S390 Interrupts
An exception on the S390 architecture is recognized depending on the context of the instruction.
External Interrupt
An external interrupt is produced when the CPU timer or an external devices triggers said interrupt.
Supervisor Call Interrupt
The supervisor call generates an interrupt which will place the current PSW into the FLCSOPSW (Service Old PSW). Then load the new PSW from FLCSNPSW (Service New PSW). The location of the SVC code is placed at FLCESICODE
Input/Output Interrupt
This interrupt is generally triggered when a device completes execution of a command program.
Program Check Exception
A program exception is recognized when an invalid address is accessed or an invalid instruction is executed.
Specification Exception
Generally produced when the given arguments or registers to an instruction are invalid.
Machine Check Exception
Produced when part of the equipment reports a malfunction. Usually means that said device should be replaced and it's up to the user to do that.