Parse Trees
A-3
A parse tree represents the way the system "sorts" an error condition. The
four types of error conditions are machine check, hard error (INT60), soft
error (INT54), and IPL 17 errors for the IOP module and the DWLMA
adapter.
In Example A-1, a machine check error occurred. In the error report, the
error was identified as a MCHK_SYNC_ERROR (
1
) with a code number
of 06 (
2
).
There are many conditions that can cause a MCHK_SYNC_ERROR. To
determine what caused the error, follow this branch of the parse tree and
evaluate each condition. The first condition under MCHK_SYNC_ERROR
is ICSR.LOCK (
3
). If the ICSR.LOCK bit was set, you would then
branch off and evaluate each condition under ICSR.LOCK to determine the
type of error. In this case, there are three types of errors: VIC data parity
error, VIC tag parity error, and inconsistent error.
NOTE: Inconsistent errors are usually fatal errors since the machine state
is not understood.
If the ICSR.LOCK bit was not set, you would advance to the next error
condition, not PCSRS.PTE_ER (
4
). If this condition was met, you would
branch off here and evaluate the conditions listed on this branch of the
parse tree.