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P4080 illegal op-code exception

Question asked by Bob Perry on Feb 29, 2016
Latest reply on Mar 8, 2016 by Scott Wood

I have a P4080 system which is generating random exceptions.  The exception is a program fault and the ESR indicates an illegal op-code.  I did find that the instruction cache entry for this address was NULL.  Infact, the entire way was all NULL although looking at that memory address should valid instructions.  i have now disabled the instruction cache and also the data cache and i am still seeing the same fault.  The fault occurs in random places and also at random times.  I can execute the same code 100 times without fault and then get a series of faults all in different memory locations.  However, the dumping memory at the location of SRR0 shows valid op-codes.  Can anyone throw any light on what the problem maybe.