external halt).
Continued on next page
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