164 Introduction to the New Mainframe: Large-Scale Commercial Computing
Bit 13 indicates that machine check interrupts can occur on this CP. This is
only off when a machine check is being handled.
Bit 14 indicates that there is no more work to run on the CP and it should wait
for an interrupt.
Bit 15 indicates the problem state. When this is off, the CP is running in
supervisor state and restricted instructions are allowed to be executed.
Bits 16 and 17 indicate the translation mode for cross-memory functions.
Bits 18 and 19 are a condition code. They indicate the outcome of an
instruction. For example, if two values are compared, the condition code
indicates high, low, or equal.
Bits 20 to 23, when set off, prevent certain program ...