Interrupts and Exceptions,
Continued
Trap
Exceptions
A trap is an exception that occurs at the end of the instruction
that caused the exception. Therefore, the PC saved on the stack is
the address of the next instruction that would normally have been
executed.
Fault
Exceptions
A fault is an exception that occurs during an instruction and that
leaves the registers and memory in a consistent state such that
elimination of the fault condition and restarting the instruction
will give correct results. After the instruction faults, the PC saved
on the stack points to the instruction that faulted.
Abort
Exceptions
An abort is an exception that occurs during an instruction.
An abort leaves the value of registers and memory
UNPREDICTABLE such that the instruction cannot necessarily
be correctly restarted, completed, simulated, or undone. In most
instances, the NVAX microcode attempts to convert an abort into
a fault by restoring the state that was present at the start of the
instruction that caused the abort.
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